The relationship between amniotic fluid index and accuracy of sonographic estimated fetal weight

Abstract

Background: Ultrasound is the gold standard in evaluation of amniotic fluid volume and diagnosis of volume disorders as oligohydramnios and polyhydramnios. While the amniotic fluid may be thought of as an expansion of the foetus extracellular fluid compartment during the first two trimesters of pregnancy, most amniotic fluid is actually produced during the third trimester due to foetal micturition. We hypothesised a link between the amniotic fluid indexes (AFI) and estimated foetal weight (EFW), which might suggest that EFW be considered in amniotic fluid evaluation. Methods: This cross-sectional study was conducted on 75 pregnant cases (Age was >18 years) and carrying singleton pregnancy with GA from 18 weeks to 40 weeks (GA evaluation was based on menstrual history & early US assessment) for 1 year. All participants underwent full history taking, abdominal ultrasonography examination and assessment of amniotic fluid index. Results: The majority of included pregnancies showed cephalic presentation of the fetus. The overall AFI ranged from 2 to 30 cm, with a mean value of 17.2 (SD, 7.4) cm and a median value of 18 (IQR, 11) cm. The majority of included pregnancies showed a normal BPP. There was no significant association between AFI and EFW for all categories of gestational age, except in the 27-29 week's group. Conclusions:The AFI and EFW numbers found in this research fell within a certain range. Nevertheless, these variables showed no statistically meaningful correlation with one another. Inferring from that, it seems unlikely that either measure is worth focusing on when the other is subject to fluctuation.