Sonographic evaluation of amniotic fluid index in normal pregnant women in South Eastern Nigeria.

Abstract

Background: Amniotic fluid index (AFI) is one of the key measures in obstetric ultrasound used for assessing amniotic fluid volume. Objective: To assess AFI in normal pregnancies and its relationship with gestational age and possible foetal anomalies in our local setting. Materials and Methods: A cross-sectional prospective survey was conducted on pregnant women between 20 and 40 weeks of gestational age with normal pregnancies who were referred for antenatal scan. Data were processed on SPSS version 25 and analyzed statistically using both descriptive and inferential statistics. The level of statistical significance was set at p < 0.05. Results: The AFI showed a gradual increase with gestational age.  The mean AFI rises from 14.55 in weeks 20 to 24. Then, to 15.06 in weeks 35-40. The mean AFI in the second trimester was 14.62 cm. It was slightly lower than the third-trimester mean of 14.87 cm. At a p-value of 0.604, the difference between trimesters was not statistically significant, suggesting that AFI levels remained stable across these gestational periods. The correlation between amniotic fluid volume and gestational age showed that the correlation coefficient (r) was 0.114, indicating a very weak positive correlation between amniotic fluid volume and gestational age. Conclusion: The amniotic fluid index showed a mild, gradual increase with gestational age. Although not statistically significant across trimesters, AFI remained relatively stable, supporting normal fetal development with no signs of underlying anomalies in the study.