A 39-year-old woman, gravida 2 para 1, at 28 weeks gestation comes to the hospital due to painful uterine contractions for the past 4 hours accompanied by the passage of clear fluid from her vagina. She initiated prenatal care a week ago, during which an anatomy ultrasound revealed a fetus with anencephaly. Her prior pregnancy was uncomplicated. She has no chronic medical conditions and has had no surgeries. The patient does not use tobacco, alcohol, or illicit drugs. Temperature is 37.2 C (99 F), blood pressure is 110/70 mm Hg, and pulse is 80/min. A sterile speculum examination reveals pooling of nitrazine-positive fluid in the vagina. The cervix is 4 cm dilated and 80% effaced. Bedside ultrasound reveals anhydramnios and an anencephalic fetus in breech presentation. Fetal heart rate is normal. Tocometer shows contractions every 3 minutes. Which of the following is the best next step in management of this patient?
Delivery planning for a nonviable fetus | |
Fetal diagnosis |
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Obstetric management |
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Neonatal management |
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Anencephaly is a lethal fetal anomaly characterized by the failure of neural tube closure, which results in the absence of the cerebrum, thalamus, hypothalamus, and portions of the brainstem. Affected infants typically die within hours of birth. The principle behind labor management of patients with lethal fetal anomalies (eg, anencephaly, bilateral renal agenesis) is to minimize maternal morbidity and mortality. Therefore, obstetric care for these patients is maternally focused. Vaginal delivery has a lower risk for maternal complications compared to cesarean delivery (eg, hemorrhage, infection, pulmonary embolism); therefore, it is the delivery modality of choice.
This patient, at 28 weeks gestation, is in labor after spontaneous rupture of membranes with a nonviable (anencephalic) fetus in breech presentation. Therefore, the best option for this patient is expectant management of her labor in anticipation of a spontaneous vaginal delivery. Fetal heart rate (FHR) monitoring is not indicated because it does not affect delivery management.
(Choices A and B) Antenatal corticosteroids decrease prematurity-related neonatal morbidity and mortality when administered to women at risk for delivery at <37 weeks gestation. Magnesium sulfate decreases the risk of cerebral palsy in infants of mothers at risk for delivery at <32 weeks gestation. Because this fetus's anomaly is lethal, neither antenatal corticosteroids nor magnesium sulfate is indicated.
(Choice D) Amnioinfusion is not indicated for anhydramnios (no amniotic fluid). Amnioinfusion is indicated for persistent variable decelerations; however, FHR monitoring is not performed in cases of lethal anomalies because the FHR does not affect delivery management. Tocolysis is indicated for preterm labor when prolongation of pregnancy can improve neonatal outcomes, but it would not be beneficial for this patient.
(Choice E) A breech presentation is typically an indication for cesarean delivery because it decreases the risk of fetal trauma and asphyxia associated with vaginal delivery (eg, head entrapment). However, in fetuses with lethal anomalies in which entrapment does not affect fetal outcome, vaginal delivery is preferred due to the increased risk of maternal complications associated with cesarean delivery.
Educational objective:
The priority for patients with lethal fetal anomalies such as anencephaly is to minimize maternal morbidity and mortality. Obstetric care is maternally focused, and typical management of preterm labor for neonatal benefit is not indicated.