Discussion
Recognition of polyhydramnios is of benefit as it allows identification of pregnancies that may be at increased risk of adverse outcomes. Once polyhydramnios is identified, patients need a thorough evaluation as it is associated with an increased frequency of both maternal and fetal complications.11 Chamberlain cited an increased rate of perinatal morbidity and mortality among patients with hydramnios.6
In reviewing the adverse outcomes in pregnancies complicated by polyhydramnios, we found the overall incidence of polyhydramnios to be 1.8% in our population. Of those who were included in our study group, 80% were considered to have mild polyhydramnios, 17.6% of the cases were considered moderate, and 2.4% were considered severe. This is similar to Barnhart’s study, which noted polyhydramnios in 1.7% of 2,730 pregnancies.12
A demographic analysis showed that polyhydramnios was more common in older gravida. However, parity had no significant relationship to polyhydramnios. This was consistent with Mariam’s study.12 However, Biggo et al. found a significant relationship between both rising maternal age and parity in polyhydramnios.13
The association between diabetes and polyhydramnios is well known.14 A commonly supported theory is that increased amniotic fluid volume in diabetic pregnancies could be a result of maternal hyperglycemia which, in turn, produces fetal hyperglycemia and osmotic diuresis. It has consistently been reported that approximately 15% of pregnancies complicated by polyhydramnios occur in diabetic women.15 This figure was consistent with our study. We found that 73 of our polyhydramnios patients (15.3%) were diabetic, including 59 who were being treated for gestational diabetes or were on a medically supervised diet, Twelve had gestational insulin-treated diabetes. Only two patients had pre-existing diabetes mellitus.
The mean gestational age at delivery was 38.2 ± 1.4 weeks. There was no significant increase in preterm delivery as most preterm deliveries were noticed in case of severe polyhydramnios due to uterine overdistension or fetal anomalies. These comprised only 2.5% of the study group. This result was consistent with Many, whose study showed no increased rate of preterm delivery with polyhydramnios.16
The mode of delivery was also influenced by polyhydramnios, with a higher proportion of Caesarean deliveries as compared with those mothers who had a normal volume of amniotic fluid. We found a significantly elevated Caesarean delivery rate in the polyhydramnios group, which had a 24% rate compared to 10.6% in the control group.
In our study, polyhydramnios had an impact on perinatal outcomes, the occurrence of fetal macrosomia and fetal congenital anomalies, and SCBU admissions of neonates. The prevalence of anomalies was 8.1%, which was fairly comparable with other large series studies. This confirms reports of greater anomaly risks that occur with worsening polyhydramnios.17 Dashe reported in his study of polyhydramnios and anomaly detection that 11.0% of the neonates in his study had fetal anomalies.8
In our study, the high incidence of macrosomia associated with polyhydramnios was consistent with several others studies, and showed a correlation between large-for-gestational-age infants and polyhydramnios.18