Obstetric outcomes of isolated oligohydramnios during early-term, full-term and late-term periods and determination of optimal timing of delivery

Window to the Womb: Amniotic Fluid and Postnatal Outcomes

Amniotic fluid volumes are tightly regulated, and amniotic fluid derangement can indicate maternal complications or fetal abnormalities. Ultrasound estimate of amniotic fluid provides a tool to evaluate the maternal-fetal-placental interface in real-time. Oligohydramnios and polyhydramnios are associated with adverse maternal and neonatal outcomes. Oligohydramnios is associated with adverse maternal and neonatal outcomes including cesarean delivery, operative vaginal delivery, induction of labor, postpartum hemorrhage, small for gestational age neonate, intrauterine demise, neonatal death, NICU admission, and APGAR less than 7 at. 5 minutes of life Polyhydramnios is associated with adverse outcomes including cesarean delivery, induction of labor, placental abruption, shoulder dystocia, cord prolapse, postpartum hemorrhage, intrauterine fetal demise, NICU admission, neonatal death, APGAR less than 7 at 5 minutes of life, large for gestational age neonate, and respiratory distress syndrome. Therefore, Amniotic fluid should be evaluated when maternal or fetal well-being is in question.

Optimizing Term Delivery and Mode of Delivery

Full-term deliveries are defined as occurring between 39 weeks and 40 weeks and 6 days. Because contemporary research suggests improved outcomes with delivery in the term period compared with the early term period, nonindicated delivery should be pursued no earlier than 39 weeks. There are, however, multiple medical, obstetric, and fetal indications for delivery before 39 weeks, and the obstetric provider must weigh the risks and benefits of delivery versus expectant management on both the mother and fetus. This review serves to provide a basic framework of evidentiary support toward optimizing the term delivery.

The association between isolated oligohydramnios at term and placental pathology in correlation with pregnancy outcomes

INTRODUCTION

Isolated term oligohydramnios (ITO) is an obstetrical complication of which the etiology, management, and clinical importance are controversial. In attempt to deepen our understanding, we aimed to study placental pathology and pregnancy outcomes in pregnancies complicated by ITO.

MATERIALS AND METHODS

- Maternal demographics, neonatal outcomes, and placental histopathology reports of all pregnancies complicated by ITO at 37^0/7 to 41^0/7 weeks were reviewed. Excluded were cases complicated by hypertensive disorders, intrauterine fetal growth restriction, placental abruption, and deliveries of undiagnosed small for gestational age neonates. Results were compared between the ITO group and a control group matched for gestational age and mode of delivery. Placental lesions were classified according to the current "Amsterdam" criteria. Composite adverse neonatal outcome was defined as one or more of the following early complications: neonatal intensive care unit admission, sepsis, blood transfusion, phototherapy, respiratory morbidity, cerebral morbidity, necrotizing enterocolitis, or death.

RESULTS

The study group included 108 patients with ITO that were compared to matched controls. Placentas from the ITO group were characterized by higher rates of placental weights <10th centile (p < 0.001), abnormal cord insertion (p < 0.001), and maternal vascular malperfusion (MVM) lesions (p < 0.001). Neonates from the ITO group had lower birth weights (p < 0.002), and worse composite adverse neonatal outcome (p = 0.028) compared to controls.

CONCLUSION

- The current study demonstrates higher rates of placental MVM lesions, and worse neonatal outcome in pregnancies complicated by ITO. These novel findings suggest that ITO should be seen as part of the "placental insufficiency" spectrum.

Maternal and perinatal outcomes of induction of labor in oligohydramnios at term-a retrospective cohort study

Objective: To evaluate the maternal and perinatal outcomes of labor induction in women at term with oligohydramnios.Methods: A retrospective cohort of women with a singleton pregnancy, who had oligohydramnios at or beyond term (37-42 weeks) and underwent induction of labor for oligohydramnios were studied. Antenatally diagnosed fetal anomalies and intrauterine fetal demise were excluded. The women were categorized into two groups: 1) women with isolated oligohydramnios (n = 166) and 2) women with oligohydramnios associated with other maternal or fetal complications (n = 43). Maternal and perinatal outcomes were collected from the records of all deliveries, data compiled, and appropriate statistical tests were applied.Results: The study included 209 women with mean gestational age of 38.76 ± 1.00 weeks and mean induction-delivery interval of 17.45 ± 8.70 hours (16.98 hours in group 1 versus 19.23 hours in group 2). Most (75%) women delivered vaginally. Only one of the neonates had an Apgar score of less than 7 at 5 min. Average neonatal ICU length of stay was 5.52 days (5.27 days in group 1 versus 6.17 days in group 2). Among all the maternal and neonatal outcomes studied, only the mean birth weights among the two groups was found to be statistically significant (p = 0.0017).Conclusions: Women with isolated oligohydramnios and their neonates were not found to suffer any additional harm due to labor induction at term than women who had oligohydramnios associated with other complications.

Is pregnancy associated plasma protein-A (PAPP-A) a marker for adverse perinatal outcomes in preterm isolated oligohydramnios cases?

OBJECTIVE

Isolated oligohydramnios is defined as an amniotic fluid index below five centimeter with no other coexisting condition. There are still controversies about the management and pregnancy outcomes. A marker predicting these is crucial. Low pregnancy associated plasma protein-A levels were reported to be related with adverse pregnancy outcomes. We aimed to determine the role of first trimester pregnancy associated plasma protein-A for poor outcomes in preterm isolated oligohydramnios cases.

MATERIAL AND METHODS

Fifty-one patients with singleton pregnancies diagnosed as isolated oligohydramnios at 28/0-36/6 weeks of gestation and 110 gestational age matched healthy controls between January and December 2015 were included. Maternal age, gestational age at delivery, mode of delivery, indication for cesarean section, Apgar scores at first and fifth minutes, birth weight, neonatal intensive care unit admission and mortality were recorded. Pregnancy associated plasma protein-A levels were compared between groups and its role in adverse perinatal outcomes was evaluated.

RESULTS

Pregnancy associated plasma protein-A levels and pregnancy outcomes were similar in two groups (p > 0.050) except birth weight, gestational age at delivery and presence of fetal distress. Pregnancy associated plasma protein-A levels did not differ in terms of delivery mode, presence of fetal distress, first and fifth minutes Apgar scores and neonatal intensive care unit admission (p = 0.323,0.650,0.990,0.112,0.853). Also, it was not determined as a risk factor for cesarean section, presence of fetal distress, low Apgar scores and neonatal intensive care unit admission.

CONCLUSION

Pregnancy associated plasma protein-A, a well-known prognostic factor for some of high risk pregnancy conditions, may not be used as a marker in preterm isolated oligohydramnios cases.