A 39-year-old woman, gravida 3 para 2, comes to the office at 20 weeks gestation for prenatal care and follow-up of a prenatal ultrasound. The patient has had no pelvic pain, leakage of fluid, or vaginal bleeding. Fetal movement has been normal. Prior pregnancies were uncomplicated and delivered vaginally at term. This pregnancy was conceived via in vitro fertilization with normal preimplantation genetic testing. Blood pressure is 110/60 mm Hg and pulse is 78/min. BMI is 32 kg/m². Ultrasound performed earlier today showed a single fetus in the breech presentation, a placenta covering the internal cervical os, and a cervical length of 4.2 cm. The anatomical survey is normal, and estimated fetal weight is at the 50th percentile. Based on the ultrasound findings, which of the following is the best next step in the treatment of this patient?

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11ec25c8_da15_ef09_bc81_9fad405404bf_MD0003_00 Placenta previa is usually diagnosed during routine prenatal ultrasound at 18-20 weeks gestation with placental tissue covering the cervix. Most patients are asymptomatic but have a significant risk of severe painless antepartum hemorrhage due to partial placental detachment with cervical manipulation or dilation. Pelvic rest and abstinence from intercourse (due to potential cervical contact) are recommended, and clinicians should refrain from digital cervical examination. Placenta previa The majority (~90%) of cases resolve spontaneously due to lower uterine segment lengthening and/or placental growth toward the fundus; therefore, initial management is with routine obstetric care. Repeat ultrasound is performed in the third trimester (ie, ≥28 weeks gestation), and patients with previa resolution can continue routine care without pelvic rest restrictions. Asymptomatic patients (ie, no vaginal bleeding) with persistent previa undergo scheduled cesarean delivery at 36-37 weeks gestation. (Choice A) Cerclage treats cervical insufficiency by reinforcing the cervix with suture or synthetic tape; candidates include patients with a history of second-trimester deliveries or a short (≤2.5 cm) cervix. It is not indicated in this patient with 2 prior term deliveries and a normal cervix, and it has no role in the management of placenta previa. (Choice B) Complete bedrest is associated with an increased risk of venous thromboembolism and loss of bone density. In addition, it has not been proven to be beneficial in obstetric management and therefore is not recommended. (Choices C and E) Progesterone supplementation reduces the risk of preterm birth in patients with prior preterm birth (by intramuscular hydroxyprogesterone) or those with an incidental short cervix (with vaginal progesterone). This patient's prior pregnancies were delivered at term, and her cervix is normal (>2.5 cm). (Choice F) Doppler ultrasound of the umbilical artery is performed during surveillance of fetal growth restriction (estimated fetal weight <10th percentile); this patient's fetal growth is normal (50th percentile). Educational objective: Placenta previa is diagnosed on prenatal ultrasound, when the placental tissue is seen covering the cervix. Cervical manipulation may cause severe painless antepartum hemorrhage; therefore, pelvic rest (ie, no digital cervical examination or intercourse) is recommended. Asymptomatic patients (ie, no vaginal bleeding) undergo routine obstetric care and third-trimester ultrasound to evaluate for previa resolution. References: Abnormal placentation: placenta previa, vasa previa, and placenta accreta. (http://www.ncbi.nlm.nih.gov/pubmed/26244528)

A 39-Year-Old Woman, Gravida 3 Para 2, Comes to the Office