Amniotic fluid index (AFI) in post-dates pregnancy

ABSTRACT

This is a prospective evaluation of the relationship between the amniotic fluid index (AFI) and perinatal outcome in 55 patients managed in the Obstetric Unit at the UHWI. The subjects had an otherwise uncomplicated pregnancy and early confirmation of gestational age by ultrasound. Forty-two patients had delivered by 41 weeks and the remaining thirteen by 42 weeks. The gravid abdomen was divided into four quadrants, using real-time ultrasound with a 3.5 Mhz transducer, the largest pocket of amniotic fluid in each quadrant was measured and their sum totalled to arrive at the amniotic fluid index. The pregnancies were managed without knowledge of this evaluation. Perinatal outcome was assessed by the presence of meconium stained liquor and its aspiration, intrapartum fetal distress, low APGAR scores at delivery and the need for admission to the nursery. AFI in this study ranged from 2.8 cm to 22.6 cm. The mean for 41 weeks was 13.52 +/- 4.6 cm and 42 weeks 9.93 +/- 4.37 cm. Oligohydramnios was noted in four patients, AFI less than 5.3 cm. Two of these cases developed intrapartum fetal distress and had caesarian section. All four babies were admitted with meconium aspiration and one died from this complication. Evaluation of the AFI can be useful in the monitoring of post-dates pregnancy. (AU)