Comparison Of Fetal Biometry In Obese Versus Non Obese Nulliparous Pregnant Women

Abstract

Background: Maternal obesity is a developing worldwide health issue and has been linked to determine an important change on intrauterine fetal growth pattern. The available literature shows contradictory reports, where some show an overgrowth of the fetus (macrosomia), others show limited or disproportionate fetal growth among obese mothers. The objective of the current research was to compare fetal biometric measures between obese and non-obese nulliparous expectant women as well as to determine how the body mass index (BMI) of the mother affects fetal growth.

Aims: To evaluate the relationship between maternal obesity and fetal growth in nulliparous pregnancies.

Methods: The study was an observational, comparative, cross-sectional research involving 90 nulliparous women who had singleton pregnancies and were aged 20-30 weeks of gestation (45 obese (BMI ≥ 30 kg/m²)  and 45 non-obese(BMI < 30 kg/m²)) with singleton pregnancies. Qualified sonographers took standardized ultrasonographic measurements, such as biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) and estimated fetal weight (EFW). The SPSS 29 version was used to analyze data. Independent samples t-tests were used to compare different groups and calculate descriptive statistics. Correlation and multiple regression were done to establish the correlation between maternal BMI, gestational age and fetal biometric measures. The p-value of less than 0.05 was regarded as significant.

Results: Obese and non-obese groups were subjected to descriptive analysis to determine the distribution of fetal biometric parameters as biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW). The mean values were as below in the group with obesity: BPD = 5.62 +- 0.66 cm, HC = 21.20 +- 1.83 cm, AC = 18.48 +- 1.77 cm, FL = 3.57 +- 0.71 cm, and EFW = 556.20 +- 220.19 g. In the non-obese group, the same means were a little higher: BPD = 5.89 +- 0.79 cm, HC = 21.65 +- 2.69 cm, AC = 19.24 +- 2.76 cm, FL = 4.22 +- 0.69 cm and EFW = 675.11 +- 305.12 g. Descriptive summary shows that all the fetal biometric parameters were greater in the non-obese group, but the level of difference was more eminent in the length of the femur and estimated weight of the fetus.

Conclusion: This research indicates that the larger the maternal BMI among the nulliparous women, the shorter the length of the femur and the lower the estimated fetus weight when the gestational age is controlled. The results indicate that maternal obesity can have a modification in the growth pathways of the fetus and could end up in the possibility of limited or asymmetric development and not necessarily universal macrosomia. These findings highlight the significance of personal fetal growth tracking during pregnancy in obese pregnancies to detect anomalies in normal growths. More extensive, longitudinal and multicentric research to include placenta and metabolite variables is suggested to clarify the mechanisms behind the changes in fetal biometry as a result of obesity.