An Atlas of Neonatology ML Kulkarni
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Nomenclature1

Understanding of proper, and uniform nomenclature is important in classifying newborns, in anticipating problems, for demographic purpose, and interpersonal communication. Below we describe commonly used terms in neonatal/perinatal practice.
 
 
Live Birth
Live birth is complete expulsion or extraction of products of conception from its mother irrespective of duration of pregnancy, which after such separation, breathes or shows any other evidence of life, such as beating of heart, pulsation of the umbilical cord, definite movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached.
 
Fetal Death
Early fetal death (abortion): Death of a fetus having birth weight of less than 500 g, or gestation of less than 22 weeks, or crown-heel length less than 25 cm.
Intermediate fetal death (abortion): Death of fetus having birth weight between 501 and 1000 g, or gestation between 22 and 28 weeks, or crown-heel length between 25 and 35 cm.
Stillbirth (late fetal death): Death of a fetus having birth weight of 1000 g, gestation of more than 28 weeks, or crown-heel length of more than 35 cm.
The terms birth weight and gestation are defined later.
Perinatal period: The perinatal period is most often defined as a period from 28 weeks of gestation through the 7th day after birth—WHO. Other additional definitions include:
  1. 20 weeks of gestation to 7 days after birth,
  2. 20 weeks of gestation to 28 days of life.
Neonatal period: The neonatal period is defined as less than 28 days of life and it may be subdivided into period 1 (Birth to <24 hours), period 2 (24 hours to <7 days), and period 3 (7 to 28 days).
 
Birth Weight Groups
  • Low birth weight (LBW)—birth weight less than 2500 g.
  • High-risk low birth weight (HRLBW)—birth weight less than 2000 g.
  • Very low birth weight (VLBW)—birth weight less than 1500 g.
  • Extremely low birth weight (ELBW)—less than 1000 g.
 
Gestational Age
The duration of gestation is measured from the first day of the last menstrual period (LMP). Gestational age is expressed in completed days or completed weeks.
 
Gestational Groups
  • Preterm—less than 37 completed weeks or less than 259 days.
  • Term—from 37 completed weeks to less than 42 completed weeks or 259 to 294 days.
  • Postterm—more than 42 completed weeks or more than 295 days.
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Birth Weight/Gestational Age Group
Small-for-gestational age (SGA)—Babies with a birth weight of less than 10th percentile for that period of gestation.
Large-for-gestational age (LGA)—Babies with a birth weight greater than 90th percentile for that period of gestation.
Adequate-for-gestational age (AGA)—Babies with a birth weight between 10th and 90th percentile for that period of gestation.
 
Perinatal Period
From 28 weeks of gestation to first 7 completed days (168 hours) of life.
 
Neonatal Period
First 28 days of life. Early neonatal period refers to the first 7 days (168 hours) of life, while late neonatal period signifies the period from more than 7 days to 28 days of life.
 
Perinatal Mortality Rate (PMR)
Perinatal mortality rate (PMR) is defined as late fetal plus early neonatal (first week) deaths of babies weighing more than 1000 g (or 28th weeks of gestation or more) at birth per 1000 total births weighing over 1000 g. Important causes are listed in Table 1.1.
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Table 1.1   Causes of perinatal mortality and their percentage
Causes of death
Percentage
Asphyxia
41.6
Prematurity, low birth weight
17.9
Congenital malformations
6.7
Septicemia
2.4
Respiratory distress syndrome
2.2
Anemia
1.5
Birth trauma
1.2
Multiple factors
11.0
Undetermined
15.5
Source: Ministry of Health and Family Welfare, Govt. of India, 1983.
Table 1.2   Categories of causes of perinatal death
Maternal
Fetal
Infants
Maternal age
<18> 35 yrs
Prematurity
Birth injuries
High parity
SGA
Asphyxia
Maternal anemia
Twins
Infections including tetanus
Toxemia
Congenital malformations
Poor spacing
Hypothermia
Prediabetes or diabetes
Present perinatal mortality is 44.3 per 1000 births (1993)— (Shanti Ghosh) and is 3–4 times more in LBW babies.
 
Extended Perinatal Mortality Rate
Extended PMR is defined as late fetal plus early neonatal deaths weighing more than 500 g at birth per 1000 total births weighing over 500 g
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Neonatal Mortality Rate (NMR)
Neonatal mortality rate (NMR) is defined as neonatal deaths of babies weighing more than 1000 g at birth per 1000 live born infants weighing over 1000 g. Importance of NMR is that it accounts for 60 percent of infant mortality (Table 1.3).
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(Present status, 1991, NMR: 51.1)
Table 1.3   Causes of neonatal mortality
  • Immaturity
  • Birth asphyxia
  • Infections
  • Congenital malformations
  • Others like birth trauma
 
Extended Neonatal Mortality Rate
The extended neonatal mortality rate can be calculated by including babies weighing up to 500 g or more at birth per 1000 live born infants weighing 500 g or more.
3
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Fig. 1.1: Graphical representation of neonatal terminologies
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Infant Mortality Rate (IMR)
Infant mortality rate is the ratio of deaths under 1 year of age in a given year to the total number of live births in the same year, usually expressed as a rate per 1000 live births. Present rate is 74/1000.
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(Source: 1994 Sample Registration System, Registrar General, Govt. of India).
 
Causes
  1. ARI.
  2. Diarrhea.
  3. Under nutrition.
  4. Infections.