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Published on: November 20, 2015
Gestational age--the most important factor of neonatal ponderal index
Damir Roje1, Ivo Banovic, Banovic Ivo
1Department of Obstetrics and Gynecology, University Hospital Split, Spinciceva 1, 21000 SPLIT, Croatia, Europe. damir@kbsplit.hr
Insights
The ponderal index (PI) is a key indicator of fetal growth, with gestational age being its primary determinant. Sex and maternal parity influence PI in neonates after 37 weeks gestation.
Area of Science:
- Neonatal anthropometry
- Fetal growth assessment
- Perinatology
Background:
- The ponderal index (PI) is an anthropometric tool for diagnosing impaired fetal growth, reflecting infant nutritional status.
- Fetal growth is influenced by ethnicity, geography, and socioeconomic factors, necessitating localized standards.
- Neonatal PI standards are crucial for accurate assessment of fetal development.
Purpose of the Study:
- To establish reference standards for neonatal ponderal index (PI).
- To evaluate the impact of gestational age, sex, and maternal parity on neonatal PI.
- To provide accurate anthropometric data for assessing fetal growth in a specific population.
Main Methods:
- Retrospective analysis of data from 5798 newborns (24-42 weeks gestation) from singleton pregnancies.
- Inclusion of preterm infants from a 10-year period to ensure adequate sample size per gestational week.
- Exclusion of stillbirths and infants with congenital malformations; Caucasian mothers only.
Main Results:
- Neonatal PI demonstrated a linear correlation with gestational age from 24 to 39 weeks, followed by a plateau.
- Gestational age was the most significant factor influencing neonatal PI.
- Sex and parity impacted PI only in neonates after 37 weeks gestation, with females and multiparous infants showing higher PI.
Conclusions:
- Gestational age is the predominant factor in determining neonatal ponderal index.
- The influence of sex and maternal parity on PI is significant only in term neonates (after 37 weeks gestation).
- Established PI standards aid in the accurate evaluation of fetal growth and nutritional status.
Abstract:
Ponderal index (fetal weight in grams X 100 / (fetal length in centimeters)3) (PI) is one of the anthropometric methods used to diagnose impaired fetal growth. Irrespective of the infant's position on the growth-weight-for-gestational age charts, PI is low in malnourished infants and high in obese ones. As fetal growth is affected by ethnicity, geographic location and socioeconomic status, we developed standards for neonatal PI, and assessed the effects of gestational age, sex and maternal parity. Data on 5798 newborns from singleton pregnancies born in the Department of Gynecology and Obstetrics, Split University Hospital, were retrospectively analyzed. Over a 15-month period in 2000/2001, 5596 newborns from 24 to 42 weeks of gestation were born. The other 202 newborns, born from 24 to 34 weeks of gestation in the ten year period, 1990-1999, were added because of the small number of preterm infants; ensuring a minimum of 30 to fill up at least infants in each gestational week. All mothers were of Caucasian origin. Stillbirths and fetuses with congenital malformations were excluded. The 10th, 50th and 90th percentiles, mean values with standard deviation of PI and the 10th, 50th, and 90th percentiles of birth weight and birth length are presented separately at weekly intervals. PI showed linear correlation with gestational age from 24 to 39 weeks, after witch the data plateaued. Sex and parity had no impact on PI in infants born between 24 and 37 weeks. Analysis of variance revealed PI to be significantly higher in female than in male newborns, and in multiparous than in nulliparous infants after 37 weeks of gestation. In conclusion, gestational age is the most important factor of neonatal PI. The effects of sex and parity on PI should only be considered in term neonates.