Perinatal outcomes in uncomplicated late preterm pregnancies with borderline oligohydramnios

Abstract

Purpose: The purpose of this study is to determine the adverse perinatal outcomes in uncomplicated late preterm pregnancies with borderline oligohydramnios.

Methods: A total of 430 pregnant women with an uncomplicated singleton pregnancy at a gestational age of 34 + 0–36 + 6 weeks were included. Borderline oligohydramnios was defined as an amniotic fluid index (AFI) of 5.1–8 cm, which was measured using the four-quadrant technique. Adverse perinatal outcomes were compared between the borderline and normal AFI groups.

Results: Approximately 107 of the 430 pregnant women were borderline AFI, and 323 were normal AFI. The demographic and obstetric characteristics were similar in both groups. Delivery <37 weeks, cesarean delivery for non-reassuring fetal heart-rate testing, meconium-stained amniotic fluid, Apgar 5 min <7, transient tachypnea of the newborn, respiratory distress syndrome, neonatal intensive care unit, and hyperbilirubinemia were not statistically different between the groups (p = .054, p = .134, p = .749, p = 0.858, p = .703, p = .320, p = .185, and p = .996, respectively). Although gestational age was full-term, induction of labor rates were significantly higher in the borderline AFI group (p = .040). In addition, fetal renal artery pulsatility index pulsatility index (PI) was significantly lower in the borderline AFI group than in the normal AFI group (p = .014).

Conclusion: Our results indicated that borderline AFI was not a risk for adverse perinatal outcomes in uncomplicated, late preterm pregnancies.

Keywords:

• Adverse perinatal outcomes
• borderline oligohydramnios
• fetal renal artery PI
• late preterm pregnancies

Disclosure statement

All authors declare that they have no conflicts of interest

Funding

This study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.