Clinical abdominal palpation for predicting oligohydramnios in suspected prolonged pregnancy

Abstract

Objective. In view of the scarcity of ultrasound in low-resource settings, to evaluate abdominal palpation for prediction of oligohydramnios in suspected prolonged pregnancy, using the ultrasound-obtained amniotic fluid index (AFI) as a gold standard, taking into account maternal and fetal factors that may affect amniotic fluid volume. 

Methods. A cross-sectional analytical study at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa, on women referred from midwife-run clinics with suspected gestational age ≥41 weeks. Eligible women had their AFI measured, then had abdominal palpation by the researcher, who was blinded to exact gestational age and AFI findings. Palpation focused on ballottability of fetal parts, ease of feeling fetal parts, and impression of fetal compaction. Gestational age was then recalculated using information from earlier ultrasound scans and menstrual dates. Univariable and multivariable logistic regression was performed with oligohydramnios (AFI <5 cm) as the dependent variable.

Results. Of 100 women, 45 had a recalculated gestational age ≥41 weeks. Twenty-three had oligohydramnios. Gestational age was a significant independent predictor for oligohydramnios (odds ratio (OR) 1.78; 95% confidence interval (CI) 1.08 - 2.94). The only component of palpation significantly associated with oligohydramnios, after adjustment for gestational age, was non-ballottability of the presenting part (adjusted OR 4.02; 95% CI 1.05 - 15.4). Non-ballottability had a sensitivity and specificity for oligohydramnios of 87% and 40%, respectively, with a negative predictive value of 91%.

Conclusion. When ultrasound is not available, ballottability of the presenting part may have value for excluding oligohydramnios and assisting clinical decisions in suspected prolonged pregnancy.