Evaluation of normal amniotic fluid volume with sonography in expectant Nigerian women

Background: Due to racial and ethnic differences in Amniotic fluid dynamics and fetal biometry, population-specific reference values for amniotic fluid volume (AFV) are essential for fetal well-being. This study addresses Nigerian women's need for such values.
Objective: To establish gestational age-specific reference ranges for normal AFV using Amniotic Fluid Index (AFI) and Single Deepest Pocket (SDP) in pregnant Nigerian Women to enhance diagnosis of oligohydramnios and polyhydramnios.
Methodology: This was a prospective hospital based cross-sectional analytical study conducted at Benue State University Teaching Hospital (BSUTH), Makurdi from August 2024 to August 2025.Standardized ultrasonography was performed on 250 women with singleton pregnancies between 22 and 40 weeks using a Siemens Sonoline G-50 machine. SPSS version 23 and Microsoft Excel 2007 were used to analyze AFI and SDP measurements at p<0.05.
Results: The mean age of responders was 30.42 ± 3.50 years and BMI was 26.41 ± 3.84 kg/m2. AFI was 16.75 ± 2.66 cm at 22–28 weeks and 17.57 ± 3.08 cm at 29–40 weeks with similar trends for SDP. The association between AFI and SDP was moderate (r = 0.550) with the regression equation AFI = 4.01 + 0.81 × SDP. Percentile analysis showed stable lower limits at late gestation, but more variability at higher percentiles. African populations had mean AFI values which were relatively higher yet clinically acceptable when compared to Western and Asian groups.
Conclusion: We established local AFI and SDP reference values to improve fetal assessment, thus creating a dependable AFV normogram for obstetrics in Nigeria.