Biophysical profile with amniotic fluid volume assessments. Amniotic fluid index vs single deepest pocket technique during modified biophysical profile: a randomized clinical trial. A randomized clinical trial of the intrapartum assessment of amniotic fluid volume: amniotic fluid index versus the single deepest pocket technique. A randomised comparison between amniotic fluid index and maximum pool depth in the monitoring of post-term pregnancy.
To compare the amniotic fluid index (AFI) with the single deepest pocket technique along with the other components of the biophysical profile (BPP) in predicting an adverse pregnancy outcome.
                Prospective, randomized trial of amniotic fluid assessment by AFI or single deepest pocket during a BPP. Cesarean delivery for fetal distress was the primary outcome evaluated.
                The AFI was used in 273 pregnancies and the single deepest pocket in 264. The AFI significantly increased the number of pregnancies labeled as oligohydramnios, 102 women (38%) compared with 46 women (17%; P <.001), odds ratio (OR) = 2.84, 95% confidence interval 1.90-4.25 in the single deepest pocket group. There was no difference in the number of women with oligohydramnios in the AFI group, 16 of 102 (16%), undergoing a cesarean delivery for fetal intolerance of labor compared with the single deepest pocket group, 6 of 46 (13%; P =.676). More women with normal fluid by the AFI method (AFI > 5), 20 of 170 (12%), underwent a cesarean delivery for fetal distress than the women with normal fluid by the single deepest pocket technique (2 cm x 1 cm pocket present) group, 12 of 218 (6%; P =.037, OR = 2.22, 95% confidence interval 1.05-4.70).
                The AFI offers no advantage in detecting adverse outcomes compared with the single deepest pocket when performed with the BPP. The AFI may cause more interventions by labeling twice as many at-risk pregnancies as having oligohydramnios than with the single deepest pocket technique. The purpose of this study was to determine the superior technique, if either, of the amniotic fluid index (AFI) vs the single deepest pocket technique in predicting an adverse pregnancy outcome among high-risk patients undergoing antenatal testing.
                Patients having modified biophysical profile (nonstress test plus sonographic estimation of amniotic fluid) were randomized to either have AFI or determination of the presence or absence of a 2 x 1-cm single deepest pocket.
                Between January of 1997 and December of 2001, 1080 women were randomized with 530 women in the AFI arm, and 558 in the 2 x 1 pocket arm. The maternal demographics and prenatal complications were similar between groups. Significantly more patients were identified as having oligohydramnios using AFI (17%) compared with using 2 x 1 pocket (10%) ( P =.002). The overall rate of cesarean section for nonreassuring fetal heart rate (FHR) tracing was 3.8% (30 cases, with 16 cases in the AFI-monitored, and 14 cases in the 2 x 1 pocket-monitored groups, respectively, P =.608). Logistic regression analysis showed no difference between the groups with respect to the ability to identify patients who underwent cesarean section for nonreassuring FHR tracing during labor ( P =.999). The umbilical artery pH <7.1 ( P =.688) and admission to the newborn intensive care unit were also comparable between groups.
                During antepartum fetal surveillance, use of single deepest pocket compared with amniotic fluid index is associated with a significantly lower rate of suspected oligohydramnios. The purpose of this study was to determine whether an intrapartum assessment of amniotic fluid identifies a pregnancy that is at risk for an adverse outcome.
                Parturients who were admitted for delivery were assigned randomly to have the amniotic fluid assessed either by amniotic fluid index or by the presence of a 2 x 1 pocket.
                The amniotic fluid index was obtained in 499 pregnancies, and the 2 x 1 technique was performed in 501. Oligohydramnios was diagnosed in 25% of amniotic fluid index pregnancies versus 8% with the use of the 2 x 1 pocket technique (P <.001). Both techniques failed to identify patients who underwent an amnioinfusion for fetal distress (P=.864) or who experienced variable (P=.208) or late decelerations (P=.210) that influenced delivery, fetal distress in labor (P=.220), caesarean delivery for fetal distress (P=.133), and admission to neonatal intensive care unit (P=.686).
                Neither the amniotic fluid index nor the 2 x 1 pocket technique that was undertaken as a fetal admission test identifies a pregnancy that is at risk for an adverse outcome. To compare the impact of two different ultrasound methods for assessing amniotic fluid volume on the incidence of obstetric interventions in post-term pregnancies.
                A prospective randomised controlled trial.
                Liverpool Women's Hospital.
                Five hundred women with singleton, uncomplicated pregnancies with gestational age > or = 290 days.
                Random allocation to fetal monitoring by either: 1. amniotic fluid index and computerised cardiotocography, or 2. maximum pool depth and computerised cardiotocography.
                Primary: caesarean section. Secondary: the number of abnormal monitoring tests, induction of labour, intrapartum management and neonatal outcome.
                The number of abnormal amniotic fluid indices was significantly higher than the number of abnormal maximum pool depths (10% vs 2.4%; OR 4.51, 95% CI 1.82-11.21; P = 0.0008) which resulted in more inductions for abnormal post-term monitoring in the amniotic fluid index group (14.8% vs 8.4%; OR 1.89; 95% CI 1.07-3.33; P = 0.0362) and more intrapartum electronic fetal monitoring (94.4% vs 88.4%; OR 2.21; 95% CI 1.13-4.29; P = 0.0255). There were no other statistically significant differences in outcomes related to labour and delivery, but there was a trend towards more caesarean sections in the amniotic fluid index group (18.8% vs 13.2%), in particular caesarean sections for fetal distress (8% vs 4%). There were no perinatal deaths and no statistically significant differences in perinatal outcome between the two groups.
                Published reference ranges for amniotic fluid index overestimate the number of abnormal results in post-term pregnancies. Their use, when compared with maximum pool depth, is likely to increase the number of obstetric interventions with, as yet, an uncertain impact on perinatal mortality and morbidity. It is possible that antepartum fetal assessment in pregnancies where the risk of adverse perinatal outcome is very low may cause, rather than prevent morbidity.
The single deepest vertical pocket measurement in the assessment of amniotic fluid volume during fetal surveillance seems a better choice since the use of the amniotic fluid index increases the rate of diagnosis of oligohydramnios and the rate of induction of labor without improvement in peripartum outcomes. A systematic review of the diagnostic accuracy of both methods in detecting decreased amniotic fluid volume is required.