Intrauterine growth pattern in Butajira HDSS, Southern Ethiopia: BUNMAP pregnancy cohort

Abstract

Background: Abnormal fetal growth pattern during pregnancy including excessive fetal size and intrauterine growth restrictions are the major determinants for perinatal outcomes and postnatal growth. Ultrasonography is a useful tool in monitoring fetal growth for appropriate care and interventions. However, there are few longitudinal studies using serial ultrasonography in low and middle-income countries. Moreover, the reference charts used for fetal growth monitoring in low-income countries comes from high income countries with distinct population features. Therefore, the purpose of this study was to evaluate the intrauterine growth pattern of the fetus using serial ultrasonography.

Methods: We conducted a prospective community-based cohort study from March 2018 to December 2019. Pregnant women with gestational age of 24 weeks or below living in the Butajira HDSS were enrolled. We followed the pregnant women until delivery. Serial ultrasound measurements were taken, and fetal weight was estimated using the Hadlock algorithm based on biparietal diameter, head circumference, abdominal circumference, and femur length. The z-scores and percentiles of biometric measurements were calculated and compared to the INTERGROWTH-21^st International Standards for Fetal Growth.

Results: We reviewed a total of 2055 ultrasound scans and 746 women who fulfill the inclusion criteria were involved". We found similar distribution patterns of biometric measurements and estimated fetal weight compared to the previous study done in Ethiopia, the WHO and INTERGROWTH-21^st references. In our study, the 5^th,50^th and 95^th percentiles of estimated fetal weight distribution have a similar pattern to the WHO and INTERGROWTH-21^st charts. The 50^th and 95^th percentile had also a similar distribution pattern with the previous study conducted in Ethiopia. We found that 10% of the fetus were small for gestational age (below the 10^th percentile) based on the Z-score of estimated fetal weight.

Conclusion: Our study evaluated the fetal growth patterns in rural community of Ethiopia using serial ultrasound biometric measurements. We found similar IUG patterns to the WHO and INTERGROWTH-21^st reference standards as well as the previous study conducted in Ethiopia.

Keywords: BUNMAP; Cohort study Ethiopia; Fetal growth; Growth pattern; Intrauterine growth; Longitudinal study; Ultrasound.

Fig. 1

Pregnant women enrolled and retained in the final analysis of the BUNMAP cohort, Butajira Ethiopia 2018–2019. BUNMAP, Butajira Nutrition, Mental health, and Pregnancy; U/S, ultrasound

Fig. 2

Estimated fetal weight (gm) by percentiles (14–38 weeks), Butajira Ethiopia 2018–2019. Distribution of the 5^th,10^th,50^th, 90^th, and 95^th percentiles of estimated fetal weight, n = 2055 observations

Fig. 3

Distribution of the 5^th, 50^th and 95^th percentiles for estimated fetal weight for gestational ages 22 to 38 weeks. Selected percentiles taken from WHO study [6], INTERGROWTH-21^st study [8], Butajira-Ethiopia (current study) and Adamitulu-Ethiopia study [10]

Fig. 4

Z-score of estimated fetal weight, Butajira Ethiopia, 2018–2019. The Z-score distribution ranged from -3.33 to 2.99. n = 1,531 observations for the gestational age ≥ 22 weeks included in the analysis

Fig. 5

Fetal anthropometric measurements by percentiles and gestational age, Butajira Ethiopia, 2018–2019. Distributions of the 5^th, 50^th and 95^th percentiles of fetal biometrics, n = 2,055 observations for the gestational age 14–38 weeks. BPD, Biparietal diameter; HC, Head circumference; AC, Abdominal circumference; FL, Femur length