Introduction
The duration of pregnancy has been traditionally considered to be 10 lunar months or 40 weeks or 280 days. It is customary to divide the entire period of gestation into three trimesters: first trimester (until 14 weeks); second trimester (15–28 weeks); third trimester (29–42 weeks). The gestational age is usually calculated from the first day of LMP. During the antenatal period, planned antenatal care is given to a pregnant woman in order to ensure good maternal and neonatal outcome.
History
History at the Time of First Antenatal Visit
The aim of history taking is to determine the period of gestation and thereby EDD. History taking also helps in determining if the pregnancy is associated with any high risk factors. Taking appropriate history helps the clinician to determine the further management and mode of delivery. Components of complete history elicitation and physical examination are tabulated in Table 1.1.
History of Presenting Complaints
The various complaints with which the woman presents are listed in a chronological order from the time of their onset. These complaints need to be described detailing their mode of onset, severity, aggravating or relieving factors. Regarding the present pregnancy, the following points need to be considered:
- The first day of the LMP must be determined as accurately as possible. The clinician must ask the patient how long she had been married or has been in relationship with the present partner. The clinician must also ask the woman if she had previously received any treatment for infertility. The patient must be asked if the present pregnancy is a planned one and since how long she had been planning this pregnancy. The patient must be enquired if she ever used any contraceptive agents in the past.4
- The clinician needs to take the history of any medical or obstetric problems, which the patient has had since the start of this pregnancy, for example, pyrexial illnesses (such as influenza) with or without skin rashes; symptoms suggestive of a urinary tract infection and history of any vaginal bleeding.
Enquiry must be also made regarding normal symptoms related to pregnancy, which the patient may be experiencing, e.g. nausea and vomiting, heartburn, constipation, etc. Some symptoms, which may be both due to physiological or pathological changes in pregnancy, include abdominal pain (Table 1.2), shortness of breath (Table 1.3), back pain (Table 1.4), etc.
Menstrual History
It is important to elicit the proper history regarding the last (normal) menstrual period. It is also important for the clinician to find out if the previous cycles were normal and regular or not. In absence of regular, predictable, cyclic, spontaneous menstrual cycles, accurate dating of pregnancy based solely on history and clinical examination is impossible. The clinician must also enquire about the length of periods and amount of bleeding. Excessive amount of menstrual blood loss in previous cycles may be associated with anemia.
Last menstrual period can be used for calculating the EDD. To calculate the EDD, 7 days are added to the first day of LMP and then 9 months are added to this date. For example, if the LMP was on February 2, 2014, the EDD will be on November 9, 2014. If the LMP was on October 27, 2013, the EDD will be on August 3, 2014. This method of estimating EDD is known as the Naegele's rule. This rule can also be applied by adding 7 days to the first day of LMP, subtracting 3 months and then adding 1 year to this. The rule should be used to measure the duration of pregnancy, only if the patient had been having regular menstrual cycles previously. Naegele's rule is based on the assumption that pregnancy had begun approximately 2 weeks before ovulation. In clinical practice, this gestational age is used for marking the temporal events occurring during pregnancy. In contrast, ovulatory or fertilization age which is typically 2 weeks lesser is utilized by the embryologists and other reproductive biologists.
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The history of using steroidal contraception prior to conception is important as in this case EDD may not be accurately determined with help of Naegele's rule. This is so as ovulation may not immediately resume following withdrawal bleeding; there may be a delay of 2–3 weeks.
Previous Obstetric History
Details regarding the past obstetric history are important because many complications, which had occurred in the previous pregnancy, are likely to recur again. Each previous pregnancy must be described in a chronological manner with details such as place of delivery, mode of delivery, type of labor, use of any anesthesia or interventions during the labor, presence of any complications at the time of labor or delivery. Details of each delivered baby such as birthweight, APGAR score at birth, sex, time of birth, any complications, immunizations, history of breastfeeding, etc. must be recorded.
Site: Substernal region, anterior mid-thorax.
The woman's past obstetric history must be denoted by the acronym GPAL, where G stands for gravida, P for parity, A for number of abortions and L for number of live births. It is also important to ask the woman, how long she has been married.
Gravida: This refers to the number of pregnancies, including the present pregnancy, the woman has ever had. This is irrespective of the fact whether the pregnancies were viable at the time of birth or not.
Nulligravida: This implies a woman who has never been pregnant.
Primigravida: This stands for a woman who is pregnant for the first time (Gravida 1).
Multigravida: This stands for a woman who has had at least one previous pregnancy, irrespective of whether it was viable or not (depending on the number of previous pregnancies, she could be gravida 2, 3, or more). For example, a woman who has had three previous pregnancies and is now pregnant for the fourth time will be gravida 4.
Abortions: Number of the pregnancies, which have terminated before reaching the point of viability (20 weeks). The clinician must note their exact gestational period and also mention whether they were spontaneous or induced5 abortions; the reason for the induced abortion also needs to be asked.
Viability: This refers to the ability of the fetus to live outside the uterus after birth.
Parity: This refers to the number of previous viable pregnancies (including infants who were either stillborn or born alive). Parity is determined by the number of viable pregnancies and not by the number of fetuses delivered. Thus, parity does not change even if twins or triplets are born instead of a singleton fetus or if woman gives birth to a live or stillborn infant.
Nullipara: A woman who has never carried a previous pregnancy to a point of viability (para 0).
Primipara: Woman who has had one previous viable pregnancy (para 1). For example, if the woman is gravida 4 and only two of the previous pregnancies of this woman were viable, she would be gravida 4, para 2.
Multipara: Woman who has had two or more previous viable pregnancies (para 2, 3, or more).
Grand multipara: Woman who has had five or more previous viable pregnancies (para 5, 6 or more).
Elderly primigravida: Woman having her first pregnancy at the age of 30 years or above.
A woman is considered as a high-risk mother, if she is either a primigravida or nullipara over the age of 30 or if she is a young teenaged primigravida or if she is a grand multipara.
It is important to take the history of previous pregnancies including history of previous abortions (period of gestation < 20 weeks), precipitate labor, preterm pregnancies (period of gestation < 37 completed weeks), abnormal presentations, preeclampsia or eclampsia, cesarean section, retained placenta, postpartum hemorrhage, stillbirths, history of episiotomies, perineal tears, and history of receiving epidural anesthesia during the previous pregnancies. History about any episodes of hospitalization during previous pregnancies can be helpful. History of complications during previous pregnancy, such as preeclampsia, placenta previa, abruptio placentae, IUGR, polyhydramnios or oligohydramnios is important because many complications in previous pregnancies tend to recur in subsequent pregnancies (e.g. patients with a previous history of perinatal death or spontaneous preterm labor or preeclampsia or multifetal gestation are likely to experience the recurrence of these complications in their subsequent pregnancies). It is also important to take the history of previous pregnancy losses. A history of three or more successive first trimester miscarriages suggests a possible genetic abnormality in the father or mother. Previous midtrimester miscarriages could be associated with cervical incompetence. Patient may often forget to give the history about previous miscarriages and ectopic pregnancies. Therefore, the clinician needs to ask specifically about the history of previous miscarriages and ectopic pregnancies. Approximate birthweight of previous children and the approximate period of gestation, especially if the infant was low birthweight or preterm, are useful. Low birthweight at the time of birth is indicative of either IUGR or preterm delivery.
It is important to know if the woman has experienced a prolonged labor during her previous pregnancy, as this may indicate cephalopelvic disproportion. History of previous birth in form of assisted delivery, including forceps delivery, vacuum application and cesarean section, suggest that there may have been cephalopelvic disproportion. In case of previous cesarean delivery, a detailed history of the previous surgery needs to be taken See Chapter 5). The patient should always be asked if she knows the reason for having had a cesarean delivery. She should be asked to show the hospital notes related to the surgery, if available. This may help to provide some information regarding the type of incision made in the uterus, any complications encountered during the surgery, etc. Detailed history of the previous live births as well as of previous perinatal deaths is important. The following points need to be elicited:
Birthweight of each infant born previously: This is important as previous low birthweight infants or spontaneous preterm labors tend to recur during future pregnancies. Also, history of delivering a large-sized baby in the past is suggestive of maternal diabetes mellitus or gestational diabetes, which may recur during subsequent pregnancies.
Method of delivery of each previous infant: The type of previous delivery is also important because a forceps delivery or vacuum extraction may suggest that some degree of cephalopelvic disproportion may have been present. If the patient had a previous cesarean section, the indication for that cesarean section must be determined.
History of previous perinatal deaths: Previous history of having one or more perinatal deaths in the past places the patient at high risk of further perinatal deaths. Therefore, every effort must be made to find out the cause of any previous deaths. If no cause can be found, then the risk of a recurrence of perinatal death is even higher.
Medical History
Patients must be specifically asked about the previous medical history of diabetes, epilepsy, hypertension, renal disease, rheumatic disease, heart valve disease, epilepsy, asthma, tuberculosis, psychiatric illness or any other significant illness that she may have had in the past.
History regarding any previous hospital admission, surgery, blood transfusion, etc. also needs to be taken. It is important to elicit the patient's medical history as some medical conditions may become worse during pregnancy, e.g. a patient with heart valve disease may go into cardiac failure, while a hypertensive patient is at a high risk of developing preeclampsia.6
Treatment History
The woman must be asked if she has previous history of allergy to any drugs (specifically allergy to penicillin), history of receiving immunization against tetanus or administration of Rhesus (Rh) immunoglobulins during her previous pregnancies. The patient must be asked if she had received any treatment in the past (e.g. hypoglycemic drugs, antihypertensive drugs, etc.). Certain drugs may be teratogenic to the fetus during the first trimester of pregnancy, e.g. retinoids, which are used for acne and anticoagulant drugs like warfarin. Also certain drugs, which the women may be regularly taking prior to pregnancy, are relatively contraindicated during pregnancy, e.g. antihypertensive drugs like ACE inhibitors, β-blockers, etc.
Surgical History
The woman must be enquired if she ever underwent any surgery in the past such as cardiac surgery, e.g. heart valve replacement; operations on the urogenital tract, e.g. cesarean section, myomectomy, cone biopsy of the cervix, operations for stress incontinence and vesicovaginal fistula repair, etc.
Family History
Family history of medical conditions, such as diabetes, multiple pregnancy, bleeding tendencies or mental retardation, etc. increases the risk for development of these conditions in the patient and her unborn infant. Since some birth defects are inherited, it is important to take the history of any genetic disorder, which may be prevalent in the family.
Social History
It is important to elicit information regarding the patient's social circumstances. The mother should be asked if she has social or family support to help her bring up the baby, for example, a working mother may require assistance to help her plan the care of her infant. Social problems, like unemployment, poor housing and overcrowding increase the risk of mother developing medical complications like tuberculosis, malnutrition and IUGR. Patients living in poor social conditions need special support and help. Sometimes it may become difficult to ask the patient directly regarding her socioeconomic status. In these cases, taking the history regarding the occupation of the husband or partner is likely to give clues regarding the patient's socioeconomic history. Classification of the women based on their socioeconomic status is usually done using the Kuppuswamy Prasad's classification system* (revised for 2013), which is based on the per capita monthly income (Table 1.5).
Personal History
History of behavioral factors (smoking or tobacco usage, alcohol usage, utilization of prenatal care services, etc.) needs to be taken. The patient should be specifically asked if she has been smoking or consuming alcohol. Smoking and alcohol both may cause IUGR. Additionally, alcohol may also cause congenital malformations.
Family Planning/Contraceptive History
The patient's family planning needs and wishes should be discussed at the time of her first antenatal visit. If she is a multipara having at least two live babies, she should be counseled and encouraged for postpartum sterilization. In case the woman is not willing to undergo permanent sterilization procedure, the patient's wishes should be respected; she can be offered temporary methods of contraception like oral contraceptive pills, Cu-T, etc.
Previous history of use of various contraception methods with details such as type of contraceptive devices used, duration of their use, patient satisfaction, associated problems and complications, etc. also need to be mentioned.
Nutritional History
A record of patient's daily food intake is documented to calculate the daily calorie intake. Caloric values of some commonly used food stuffs have been described in Appendix 1. Dietary history may be particularly important in some pregnancy-related complications where dietary modifications are suggested, e.g. diabetic diet in case of gestational diabetes, iron and protein-rich diet in case of anemia in pregnancy, etc.
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Gynecological History
The clinician must record the history of previous gynecological problems, such as recurrent vaginal discharge, pelvic pain, fibroids, ovarian cysts, previous infertility, etc. The clinician also needs to enquire if some treatment (both medical and surgical) was instituted for any of these problems.
Summary of History
Once the history is complete, a summary is made along with the possible diagnosis or differential diagnosis. This should include the woman's name, age, time since marriage, gravida, parity, any previous miscarriages, number of live children, weeks of gestation and any associated medical or surgical disease along with any other possible complications. This allows differentiation between normal pregnancy and a high-risk pregnancy.
Clinical Presentation
Clinical presentation during various trimesters of pregnancy is as follows:
First Trimester of Pregnancy
- Cessation of menstruation: Cessation of menstrual cycles in a woman belonging to the reproductive age group, who had previously experienced spontaneous, cyclical, predictable periods, is the first most frequent symptom of pregnancy. Since there may be considerable variation in the length of ovarian and thus menstrual cycle amongst women, amenorrhea is not a reliable indicator of pregnancy.
- Nausea and vomiting: Also known as morning sickness, these symptoms appear 1 or 2 weeks after the period is missed and last until 10–12th week. Its severity may vary from mild nausea to persistent vomiting, e.g. hyperemesis gravidarum.
- Urinary symptoms: Increased frequency of urination during the early months of pregnancy is due to relaxant effect of progesterone on the bladder, in combination with the pressure exerted by the gradually enlarged uterus on the bladder.
- Mastodynia: Mastodynia or breast discomfort may be present in early pregnancy and ranges in severity from a tingling sensation to frank pain in the breasts.
- Cervical mucus: High levels of progesterone during pregnancy helps in lowering the concentration of NaCl in cervical mucus, which prevents the formation of ferning pattern; instead the cervical mucus shows an ellipsoid pattern.
Second Trimester of Pregnancy
There is disappearance of subjective symptoms of pregnancy such as nausea, vomiting and frequency of micturition. Other symptoms, which may appear include the following:
- Abdominal enlargement: Progressive enlargement of the lower abdomen occurs due to the growing uterus.
- Fetal movements: Fetal movements generally occur after 18–20th week of gestation.
- Quickening: Fetal movements (quickening) can usually be seen or felt between 16 to 18 weeks of gestation in a multigravida. A primigravida, on the other hand, is capable of appreciating fetal movements after approximately 2 weeks (i.e. 18–20 weeks).
- Fetal heart sounds: This is the most definitive clinical sign of pregnancy and can be detected between 18 to 20 weeks of gestation. The rate usually varies from 120 beats/minute to 160 beats/minute.
- Palpation of fetal body parts: The fetal body can usually be palpated by the 18–20 weeks of gestation unless the patient is obese; there is abdominal tenderness or there is an excessive amount of amniotic fluid.
- External ballottement: This can be elicited as early as 20th week of gestation because the size of fetus is relatively smaller in comparison to the amniotic fluid. In this method, repercussion is felt by the examiner's hand placed on the woman's abdomen when the fetus is given a push externally.
- Internal ballottement: This can be elicited between 16 to 28 weeks of gestation. This is an obsolete method for diagnosing pregnancy. Tip of forefinger of the right hand is placed in the anterior fornix and a sharp tap is made against the lower segment of uterus where the fetus, if present, gets tossed upwards. It is felt by the examiner's finger to strike against the uterine wall as it falls back.
- Skin changes: There is appearance of pigmentation over the forehead and cheeks by 24th week of gestation. There is appearance of linea nigra and stria gravidarum over the abdomen.
Changes in the Third Trimester
- Abdominal enlargement: There occurs progressive enlargement of the abdomen, which can result in development of symptoms of mechanical discomfort such as palpitations and dyspnea. Lightening is another phenomenon, which occurs at approximately 38 weeks of gestation especially in the primigravida. This results in a slight reduction in fundal height, which provides relief against pressure symptoms.8
- Frequency of micturition: There is an increased frequency of micturition, which had previously disappeared in the second trimester.
- Fetal movements become more pronounced: The fetal movements become more pronounced and palpation of fetal parts becomes easier.
- Braxton Hicks contractions become more evident.
- Fetal lie, presentation and period of gestation can be determined.
Changes in Genital Organs
The changes in genital organs occurring at the time of pregnancy are described as follows:
Vagina
- Chadwick's or Jacquemier's sign: The vaginal walls show a bluish discoloration as the pelvic blood vessels become congested. This sign can be observed by 8–10 weeks of gestation.
- Osiander's sign: There is increased pulsation in the vagina felt through the lateral fornix at 8 weeks of gestation.
Uterus
- Enlargement of the uterus occurs due to hypertrophy and hyperplasia of the individual muscle fibers under the influence of hormones such as estrogen and progestogens.
- For the first few weeks of pregnancy, the uterus maintains its original pear shape, but becomes almost spherical by 12 weeks of gestation. Thereafter, it increases more rapidly in length, than in width becoming ovoid in shape. Until 12 weeks, the uterus remains a pelvic organ after which it can be palpated per abdominally.
- The uterus increases in weight from pre-pregnant 70 g to approximately 1,100 g at term.
- Due to uterine enlargement, the normal anteverted position gets exaggerated up to 8 weeks. Since the enlarged uterus lies on the bladder making it incapable of filling, the frequency of micturition increases. However, after 8 weeks the uterus more or less conforms to the axis of the inlet.
- Hegar's sign: At 6–8 weeks of gestation, the cervix is firm in contrast to the soft isthmus. Due to the marked softness of uterine isthmus, cervix and body of uterus may appear as separate organs. As a result, the isthmus of the uterus can be compressed between the fingers palpating vagina and abdomen, which is known as Hegar's sign (Fig. 1.1).
- Palmer's sign: Regular rhythmic uterine contractions, which can be elicited during the bimanual examination can be felt as early as 4–8 weeks of gestation.
- Braxton Hicks contractions: In the early months of pregnancy, uterus undergoes contractions known as Braxton Hicks contractions, which may be irregular, infrequent and painless without any effect on the cervical dilatation and effacement. Towards the last weeks of pregnancy, these contractions increase in intensity, resulting in pain and discomfort for the patient and may occur after every 10–20 minutes, thereby assuming some form of rhythmicity. Eventually, these contractions merge with the contractions of labor.
- There is hypertrophy of the uterine isthmus to about three times its original size during the first trimester of pregnancy.
- Formation of lower uterine segment: After 12 weeks of pregnancy, the uterine isthmus unfolds from above downwards to get incorporated into the uterine cavity and also takes part in the formation of lower uterine segment.
- There is an increase in the uteroplacental blood flow ranging between 450 mL/minute to 650 mL/minute near term. This increase is principally due to vasodilatation.
- Uterine soufflé: This is a soft blowing sound synchronous with the maternal pulse. It is caused by rush of blood through the dilated uterine arteries. On the other hand, fetal soufflé is a sharp whistling sound synchronous with the fetal pulse. It is caused by the rush of blood through the fetal umbilical arteries.
Cervix
- There occurs hypertrophy and hyperplasia of the elastic and connective tissue fibers and increase in vascularity within the cervical stroma. This is likely to result in cervical softening (known as Goodell's sign), which becomes evident by 6 weeks of pregnancy. Increased vascularity is likely to result in bluish discoloration beneath the squamous epithelium of portio vaginalis resulting in a positive Chadwick's sign.9
- With the advancement of pregnancy, there is marked proliferation of endocervical mucosa with downward extension of the squamocolumnar junction. There is copious production of cervical secretions resulting in the formation of a thick mucus plug, which seals the cervical canal.
- When the cervical mucus (secreted during pregnancy) is spread over the glass slide and dried, it shows a characteristic crystallization or beading pattern due to presence of progesterone.
If the history and examination suggest that the patient is pregnant, the diagnosis is usually confirmed by urine pregnancy test or a urine hCG assay. The test becomes positive by the time the first menstrual period is missed. A transvaginal or abdominal scan helps in providing 100% confirmation of pregnancy.
Clinical Examination
GENERAL PHYSICAL EXAMINATION
The general appearance of the patient is of great importance as it can indicate whether or not she is in good health. A woman's height and weight may reflect her past and present nutritional status.
The signs which must be carefully looked for in a pregnant woman include the following:
- Pallor (lower palpebral conjunctiva, palms of the hand, nail beds, tongue, lips).
- Edema [foot (Table 1.6), face, vulva, sacral region]. Simple strategies, which can be used for the alleviation of physiological pedal edema in pregnancy, are reduction of salt and carbohydrate intake in the diet; foot elevation; and use of elastic stockings.
- Jaundice (sclera, nail beds).
- Enlarged lymph nodes (neck, axillae and inguinal areas).
- Thyroid gland: The clinician must look for an obviously enlarged thyroid gland (goiter). In case, there is obvious enlargement of the thyroid gland or it feels nodular, the patient must be referred for further investigations.
- Skin changes: There may be increased skin pigmentation due to increased production of melanotropin. This may manifest as the following:
- Face: Melasma, a frequently encountered skin change during pregnancy
- Breasts: Darkening of areolas
- Abdomen: Linea nigra.
- Signs of past pregnancy such as breast pigmentation, striae gravidarum, abdominal laxity, perineal or vulval damage, perineal repair, any stress incontinence, etc. may be present.
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Examination of the Breasts
There is pronounced pigmentation of the areola and nipples during pregnancy. There is also appearance of secondary areola, Montgomery's tubercles and presence of increased vascularity. Routine breast examination during antenatal examination is not recommended for the promotion of postnatal breastfeeding. The breasts should be examined with the patient both sitting and lying on her back, with her hands above her head. Changes in the breasts are best evident in the primigravida in comparison to multigravida. Presence of secretions from the breasts of a primigravida who has never lactated is an important sign of pregnancy.
SPECIFIC SYSTEMIC EXAMINATION
During pregnancy a detailed abdominal and vaginal examination may be required. Besides this, the other body systems like the respiratory system and the cardiovascular system must also be briefly examined. In case any pathological sign is observed, a detailed examination of the respective body system must be carried out.
ABDOMINAL EXAMINATION
Even in the present time of technological advancements, the clinicians must not underestimate the importance of clinical abdominal examination. The abdominal examination in the antenatal period usually comprises of the following:
- Inspection
- Estimation of height of uterine fundus
- Obstetric grips (Leopold's maneuvers)
- Evaluation of uterine contractions
- Estimation of fetal descent
- Auscultation of fetal heart.
Each of these is described next in detail.
Preparation of the Patient for Examination
- Before starting the abdominal examination, the clinician should ensure that the patient's bladder is empty; she should be asked to empty her bladder in case it is not empty.
- The patient must lie comfortably on her back with a pillow under her head and her abdomen must be fully exposed. She should not lie in a left lateral position.
Inspection of the Abdomen
The following should be specifically looked for at the time of abdominal inspection:
Shape and size of the distended abdomen
- In case of a singleton pregnancy and a longitudinal lie, the shape of the uterus is usually oval.
- The shape of the uterus may be round with a multiple pregnancy or polyhydramnios.
- The flattening of the lower part of the abdomen suggests a vertex presentation with an occipitoposterior position (ROP or LOP).
- A suprapubic bulge may be suggestive of a full bladder.
Presence or absence of scars: In case scar marks as a result of previous surgery are visible, a detailed history must be taken. This should include the reasons of having the surgery and the type of surgery performed [myomectomy or previous lower segment cesarean section (LSCS)]. In case the scar is related to previous LSCS, detailed history as described in Chapter 5 needs to be taken.
Presence of stria gravidarum and linea nigra: In many pregnant women, a black-brownish colored line may sometimes develop in the midline of the abdomen. This is known as linea nigra (Fig. 1.2). In many women, in later months of pregnancy, stretch marks called stria gravidarum (Fig. 1.2) may develop over the skin of abdomen, breast or thighs.
Abdominal Palpation
Besides the fetal and uterine palpation, other abdominal organs like the liver, spleen and kidneys must also be specifically palpated. Presence of any other abdominal mass should also be noted.
The presence of an enlarged organ, or a mass, should be appropriately followed up.
Examination of the Uterus and the Fetus
- The clinician must firstly check whether the uterus is lying in the midline of the abdomen or it is dextroratotated either to the right or the left. In case the uterus is dextrorotated, it needs to be centralized.
- The wall of the uterus must be palpated for the presence of any irregularities. An irregular uterine wall may be suggestive of either the presence of myomas or a congenital abnormality such as a bicornuate uterus. Uterine myomas may enlarge during pregnancy and become painful.
Determining the Fundal Height
In the first few weeks of pregnancy, there is primarily an increase in the anterior posterior diameter of the uterus. By 12 weeks, the uterus becomes globular and attains a size of approximately 8 cm. On the bimanual examination, the uterus appears soft, doughy and elastic. In the initial stages of pregnancy the cervix may appear firm. However with increasing period of gestation, the cervix becomes increasingly softer in consistency. From the second trimester onwards, the uterine height starts corresponding to the period of gestation. The rough estimation of fundal height with increasing period of gestation is shown in Figure 1.3.
Determining size of the uterus through estimation of fundal height: After centralizing the dextrorotated uterus with right hand, the upper border of the uterus is estimated with the ulnar border of the left hand.
Anatomical landmarks used for determining the size of uterus through estimation of fundal height mainly include the symphysis pubis and the umbilicus:
- If the fundus is palpable just above the symphysis pubis, the gestational age is probably 12 weeks.
- If the fundus reaches half way between the symphysis and the umbilicus, the gestational age is probably 16 weeks.
- If the fundus is at the same height as the umbilicus, the gestational age is probably 22 weeks (one finger under the umbilicus = 20 weeks and one finger above the umbilicus = 24 weeks).
- The distance between the xiphisternum and umbilicus is divided into three equal parts. Upper one-third corresponds to 28 weeks; upper two-thirds corresponds to 32 weeks whereas the tip of xiphisternum corresponds to 36 weeks. At 40 weeks, due to the engagement of fetal head, the height of the uterus reduces slightly and corresponds to the level of 32 weeks. As a result even though the fundal height is same at 32 weeks and 40 weeks of gestation, at 32 weeks the fetal head is free floating, while it is engaged at 40 weeks of gestation.
- At every antenatal visit from 28 weeks of gestation onwards, the wellbeing of the fetus must be assessed. Having determined the height of the fundus, the clinician needs to assess whether the height of the fundus corresponds to the patient's dates and to the size of the fetus.
Measurement of symphysisfundus (S-F) height: Method of measuring the S-F height is shown in Figure 1.4. After centralizing the dextrorotated uterus, the upper border of the fundus is located by the ulnar border of left hand and this point is marked by placing one finger there. The distance between the upper border of the symphysis and the marked point is measured in centimeter with help of a measuring tape. After 24 weeks, the S-F height, measured in centimeters corresponds to the period of gestation up to 36 weeks. Though a variation of 2 cm (more or less) is regarded as normal, there are numerous conditions where the height of uterus may not correspond to the period of gestation (Table 1.7). If the fundus is palpable just above the symphysis pubis, the gestational age is probably 12 weeks.
Palpation of the Fetus
The lie and presenting part of the fetus only becomes important when the gestational age reaches 34 weeks. The following must be determined:
Fetal Lie
Fetal lie refers to the relationship of cephalocaudal axis or long axis (spinal column) of fetus to the long axis of the centralized uterus or maternal spine. The lie may be longitudinal, transverse or oblique (Figs 1.5A to D).
- Longitudinal lie: The fetal lie can be described as longitudinal when the maternal and fetal long axes are parallel to each other.
- Transverse lie: The fetal lie can be described as transverse when the maternal and fetal long axes are perpendicular to each other.
- Oblique lie: The fetal lie can be described as oblique when the maternal and fetal long axes cross each other obliquely or at an angle of 45°. The oblique lie is usually unstable and becomes longitudinal or transverse during the course of labor.
Fetal Presentation
Fetal presentation can be described as the fetal body part, which occupies the lower pole of the uterus and thereby first enters the pelvic passage. Fetal presentation is determined by fetal lie and may be of three types: cephalic (head), podalic (breech), or shoulder (Figs 1.6A to E).
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Figs 1.5A to D: Fetal lie. (A) Longitudinal lie (vertex presentation); (B) Longitudinal lie (breech presentation); (C) Transverse lie (shoulder presentation); (D) Oblique lie
Figs 1.6A to E: Type of fetal presentation. (A) Vertex presentation; (B) Breech presentation; (C) Shoulder presentation; (D) Brow presentation; (E) Face presentation
Cephalic or the head presentation is the most common and occurs in about 97% of fetuses. Breech and shoulder presentations are less common and may pose difficulty for normal vaginal delivery. Thus, these two presentations are also known as malpresentations. As described previously, in cephalic presentation, the fetal head presents first. Depending on the part of fetal head presenting first, cephalic presentation can be divided as follows:
Vertex or occiput presentation: When the head is completely flexed onto chest, the smallest diameter of the fetal head (suboccipitobregmatic diameter) presents. In these cases, the occiput is the presenting part. Usually the occiput presents anteriorly. In some cases, occiput may be present posteriorly (Figs 1.7A and B). This type of presentation is known as occipitoposterior position. Though most of the cases with occipitoposterior position undergo normal vaginal delivery, labor is usually prolonged in these cases. In some cases with occipitoposterior presentation, cesarean delivery may be required13.
Face presentation: When the fetal head is sharply extended, occiput and the back are in contact with one another. In these cases, face is the foremost part of fetal head inside the birth canal and it presents first.
Brow presentation: When the fetal head is only partially extended, fetal brows are the foremost part of fetal head inside the birth canal and they present first. Brow presentation is usually transient because with the progress of labor, as further extension of neck takes place, brow presentation almost invariably gets converted into face presentation. If the brow presentation remains persistent, the labor gets arrested and a cesarean section is almost always required.
Sinciput presentation: When the fetal head is only partially flexed, the anterior fontanel or bregma is the foremost inside the birth canal and it presents. With progress of labor, as the flexion of neck takes place, sinciput presentation invariably gets converted into vertex presentation.
Compound presentation: Compound presentation is a term used when more than one part of the fetus presents (Fig. 1.8). For example, presence of fetal limbs alongside the head in case of a cephalic presentation or one or both arms in case of breech presentation. This can commonly occur in case of preterm infants.
Since fetal presentation can undergo a change in the early weeks of gestation, fetal presentation should be reassessed by abdominal palpation at 36 weeks or later, when fetal presentation is unlikely to change by itself and it is likely to influence the plans for the birth. In case of suspected fetal malpresentation, an ultrasound examination must be performed to confirm the presentation.
Presenting Part
This can be defined as the part of fetal presentation which is foremost within the birth canal and is therefore first felt by the clinician's examining fingers:
- Cephalic: In case of cephalic presentation, the fetal presenting parts are as follows:
- Completely flexed fetal head: Vertex
- Deflexed fetal head: Sinciput
- Partially extended fetal head: Brow
- Completely extended fetal head: Face
- Breech presentation: In case of breech presentation, the fetal presenting part is the sacrum.
- Shoulder presentation: In case of shoulder presentation, fetal presenting part is the back.
Fetal Attitude
Fetal attitude refers to the relationship of fetal parts to each other (Figs 1.9A to D). The most common fetal attitude is that of flexion in which the fetal head is flexed over the fetal neck; fetal arms are flexed unto chest and the fetal legs are flexed over the abdomen.
Denominator
Denominator can be described as an arbitrary fixed bony point on the fetal presenting part (Table 1.8).
Fetal Position
Fetal position can be defined as the relationship of the denominator to the different quadrants of maternal pelvis (anterior, transverse and posterior).14
Figs 1.9A to D: Different types of fetal attitudes. (A) Complete flexion; (B) Marked deflexion; (C) Partial extension; (D) Complete extension
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Since the presenting part would be either directed to the left or right side of maternal pelvis, six positions would be possible for each of the fetal presentation. For example, with vertex presentation, the six positions that would be possible are LOA, ROA, LOT, ROT, LOP and ROP (Figs 1.10A and B). The fetal position gives an idea regarding whether the presenting part is directed towards the front, back, left or right of the birth passage.
Diagnosis of Fetal Presentation and Position
It is most important for the clinician to correctly identify the fetal presentation and position. This is usually done by performing Leopold's maneuvers on abdominal examination or via vaginal examination.
Obstetric Grips or Leopold's Maneuvers of Abdominal Palpation
Obstetric grips which help in determining fetal lie and presentation are also known as Leopold's maneuvers. Leopold's maneuvers basically include four steps and must be performed while the woman is lying comfortably on her back. The examiner faces the patient for the first three maneuvers and faces towards her feet for the fourth. Obstetric grips must be conducted when the uterus is relaxed and not when the woman is experiencing contractions (Figs 1.11A to D).
Maternal Position
The mother should be comfortable lying in supine position and her abdomen is to be bared. She should be asked to semiflex her thighs in order to relax the abdominal muscles.
These maneuvers can be performed throughout the third trimester and between the contractions, when the patient is in labor. These grips help in determining fetal lie and presentation. The fetal head feels hard and round, and is easily movable and ballotable. The breech feels soft, broad and irregular and is continuous with the body. Besides estimating the fetal lie and presentation, many experienced clinicians are also able to estimate fetal size and weight through these maneuvers. The following obstetric grips/Leopold's maneuvers are carried out:
Fundal Grip (Leopold's First Maneuver)
This is conducted while facing the patient's face. This grip helps the clinician to identify which of the fetal poles (head or breech) is present at the fundus. The fundal area is palpated by placing both the hands over the fundal area. Palpation of broad, soft, irregular mass is suggestive of fetal legs and/or buttocks, thereby pointing towards cephalic presentation. Palpation of a smooth, hard, globular, ballotable mass at the fundus is suggestive of fetal head and points towards breech presentation.
Lateral Grip (Leopold's Second Maneuver)
This grip is also conducted while facing the patient's face. The hands are placed flat over the abdomen on the either side of the umbilicus. Lateral grip helps the clinician in identifying the position of fetal back, limbs and shoulder in case of vertex or breech presentation. The orientation of the fetus can be determined by noting whether the back is directed vertically (anteriorly, posteriorly) or transversely. In case of transverse lie, hard, round, globular mass suggestive of fetal head can be identified horizontally across the maternal abdomen.15
Figs 1.10A and B: Different positions with occipitoanterior position Abbreviations: LOA, left occiput anterior; LOP, left occiput posterior; LOT, left occiput transverse; ROA, right occiput anterior; ROP, right occiput posterior; ROT, right occiput transverse
Figs 1.11A to D: Obstetric grips. (A) First Leopold's maneuver; (B) Second Leopold's maneuver; (C) Third Leopold's maneuver; (D) Fourth Leopold's maneuver
The fetal back can be identified as a smooth curved structure with a resistant feel. The position of the fetal back on the left or right side of the uterus would help in determining the position of the presenting part. The fetal limbs would be present on the side opposite to the fetal back and present as small, round, knob-like structures. After identifying the back, the clinician should try to identify the anterior shoulder, which forms a well-marked prominence just above the fetal head.16
Pelvic Grips
These include two maneuvers: first pelvic grip (Leopold's fourth maneuver) and second pelvic grip (Leopold's third maneuver)
Second pelvic grip (Pawlik's grip) or third Leopold's maneuver: This examination is done while facing the patient's face. The clinician places the outstretched thumb and index finger of the right hand keeping the ulnar border of the palm on the upper border of the patient's pubic symphysis. If a hard globular mass is gripped, it implies vertex presentation. A soft broad part is suggestive of fetal breech. If the presenting part is not engaged, it would be freely ballotable between the two fingers. If the presenting part is deeply engaged, the findings of this maneuver simply indicate that the lower fetal pole is in the pelvis. Further details would be revealed by the next maneuver. In case of transverse presentation the pelvic grip is empty. Normally, the size of head in a baby at term would fit in the hand of the examining clinician.
First pelvic grip (Fourth Leopold's maneuver): The objective of this step is to determine the amount of head palpable above the pelvic brim in case of a cephalic presentation. First pelvic grip is performed while facing the patient's feet. Tips of three fingers of each hand are placed on the either side of the midline in downwards and backwards direction in order to deeply palpate the fetal parts present in the lower pole of the uterus. The fingers of both the hands should be placed parallel to the inguinal ligaments and the thumbs should be pointing towards the umbilicus on both the sides. In case of vertex presentation, a hard, smooth, globular mass suggestive of fetal head can be palpated on pelvic grip. In case of breech presentation, broad, soft, irregular mass is palpated.
In case of cephalic presentation, the following need to be assessed: precise presenting part; fetal attitude and engagement of the fetal head. The fetal attitude or the amount of flexion of the fetal head can be evaluated by assessing the relative position between the sinciput and occiput (Fig. 1.12). In case of a fully flexed fetal head the sinciput can be palpated way above the occiput. As the amount of flexion of the fetal head reduces, the sinciput and occiput can be palpated at almost equal levels.
If the fingers of the palpating hands appear to converge below the fetal head, the fetal head is most likely free floating and not engaged. However, if the fingers of the palpating hand appear to diverge, the head is most likely engaged (Figs 1.13A and B).
Auscultation of Fetal Heart
The fetal wellbeing is usually assessed by listening to the fetal heart. The auscultation of fetal heart will also give some idea regarding the fetal presentation and position. The region of maternal abdomen where the heart sounds are most clearly heard would vary with the presentation and extent of descent of the presenting part (Fig. 1.14). The fetal heart is most easily heard by listening over the back of the fetus. The fetal heart rate can be monitored either through electronic fetal monitoring, using an external fetal monitor or through intermittent auscultation, using a Doppler instrument or Pinard's fetoscope or even an ordinary stethoscope. Instruments utilizing Doppler instruments can be commonly used for detecting fetal heart sounds by 10 weeks. Cardiac activity can be visualized as early as five menstrual weeks using real-time ultrasound with a vaginal transducer. Normal fetal heart rate varies from 110 beats/minute to 160 beats/minute with the average rate being about 140 beats/minute. The fetal heart sounds appear as the ticking of a watch when heard from under the pillow.
Auscultation of fetal heart rate is particularly important in cases whether the woman is unable to perceive the fetal movements. To make sure that the clinician is not accidentally listening to mother's heart instead of fetal heart, the maternal pulse must also be simultaneously palpated. In normal cases, the fetal heart rate must be auscultated as described next.
Normal cases: During the first stage of labor; every 30 minutes, followed by every 15 minutes during the second stage of labor.
High-risk cases: In high-risk cases (e.g. preeclampsia), the fetal heart rate must be auscultated every 15 minutes during first stage and every 5 minutes during the second stage of labor.
VAGINAL EXAMINATION
Routine vaginal examination is not required in the antenatal period. Vaginal examination may be required for confirmation of the signs of pregnancy such as Hegar's sign, Chadwick's and Jacquemier's sign.17
Figs 1.13A and B: Checking the engagement of fetal head on fourth Leopold's maneuver. (A) Unengaged fetal head; (B) Engaged fetal head
Fig. 1.14: Auscultation of fetal heart Abbreviations: LOA, left occiput anterior; LOP, left occiput posterior; LSA, left sacrum anterior; LSP, left sacrum posterior; ROA, right occiput anterior; ROP, right occiput posterior; RSA, right sacrum anterior; RSP, right sacrum posterior
Vaginal examination may also be required in cases of recurrent vaginal discharge, pelvic pain, suspected labor or ectopic pregnancy. Vaginal examination assumes importance in labor where the palpation of sagittal sutures and fontanels through the open cervix helps in evaluation of the baby's position and the amount of descent of the fetal presenting part. Vaginal examination has been described in details in Chapter 3.
Per Speculum Examination
Per speculum examination can help in evaluation of the following parameters: checking the presence of any discharge or lesions; to note the color and consistency of cervix; and to obtain cervical samples for testing.
Pelvic Examination
Since the routine antenatal pelvic examination does not accurately assess gestational age, nor does it accurately predict preterm birth or cephalopelvic disproportion, it is not recommended in routine clinical practice.
FURTHER READINGS
- American College of Obstetricians and Gynecologists Committee on Gynecologic Practice. ACOG Committee Opinion No. 483: Primary and preventive care: periodic assessments. Obstet Gynecol. 2011; 117(4): 1008-15.
- Committee on Nutritional Status during Pregnancy and Lactation, Institute of Medicine, National Academy of Science. “Dietary intake during pregnancy”. Nutrition during pregnancy: Part I: Weight gain, Part II: Nutrient supplements. Washington DC: National Academy Press; 1990.
- National Institute for Clinical Excellence. (NICE, 2008). Antenatal care: Routine care for the healthy pregnant woman. [online] Available from www.nice.org.uk/nicemedia/pdf/CG062NICEguideline.pdf [Accessed November, 2014].
- Sharma R Revision of Prasad's social classification and provision of an online tool for real-time updating. [online] Available from: www.prasadscaleupdate.weebly.com [Accessed November, 2014].