Intrapartum fetal heart rate pattern in oligohydramnios

It was the aim of this study to examine intrapartum fetal heart rate (FHR) patterns in oligohydramnios.

Subjects comprised 24 singleton pregnant women diagnosed with oligohydramnios and 470 controls. FHR patterns were analyzed at the end of the first stage and throughout the whole second stage of labor. Numbers of variable deceleration (VD), early deceleration (ED), late deceleration (LD) and prolonged deceleration (PD) per contraction were counted.

Frequencies of decelerations in oligohydramnios and controls were 5.4 +/- 14.5 and 2.0 +/- 6.6% for ED, 0.0 and 0.4 +/- 2.5% for LD, 17.6 +/- 20.6 and 12.2 +/- 13.3% for VD, and 1.8 +/- 3.7 and 0.8 +/- 3.0% for PD in the first stage of labor. In the second stage, frequencies were as follows: 5.1 +/- 10.5 and 1.5 +/- 6.1% for ED, 0.5 +/- 1.7 and 1.0 +/- 4.4% for LD, 30.1 +/- 22.0 and 43.9 +/- 29.3% for VD, and 29.3 +/- 33.2 and 12.6 +/- 22.5% for PD.

In cases of oligohydramnios, ED occurred frequently from the first stage of labor. In the second stage of labor, the frequency of PD was extremely high and the frequency of VD was low.