A 32-year-old woman, gravida 2 para 1, at 28 weeks gestation comes to the office for a prenatal visit. The patient has had no contractions, vaginal bleeding, or leakage of fluid. Fetal movement has been normal. This pregnancy has been uncomplicated, but her last pregnancy ended with a low transverse cesarean delivery due to an abnormal fetal heart rate tracing. The patient has no chronic medical conditions and takes a daily prenatal vitamin. Vital signs are normal. Fetal heart rate is 145/min and fundal height is 24 cm. An ultrasound is performed due to a discrepancy between fundal height and gestational age, and shows a posterior placenta; a normal amniotic fluid volume; a fetus in transverse lie with shoulder presentation; and estimated fetal weight consistent with gestational age. The patient is concerned about the fetal presentation; she asks if the baby will stay in this presentation and if she can have a vaginal delivery. Which of the following is the most appropriate response to this patient?

Question

A 32-year-old woman, gravida 2 para 1, at 28 weeks gestation comes to the office for a prenatal visit.  The patient has had no contractions, vaginal bleeding, or leakage of fluid.  Fetal movement has been normal.  This pregnancy has been uncomplicated, but her last pregnancy ended with a low transverse cesarean delivery due to an abnormal fetal heart rate tracing.  The patient has no chronic medical conditions and takes a daily prenatal vitamin.  Vital signs are normal.  Fetal heart rate is 145/min and fundal height is 24 cm.  An ultrasound is performed due to a discrepancy between fundal height and gestational age, and shows a posterior placenta; a normal amniotic fluid volume; a fetus in transverse lie with shoulder presentation; and estimated fetal weight consistent with gestational age.  The patient is concerned about the fetal presentation; she asks if the baby will stay in this presentation and if she can have a vaginal delivery.  Which of the following is the most appropriate response to this patient?

Quizplus · Accepted Answer

11ec25c8_da77_6faa_bc81_7705b176277f_MD0003_00 This fetus has a transverse lie (ie, fetal spine is perpendicular to the long axis of the uterus) and shoulder presentation (shoulder is the fetal body part closest to the cervix). At an earlier gestational age, the fetus is mobile due to its small size when compared with the amniotic fluid volume and intrauterine cavity size. Therefore, abnormal fetal lie and malpresentation (eg, shoulder, breech) are common and frequently change. With increasing gestational age, increased fetal growth and relative decreased amniotic fluid volume lead to decreased fetal mobility. By term (ie, ≥37 weeks gestation), the majority of fetuses will have spontaneously rotated into a longitudinal lie (ie, fetal spine is parallel to the long axis of the uterus) and cephalic presentation as this prepares the fetus for delivery and is the most effective way to occupy the intrauterine cavity. Therefore, patients with transverse lie and malpresentation at preterm gestations are managed expectantly with an ultrasound at term to evaluate fetal presentation. (Choices A and B) Contraindications to a vaginal delivery include a placenta previa and prior classical (vertical incision) cesarean delivery. If this fetus rotates to cephalic presentation, the patient can undergo a trial of labor after a cesarean delivery as the risk of uterine rupture with a prior low transverse cesarean delivery is low and the placenta does not cover the cervix. (Choices D and E) External cephalic version (ECV), a procedure in which the fetus is manually rotated to cephalic presentation, can be performed in patients with malpresentation at ≥37 weeks gestation but not in preterm patients as most fetuses will spontaneously rotate. In addition, ECV has a risk of prelabor rupture of membranes and abruptio placentae, which require delivery (and possible prematurity complications if delivered at <37 weeks gestation). ECV is not recommended during active labor due to its low success rate at that time. External cephalic version Educational objective: Transverse lie, when the fetal spine is perpendicular to the long axis of the uterus, is common at early gestational ages. Most fetuses spontaneously convert to longitudinal lie and cephalic presentation by term (ie, ≥37 weeks gestation); therefore, preterm transverse lie is managed expectantly. References: Management of fetal malpresentation. (http://www.ncbi.nlm.nih.gov/pubmed/25811125) Practice bulletin no. 161: external cephalic version. (http://www.ncbi.nlm.nih.gov/pubmed/26942387)

A 32-Year-Old Woman, Gravida 2 Para 1, at 28 Weeks