Association of Fetal Growth Rate in First Trimester and Being Large or Small for Gestational Age

Abstract

Objective:      To evaluate the association of fetal growth rate in first trimester and fetal birth weight.

Materials and Methods:        The prospective cohort study was performed at the department of Obstetrics and Gynecology, Bhumibol Adulyadej Hospital, Bangkok, Thailand. Fetal growth rate was measured by ultrasound twice in first trimester. First Crown Rump Length (CRL) ultrasound was measured at first antenatal care (ANC) and second CRL ultrasound was at four weeks later. Delta CRLs was calculated and divided into 3 groups: larger than expected, smaller than expected and equal as expected. Patients were followed until delivery. Fetal birth weights were stratified and labeled as large for gestational age (LGA), small for gestational age (SGA) and appropriate for gestational age (AGA) by birth weight percentile at gestational age at delivery. Fetal growth rate in first trimester and fetal birth weight were analyzed.

Results:            114 pregnant women were recruited. 59 fetuses were equal as expected (51%), 43 fetuses were smaller than expected (38%) and 12 fetuses were larger than expected (11%). The delta CRLs were significantly associate to fetal birth weights (P = 0.000). Diabetic mellitus and hypertension were not significantly associated to fetal birth weights.

Conclusion:    Fetal growth rate in first trimester was significantly associated to fetal birth weight.