DALLAS (FRONTLINE MEDICAL NEWS) – Placing a cerclage conferred additional benefit over vaginal progesterone alone for women with extreme short cervixes and singleton pregnancies, in a recent study. Those who received rescue cerclage in addition to vaginal progesterone had a 92% overall reduction in spontaneous preterm birth rates, and infants had fewer neonatal ICU admissions and neonatal complications.

There were also fewer perinatal and neonatal deaths when cerclage was placed, in the first study that directly compared vaginal progesterone alone with add-on cerclage for women with short cervixes and singleton pregnancies.

The single-center retrospective cohort study of 75 women with cervical length less than 10 cm who were receiving vaginal progesterone was presented by Christopher Enakpene, MD , at the meeting sponsored by the Society for Maternal-Fetal Medicine.

Women who received rescue cerclage in addition to progesterone delivered at a mean 34.3 weeks gestational age, compared with 27.5 weeks for those receiving progesterone alone (P less than .001).

There were 13 neonatal ICU admissions for infants born to the 36 patients in the cerclage group, compared with 23 for the 39 women receiving progesterone alone (P = .009). And there were seven perinatal or neonatal deaths among the group who did not receive cerclage; no deaths occurred in the cerclage group.

“Premature cervical ripening plays a significant role in spontaneous preterm birth,” said Dr. Enakpene. “And studies have shown that, the shorter the cervix, the higher the risk of spontaneous preterm birth.”

Preterm birth, said Dr. Enakpene, is the top cause of neonatal morbidity and mortality both in the United States and worldwide; it is associated with 70% of neonatal deaths and half of all neurodevelopmental delay, he said.

At the University of Illinois at Chicago, where Dr. Enakpene is a maternal-fetal medicine fellow in the department of obstetrics and gynecology, all pregnant women are screened for cervical length by transvaginal ultrasound during their second trimester.

If screening reveals cervical length of less than 20 mm, the patient receives vaginal progesterone, “the current standard of care in singleton pregnancy with incidental short cervix,” said Dr. Enakpene. Vaginal progesterone can reduce the risk of spontaneous preterm birth by about half, he said.

At his facility, women with a short cervix then receive serial cervical length assessments every week or 2 until 24 weeks’ gestation, to identify women whose cervixes continue to shorten. For these women, it’s usually physician preference that determines whether cerclage is placed to reinforce the progressively shortening cervix, said Dr. Enakpene.

There had been previous retrospective work showing that cerclage was more effective at preventing spontaneous preterm birth than was doing nothing when a woman with a singleton pregnancy had a short cervix. However, Dr. Enakpene said that vaginal progesterone alone had not been compared with continuing progesterone and adding a cerclage.

During the study period, 310 women with cervical length of less than 20 mm were placed on progesterone. These women were included in the study cohort if, over the course of at least two cervical length measurements, their cervix shortened to less than 10 mm while they were on vaginal progesterone. They could not have indications that delivery was imminent when the 10 mm threshold was met, said Dr. Enakpene.

Women with known intrauterine fetal death, an undesired pregnancy, or any sign of intra-amniotic infection or fetal anomalies were excluded from the study.

A total of 75 women met final inclusion criteria, and received cerclage (n = 36), or not (n = 39) according to physician judgment. Demographic and pregnancy-specific characteristics were generally similar between the two groups.

In their statistical analysis, Dr. Enakpene and his colleagues used Kaplan-Meier survival analysis to look at pregnancy latency over time for women who did – or didn’t – receive a cerclage. There were significantly fewer spontaneous preterm births before 24, 28, and 34 weeks gestational age in the cerclage group (P less than .001 for all).

Dr. Enakpene acknowledged the study’s limitations, including its retrospective nature, the small sample size, and the fact that cerclage placement was done by the preference of the attending physician. However, this study was the first to examine rescue cerclage as add-on to vaginal progesterone, he said, adding, “Following this study, we are designing a prospective randomized interventional study to address this important topic.”

Dr. Enakpene reported that he had no conflicts of interest, and reported no outside sources of funding.

SOURCE: Enakpene C et al. Am J Obstet Gynecol. 2018 Jan;218:S72-S73 .