Background: Cephalopelvic disproportion is one of the most common indications for cesarean section. Abnormal labor patterns have been used to identify this condition for many years, but early diagnosis is sometimes quite difficult.
Objective: To determine the accuracy of the modified Mueller-Hillis maneuver in predicting successful vaginal delivery in the late active phase of the first stage of labor.

Materials and Methods: From July 1st 2009 to August 31st 2010, a diagnostic test was performed of pregnant women admitted to the Labor Room in Rajavithi Hospital who met the following inclusion criteria: singleton pregnancy; labor pain, vertex presentation, and gestational age between 37 and 42 weeks. The exclusion criteria were medical or obstetric complications, or induction of labor with uterotonic agent. The modified Mueller-Hillis maneuver was performed by a single operator applying fundal pressure and assessing the descent of the fetal head in the late active phase of the first stage of labor (cervical dilatation >8 cm). Descent of the fetal head of 1 cm or more was interpreted as a positive result, and successful vaginal delivery was defined as spontaneous vaginal delivery without instrumentation.

Results: Two hundred and twenty-six women were enrolled, 214 of whom had positive results, with 212 successful vaginal deliveries, one case of delivery by forceps extraction, and another of cesarean delivery. Of the 12 cases with negative results, 4 had successful vaginal delivery while the others were delivered by cesarean section. The sensitivity, specificity, accuracy, positive and negative predictive values of the positive test were 98.2%, 88.9%, 97.8%, 99.5%, and 66.7%, respectively.

Conclusion: The modified Mueller-Hillis technique performed in the late active phase of the first stage of labor yielded excellent results in terms of diagnostic parameters such as sensitivity, specificity, accuracy and positive predictive values, but the negative predictive values were only fair.

Keywords: Modified Mueller-Hillis maneuver, Vaginal delivery, First stage of labor