麻豆传媒

DALLAS -- Cervical pessary did not reduce the risk of spontaneous preterm birth in women with threatened preterm labor, researchers said here.

There was a non-significant difference in spontaneous preterm birth at <37 weeks gestation among women with threatened preterm labor in the pessary group versus controls with no pessary (48% vs 39%, RR 1.2, 95% CI 0.83-1.8), reported Frederik J. Hermans, MD, of Academic Medical Center in Amsterdam, and colleagues.

In fact, there was a trend towards a slight increase in preterm birth in the pessary group compared with controls for women <32 weeks gestation, he said in a at the Society for Maternal-Fetal Medicine's Annual Pregnancy Meeting.

Hermans said that around 10% of pregnancies are complicated by preterm birth, but delivery in less than 7 days after threatened labor only occurs in 10% of women, and the risk of preterm birth is around 50% in the subsequent weeks. This is the sixth APOSTEL study from this group, which has been attempting to discover mechanisms to prevent threatened preterm birth.

Neil Seligman, MD, of the University of Rochester Medical Center in New York, who was not involved with the research, said that pessaries have been studied for prevention of preterm birth in singleton and twin pregnancies in predominantly women without a history of preterm birth.

"The results of these studies have been largely conflicting which explains why pessary use hasn't gained much traction in the United States," he told 麻豆传媒.

Hermans' group examined pregnant women with a gestational age from 24 to around 35 weeks with a singleton or twin pregnancy. He noted that few twin pregnancies were included and the primary analysis was performed only on singleton pregnancies.

These women had signs and symptoms of preterm labor and a cervical length less than 15 mL, or had a cervical length between 15 and 30 mL and a positive fetal fibronectin test. All women had no delivery within 48 hours of admission.

Overall, 64 women were analyzed in the pessary group and 64 with no pessary. Women were a mean age 29-3, and there was a higher portion of non-Caucasian women in the pessary group (27% vs 13%). More than half of both groups were nulliparous and among multiparous women, about a quarter of both groups had a history of preterm birth. More than a third of each group had risk factors for preterm birth.

There was no significant difference in rates of preterm birth at <37 weeks, <34 weeks, or <32 weeks, and in every instance, a higher portion of the pessary group had preterm birth versus no pessary. There were also no differences in a composite of adverse perinatal outcomes, and there was a slightly higher, but non-significant, rate of NICU admission in the pessary group.

Side effects were more common in the pessary group, especially vaginal discharge. There was one severe complication -- a cervical rupture requiring surgery in the pessary group. The authors noted that an interim analysis of the data was halted because the chances the pessary would improve the primary outcome was futile, and "outside the trial, several other cases of cervical rupture had been reported in women with contractions."

One of the attendees at the presentation called the pessary "controversial," and Seligman said that would be a "fair assessment." But he added his hopes for future research to help prevent the problem of preterm birth.

"There is a dearth of effective interventions to prevent preterm birth; hopefully the authors will publish their results so we can determine whether the study design warrants additional research or we should investigate other interventions," he said.