Patterns of fetal growth in a rural Indian cohort and comparison with a Western European population: data from the Pune maternal nutrition study.

Objective: The purpose of this study was to describe fetal size on sonography in a rural Indian population and compare it with those in European and urban Indian populations. Methods. Participants were from the Pune Maternal Nutrition Study of India. Fetal growth curves were constructed from serial ultrasound scans at approximately 18, 30, and 36 weeks' gestation in 653 singleton pregnancies. Measurements included femur length (FL), abdominal circumference (AC), biparietal diameter (BPD), and occipitofrontal diameter, from which head circumference (HC) was estimated. Measurements were compared with data from a large population-based study in France and a study of urban mothers in Vellore, south India.

Results: Fetal AC and BPD were smaller than the French reference at 18 weeks' gestation (-1.38 and -1.30 SD, respectively), whereas FL and HC were more comparable (-0.77 and -0.59 SD). The deficit remained similar at 36 weeks for AC (-0.97 SD), FL (-0.43 SD), and HC (-0.52 SD) and increased for BPD (-2.3 SD). Sonography at 18 weeks underestimated gestational age compared with the last menstrual period date by a median of -1.4 (interquartile range, -4.6, 1.8) days. The Pune fetuses were smaller, even at the first scan, than the urban Vellore sample.

Conclusions: Fetal size was smaller in a rural Indian population than in European and urban Indian populations, even in mid pregnancy. The deficit varied for different fetal measurements; it was greatest for AC and BPD and least for FL and HC.