Comparison between AFI and DVP in predicting adverse neonatal respiratory outcomes in women with prolonged pregnancy undergoing induction of labour

Abstract

Terms of post term and prolonged pregnancy are poorly defined. Prolonged pregnancy is considered as menstrual age ranged from 41 to 41 6/7 weeks of gestation, while a pregnancy beyond 42 0/7 weeks is defined postterm. Frequently, postterm pregnancy is associated with oligohydramnios. It is probably related to a decrease in placental function and/or in fetal renal perfusion with reduction of urine production. Post term pregnancy is associated with an increased risk of fetal and neonatal mortality and morbidity as well as an increased maternal morbidity. Oligohydramnios complicates 0.5% to 8% of pregnancies, and management and prognosis depend on gestational age and associated obstetric complications. Outcomes are worse with earlier or more severe oligohydramnios (e.g., anhydramnios). Etiologies include preterm premature rupture of membranes (PPROM) ig., fetal abnormalities (especially of the genitourinary tract), and placental insufficiency. The limitations of direct invasive measurement of amniotic fluid volume led to the use of ultrasound for amniotic fluid volume estimation, most often carried out by assessment of the amniotic fluid index (AFI) or the single deepest vertical pocket (SDP)technique. However there is no clear consensus on the best method to assess amniotic fluid adequacy. Both techniques are similarly poor predictors, with AFI overestimating and SDP underestimating actual low amniotic fluid volumes. A Cochrane review concluded that the use of AFI increases the rate of diagnosis of oligohydramnios and the rate of induction of labor without improving peripartum outcome.