DALLAS – Though cervical pessaries didn’t significantly reduce the rate of births before 34 weeks’ gestation when compared to vaginal progesterone for women with short cervixes and twin pregnancies, neonatal outcomes were improved with pessary use, according to the first randomized controlled trial that directly compared the two therapies.
Of 148 women who received pessaries, 24 (16.2%) delivered before 34 weeks’ gestation, compared with 33 of 149 women (22.1%) who received vaginal progesterone (relative risk 0.73, 95% confidence interval, 0.46-1.18; P = .24). Women who received pessaries were slightly more likely to carry their twin gestations to at least 37 weeks (79/148 versus 91/149; P = .05).
Certain perinatal outcomes were also better among the pessary group. The study measured a composite poor perinatal outcome of neonatal intensive care unit (NICU) admission, intraventricular hemorrhage, respiratory distress syndrome, necrotizing enterocolitis, and neonatal sepsis. This composite poor outcome occurred in 18.6% of the pessary group, compared with 26.5% of the progesterone group (P = .02). Neonatal admissions were more common in the progesterone than in the pessary group (22.1% vs. 13.2%, P = .01)
The odds of having a baby with birth weight less than 2,500 g was also higher for those receiving progesterone, with 22.1% of the progesterone group and 13.2% of the pessary group delivering infants in this range (P less than .001).
Previous work has shown that vaginal progesterone was efficacious when compared with placebo in preventing preterm births for women who have a twin gestation and a short cervix, according to Vinh Dang, MD, the study’s first author. Similarly, he said, studies have shown that placement of a cervical pessary also reduces preterm births in the scenario of twin gestation and a short cervix.
“No randomized controlled trial has directly compared cervical pessary versus vaginal progesterone for the prevention of preterm birth” in this population, Dr. Dang said during a presentation at the Pregnancy Meeting, sponsored by the Society for Maternal-Fetal Medicine.
Accordingly, he and his colleagues at My Duc Hospital in Ho Chi Minh City, Vietnam, conducted a comparative effectiveness trial to provide a head-to-head comparison of the use of cervical pessaries versus vaginal progesterone for women with twin gestations and short cervixes.
The investigators conducted a single-center, randomized controlled trial, enrolling women with either monochorionic or dichorionic twin pregnancies at between 16 and 22 weeks of gestation, with a cervix length of less than 38 mm, as assessed by two trained ultrasonographers.
At My Duc Hospital, 28.4% of women with twin pregnancies and cervical length less than 38 mm delivered earlier than 34 weeks. This meant that in order to detect a 14% reduction in preterm birth, the study would need to include 290 women for sufficient statistical power, Dr. Dang said.
Patients (n = 300) were randomized 1:1 to receive vaginal progesterone, begun on the day of enrollment, or cervical pessary placed within 1 week of study enrollment. Two patients in the pessary arm and one in the progesterone arm were lost to follow-up.
Patients were permitted to receive other therapies; 14 women in the pessary arm also received antibiotics and 1 received progesterone. In the progesterone group, 12 received antibiotics, and 4 patients were cotreated with cervical cerclage.
The study excluded women under 18 years of age, and those with a prior history of cervical surgery or cervical cerclage. Major known complications in the current pregnancy, such as twin-to-twin transfusion syndrome, major congenital anomaly, fetal demise, and any symptoms of labor or late miscarriage were also grounds for exclusion.
Patient characteristics were similar between groups. The average age was 32 years. Most of the patients (83%-90%) were nulliparous, and more than 90% of the pregnancies were the result of assisted reproduction.
In addition to the primary outcome measure of preterm birth earlier than 34 weeks, the investigators tracked a number of obstetric and neonatal outcomes as secondary endpoints.
For the obstetric measures, Dr. Dang and his colleagues recorded deliveries that occurred before 28, 32, and 27 weeks’ gestation, whether labor was induced and if tocolytics or corticosteroids were used, mode of delivery, and proportion of live births. The number of days of admission for preterm labor, presence of chorioamnionitis, and occurrence of other maternal morbidity were also measured.
Dr. Dang and his colleagues also tracked birth weight, congenital anomalies, and 1- and 5-minute Apgar scores.
A prespecified subgroup analysis of women with even shorter cervixes – less than 28 mm – showed a significant reduction in preterm birth before 34 weeks in addition to the significant improvement in neonatal outcomes.
One author reported being a consultant for ObsEva, Merck, and Guerbet. The other authors had no disclosures.
SOURCE: Dang V et al. The Pregnancy Meeting Abstract LB03