Delivering an extremely low birthweight (ELBW) infant (
Delivering an extremely low birthweight (ELBW) infant (<600 g) when the mother has prolonged premature rupture of membranes can be a technical challenge. C/S is often chosen as the route of delivery because it is assumed to be less traumatic to the fetus than a trial of labor and planned vaginal delivery. When oligohydramnios is present, the uterine cavity can become distorted, making for difficulties in opening the uterus and safely extracting the fetus. Under such circumstances, traumatic injury is not unusual. Blood loss associated with extending the hysterotomy incision can result in maternal morbidity. The case here describes how we facilitate extraction of an ELBW fetus in the setting of oligohydramnios.
Case report A 26-year-old gravida 3, para 1011 presented to labor and delivery at 25 weeks' gestation with a severe headache. Her initial blood pressures were 173/103 and 161/100. Bedside ultrasound revealed severe oligohydramnios (AFI = 4 cm) and a breech fetus with an estimated fetal weight of 550 g. The patient was started on magnesium sulfate and antibiotics, and a course of steroids.
On the third hospital day, a 24-hour urine collection demonstrated a dramatic increase in proteinuria (5.54 g). We decided to deliver when recurrent variable fetal heart rate decelerations were noted later that day.
The neonate was a 460-g female who appeared to have had intrauterine growth restriction. Her Apgar scores were 6 and 7 at 1 and 5 minutes, respectively. The umbilical artery pH was 7.21 with a base deficit of –3.
In the neonatal intensive care unit, the infant was noted to be pink and making spontaneous respiratory efforts. She opened her eyes and had good movement of all four extremities. There was no evidence of trauma. A neonatal head scan taken on the second day of her life was normal. At age 6 months, no traumatic injury of any type had been identified.
Discussion Nitroglycerin-induced relaxation directly reverses fetal entrapment caused by excessive uterine tone and/or activity. Profound and brief relaxation of the myometrium allows for safer manipulation of the fetus. We use nitroglycerin at a dosage of 50 to 500 µg, depending upon the situation. We find that for obstetric applications, it is particularly useful to administer the drug in small (50- to 100-µg) aliquots.1-3 Because of the limited duration of uterine tone, risk of hemorrhage is minimal.4 The rapid onset (30 seconds) and brief duration of action (90 seconds) makes this approach ideal for obstetrical use.
From a clinical point of view, whether a difficult delivery can be anticipated or occurs spontaneously occurs, the approach we've described can benefit both the neonate and the mother. The technique results in less trauma during delivery, which is obviously one of the goals of C/S.
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fax (973-847-5340) or mail (5 Paragon Drive, Montvale, NJ 07645). All submissions are subject to peer review by the Contemporary OB/GYN Editorial Board. Nevertheless, the concepts discussed may be anecdotal in nature.
REFERENCES1. Greenspoon JS, Kovacic A. Breech extraction facilitated by glyceryl trinitrate sublingual spray. Lancet. 1991;338:124-125.
2. DeSimone CA, Norris MC, Leighton BL. Intravenous nitroglycerine aids manual extraction of retained placenta. Anesthesiology. 1990;73:787.
3. Altabef KM, Spencer JT, Zindberg S. Intravenous nitroglycerine for uterine relaxation of an inverted uterus. Am J Obstet Gynecol. 1992;166:1237-1238.
4. Mayer DC, Weeks SK. Antepartum uterine relaxation with nitroglycerine at cesarean delivery. Can J Anesth. 1992;39:166-169.