Antenatal Idiopathic Polyhydramnios: Then what?
Authors: Al Ibrahim Abdullah A , Aqel Ibrahim , Al Obaidly Sawsan , Khenyab Najat , Al Jenahi Najah , Al Mansori Zeena , El Bolushi Mariam 
Published: July 2019

Objective

To study the prevalence of neonatal complications among pregnancies complicated by polyhydramnios of unidentified prenatal cause and their outcome in an attempt to introduce more active antenatal/postnatal evaluation and aid the counseling.

Methods

A retrospective descriptive study to identify all the cases of idiopathic polyhydramnios for whom there was causes between 2002 and June 2014. All the cases of polyhydramnios during the study period were reviewed and only those with no obvious antenatal cause were included in the study. Only cases where polyhydramnios diagnosed using Deepest Vertical Pocket were included. The exclusion criteria are; diabetic pregnant patients, fetus who were diagnosed antenataly with congenital/genetic anomalies, Polyhydramnios diagnosed using Amniotic Fluid Index and those with incomplete data. We look for the rate of preterm delivery, IUFD, rate of cesarean section, low APGAR score admission to NICU and neonatal complications. We also use this study as an audit to identify those cases for which a genetic/congenital anomaly identified; making a proper antenatal work up as a crucial step in dealing with such cases. The collected data were put into Excel sheet (Microsoft Office 2013) and professional statistical tools were used (provided by StatPages.org), P value of 0.05 was taken as the limit for statistical significance.

Results

Total of 66 case of idiopathic polyhydramnios identified in the period from 2002 to med-2014, which account for about 0.4 in 1000 (total number of deliveries during this period was around 180000 deliveries). There were 58 cases (87.9%) with mild polyhydramnios (defined as deepest pocket of 8 to 11 cm, and 8 (12.1%) cases of moderate polyhydramnios (from 11.1 to 15 cm) the mean of amniotic fluid Deepest Pocket was 9.6 cm (SD 1.%). Maternal age was variable among the cases [range from 20 to 52 years (median of 30 years, and mean of 30.2 years (SD 5.7)], and those above 35 years [8 cases (12%)] all of them are mild polyhydramnios, so the degree of hydramnios does not direcetly correlate with advanced maternal age. 39 cases were diagnosed before 37 weeks (59.1%), of them 32 cases had mild Idiopathic Polyhydramnios ranging from 8–11 cm with no direct correlation of increasing Mild amniotic fluid DP and decreasing gestational age as the relation was variable. 5 patients who were diagnosed before 37 weeks were of Moderate Idiopathic Polyhydramnios, although the number is small but it seems Moderate IP is more prone to be present at early GA, however comparing both groups; there was no statistical significance [p value 0.17] Over all, the rate of preterm delivery was 10.6% (7 cases), 4 cases among mild IP (6.7%) and 3 cases among moderate IP (37.5%). As in the graphs the GA at delivery decreases as the deepest pool increases and that most prominent in moderate IP, less relevant in mild form. 22 cases had a cesarean sections (33%) which relatively high compared to the overall cesarean section rate of 25%. 8 of them where as an emergency setting; 4 were in Labour and taken for failed progress, 2 for fetal distress and 2 were previous cesarean came in labor and requested repeated cesarean. The remaining 14 cesarean were due to placenta previa (2 cases), repeated cesarean sections (7 cases), big baby (3 cases), transverse lie (1 case) and previous 2 shoulder dystocia (1 case). The rate of emergency cesarean section among mild IP was 8.8% (5 cases) compared to 12.5% (1 case) in the Moderate IP group, however there is no statistical significant difference between the 2 groups [p value of 0.73]. Overall rate of spontaneous labor noticed in 37 cases (56.1 %) Induction of Labour was significantly high (13 cases; 19.7%), mainly due to polyhydramnios (11 cases; 16.7%), only 2 cases due to High BP. Worth noticing that despite the high rate of Induction, however the rate of cesarean among induced patient was low (only 2 case; 15.4%) comparable to those who came in spontaneous labour (4 cases out of 37 patients; 10.8%). There is no statistical significant difference between the 2 groups [p value of 0.66] The rate of operative delivery was 7.7% (5 cases). All of them among those who came into spontaneous labor. On the other hand the operative delivery was noticed in 4 cases (7%) of mild IP compared to 1 case in moderate IP (12.5%), but no statistical significant difference between the 2 groups [p value of 0.59]. Over all Mean birth weight was 3503.4 grams (SD 645.4). Among the Mild IP group the mean birth weight was 3185.7 grams (SD 898.9), compared to the Moderate IP group whch was 3185.7 grams (SD 898.9); there was no statistical significant difference between the 2 groups [p value of 0.36]; however the rate of big babies (>4000 grams) was high among Mild IP (15 cases; 25.9%), the mean birth weight in such subgroup was 4175 grams (SD 229.5), there were no big babies among the moderate IP. Low birth weight ( = < 2500 grams) found in 6 cases (10.4%) of Mild IP (mean of 2166.6 (SD 367)) and 1 case (12.5%) of Moderate IP (1300 grams), there was no statistical significant difference between the 2 groups [p value of 0.85]. Low APGAR score (0–3 in the 1st 5 minutes) was found in 1 case of Mild IP (1.7%) and 1 case of moderate IP (12.5%), with no statistical significant difference between the 2 groups [p value of 0.096]. overall low APGAR score was 3%. MICU admission was 22.7 % (15 cases). 2 cases ended in neonatal death (3%), the degree of polyhydramnios did not increase NND the as in each group there is one case.Conclusion; Idiopathic polyhydramnios is an important pregnancy complication. It warrant detailed antenatal assessment, including ultrasound and repeated GTT. It also urges the postnatal examination of the baby for undiscovered pathology. We recommend taking care of such pregnancies in tertiary care center.