Oligohydramnios at Term: A Case Report

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J. L. is a healthy, 20-year-old gravida 2 para 0010 at 41 and 0/7 weeks'gestation, based on the first day of her last menstrual period and first trimester ultrasound. She was admitted to the labor and delivery unit at 10:00 am for induction of labor. Earlier in the day, J. L. had a biophysical profile (BPP) performed per hospital protocol for all women whose pregnancies continued beyond 40 weeks'gestation. The BPP revealed an amniotic fluid index of 4.97 cm. All other components of the BPP were normal (fetal breathing, fetal tone, fetal movement, and reactive non-stress test). The estimated weight of the fetus was 3178 grams. J. L.'s prenatal course was uncomplicated. She had adequate fetal growth and no signs of maternal or fetal morbidity. Her initial cervical exam was 2 cm dilated, soft, posterior, 50% effaced, −2 station, and vertex. She was not having any uterine contractions. The amniotic membranes were intact. The baseline fetal heart rate (FHR) was 140 to 150 beats per minute (bpm) with moderate variability, accelerations, and no decelerations. The collaborating obstetrician recommended inducing labor with oxytocin infusion if labor did not begin spontaneously within 12 hours after admission. After 12 hours of observation, her vaginal exam was unchanged. The FHR pattern was reassuring throughout the day. At this time, after obtaining the patient's informed consent, the midwife began induction of labor per protocol, starting at 1 milliunits (mU) per minute of oxytocin, increasing 1 mU/minute every 20 minutes until a contraction pattern of every 2 minutes with moderate intensity was established. Three hours later, at an infusion rate of 6 mU/min, uterine contractions were every 3 to 4 minutes. At that time, an episode of prolonged fetal bradycardia occurred (to 70 bpm, lasting 90 seconds before returning to a baseline of 140–150 bpm). The oxytocin infusion was stopped, and an amniotomy was done. This revealed a small amount of clear, odorless fluid. A fetal scalp electrode was inserted. Nineteen hours after admission, 7 hours after beginning the labor induction, J. L. requested pain medication. One milligram of butorphanol tartrate augmented with 25 mg of promethazine was administered via intravenous (IV) push for pain relief. The oxytocin infusion was restarted at 1 mU/min, increasing by 1 mU every 20 minutes. Twenty-four hours after admission, an epidural was placed at J. L.'s request. At this time, her cervix was 5 cm, 80%, and −1 station. The FHR was reassuring and contractions were every 2 to 4 minutes. At 3:00 pm, 29 hours after admission, the consulting physician and midwife decided to do an amnioinfusion and place an intrauterine pressure catheter (IUPC) secondary to the presence of repetitive variable decelerations that had a quick recovery to baseline. At the time of the amnioinfusion and IUPC placement, J. L.'s vaginal exam was 8 cm, 100% effaced, and −1 station. The patient reported exhaustion and felt that she could not continue with the labor. Seven hours later, J. L. was contracting irregularly and reported that she had the urge to push but felt too exhausted; her cervix was anterior lip (9 cm), 100%, +1 fetal station. Thirty-five hours after being admitted to the labor unit, maternal pushing efforts began, the anterior lip was reduced, and the fetus's station was +2 with a well-flexed head. The FHR pattern was reassuring. After 1 hour and 50 minutes of maternal pushing effort, a decision was made by the patient, midwife, and physician to proceed with a cesarean section because of the arrest of fetal descent and maternal reports of exhaustion and inability to continue pushing. A vigorous baby boy was born at 11:45 pm, weighing 3265 grams, with Apagar scores of 9 and 9, at 1 and 5 minutes. Both mother and baby did well postpartum.