ADJUSTING FOR FETAL SEX IN INDIVIDUAL CHARTS TO ASSESSTHE RISK OF INTRAUTERINE GROWTH RETARDATION

Abstract

Introduction: The diagnosis of intrauterine growth restriction in pregnancy is an important consideration in antenatal
care, particularly in low-risk women, but often goes unrecognised. There are now population-based, individualised charts for
the assessment of antenatal growth.
Aim: To determine the effect of changing maternal and fetal characteristics on fetal birth weight in a population of
pregnant women in Kazakhstan.
Materials and Methods: The design of our study was one-stage cross-sectional. Inclusion criteria were: presence of
first-trimester ultrasound screening at 10 - 14 weeks, uncomplicated pregnancy, and singleton pregnancy. Exclusion criteria
were: multiple pregnancies, breech presentation, malposition (transverse, oblique), fetal weight less than 2500 grams and
more than 4000 grams, premature birth, hypertensive states, antenatal fetal death, congenital malformations, hydramnion,
hypamnion, and extragenital pathology.
Results: A total of 3,886 cases of term pregnancies in the cephalic presentation, which ended with a live birth weight of
2,500 to 4,000 grams, were selected for this study. On average, the weight of male newborns was 3440.0 grams and was
greater than that of female newborns (Me 3370.0 grams). And as a function of gestational age, fetal weight became heavier with
each week (p < 0.001). There was also a difference in mean fetal birth weight and uterine fundus height at 37 to 42 weeks
gestation depending on fetal sex (p = 0.042, p = 0.021, p = 0.011, p = 0.002, respectively). An increase in fetal weight of 40.79
grams is to be expected when parity is increased by 1 birth. By linear regression, it was found that with a history of one birth an
increase in fetal weight of 62.05 grams could be expected, with a history of 2 births an increase in fetal weight of 105.92 grams
could be expected and with 3 or more births an increase in fetal weight of 107.91 grams could be expected. We found that an
increase in fetal weight of 79.98 grams should be expected in the 20 - 24-year-old group compared to women under 20 years of
age. And in the 25 – 29-year-old group an increase in fetal weight of 97.63 grams should be expected, in the 30 - 34-year-old
group an increase of 104.22 grams and in the over 35-year-old women an increase of 84.62 grams should be expected. An
increase in fetal weight of 101.98 grams should be expected when gestational age is increased by 1 week. An increase in fetal
weight of 54.14 grams (p < 0.001) should be expected in pregnancies with a male fetus.
Conclusions: Fetal sex affects fetal weight and height at birth and uterine floor height at 37 to 42 weeks' gestation.