A 24-year-old woman, gravida 2 para 1, at 20 weeks gestation, comes to the office for a routine fetal anatomy ultrasound. The patient feels well and has had no contractions, vaginal bleeding, or leakage of fluid. Fetal movement is normal. Her prior pregnancy was uncomplicated and ended in a vaginal delivery at 41 weeks gestation after labor induction for a postterm pregnancy. She has no chronic medical conditions, and her only medication is a daily prenatal vitamin. The patient does not use tobacco, alcohol, or illicit drugs. Temperature is 36.7 C (98 F), blood pressure is 110/80 mm Hg, and pulse is 72/min. The uterine fundus is at the umbilicus and is nontender. Ultrasound reveals a singleton fetus in breech presentation with a heart rate of 148/min. The lower edge of the placenta is 3 cm from the internal cervical os, and cervical length is 1.8 cm (normal: 2.5). Amniotic fluid index is 18 cm. Which of the following is the best next step in management of this patient?

Question

A 24-year-old woman, gravida 2 para 1, at 20 weeks gestation, comes to the office for a routine fetal anatomy ultrasound.  The patient feels well and has had no contractions, vaginal bleeding, or leakage of fluid.  Fetal movement is normal.  Her prior pregnancy was uncomplicated and ended in a vaginal delivery at 41 weeks gestation after labor induction for a postterm pregnancy.  She has no chronic medical conditions, and her only medication is a daily prenatal vitamin.  The patient does not use tobacco, alcohol, or illicit drugs.  Temperature is 36.7 C (98 F), blood pressure is 110/80 mm Hg, and pulse is 72/min.  The uterine fundus is at the umbilicus and is nontender.  Ultrasound reveals a singleton fetus in breech presentation with a heart rate of 148/min.  The lower edge of the placenta is 3 cm from the internal cervical os, and cervical length is 1.8 cm (normal: >2.5).  Amniotic fluid index is 18 cm.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_da7b_b56f_bc81_61559a247c0d_MD0003_00 Preterm delivery (ie, delivery at <37 weeks gestation) is common and is associated with significant neonatal morbidity and mortality. However, early identification of at-risk patients can decrease the incidence of preterm delivery and potentially reduce neonatal complications. In patients with no history of preterm delivery, risk assessment is typically with a cervical length measurement on transvaginal ultrasonography at 16-24 weeks gestation (Choice B). Most patients have a normal cervical length (ie, >2.5 cm) and can continue routine prenatal care. In contrast, those with an incidental short cervix (ie, cervical length ≤2.5 cm on ultrasound), such as this patient, are at increased risk for preterm delivery. The higher risk of preterm delivery is likely due to the inability of a shortened cervix to tolerate normal intermittent contractions with increasing gestational age, thereby allowing for preterm cervical dilation and effacement. Therefore, patients with an incidental short cervix are offered vaginal progesterone, which decreases prostaglandin production and maintains uterine relaxation throughout pregnancy, thereby decreasing the risk of preterm labor. (Choice A) A cerclage is indicated in patients with cervical insufficiency (ie, prior painless, second-trimester losses). However, it is not routinely recommended for patients with an incidental short cervix and no history of preterm delivery because the procedural risks (eg, accidental rupture of membranes, cervical injury) outweigh the potential benefits. cerclage (Choice C) Cervicovaginal fetal fibronectin (fFN) is a protein secreted during labor that can distinguish between preterm and false labor in patients with preterm contractions. However, fFN testing has high rates of false positives in patients who are asymptomatic or those at <22 weeks gestation; therefore, it cannot predict or prevent preterm labor in this patient. (Choice D) Bed rest does not decrease the rate of preterm delivery, but it does increase maternal risk of venous thromboembolism and bone loss. (Choice E) Terbutaline is a short-acting tocolytic agent used to inhibit uterine contractions (eg, treatment of uterine tachysystole). It is not used to manage an incidental short cervix. Educational objective: Pregnant patients with an incidental short cervix on ultrasound (cervical length ≤2.5 cm) are at increased risk for preterm delivery. Patients with an incidental short cervix and no history of preterm delivery are offered vaginal progesterone, which maintains uterine relaxation and decreases the risk of preterm labor. References: Vaginal progesterone decreases preterm birth =34 weeks of gestation in women with a singleton pregnancy and a short cervix: an updated meta-analysis including data from the OPPTIMUM study. (http://www.ncbi.nlm.nih.gov/pubmed/27444208) Vaginal progesterone prophylaxis for preterm birth (the OPPTIMUM study): a multicentre, randomised, double-blind trial. (http://www.ncbi.nlm.nih.gov/pubmed/26921136)

A 24-Year-Old Woman, Gravida 2 Para 1, at 20 Weeks