乌鸦传媒

Pregnant women with a shorter cervix did not experience a lower rate of preterm delivery with a cervical pessary (a device designed to help prevent the onset of labor) compared with those receiving normal care, a small randomized trial from the U.K. found.

In an intention-to-treat analysis, a slightly larger portion of women in the pessary group were associated with spontaneous preterm delivery (prior to 34 weeks gestation) than those who received "expectant management," or the usual prenatal care (12.0% versus 10.8%, respectively, P=0.57), reported , of King's College in London, and colleagues.

These results remained nonsignificant after adjusting for cervical length, participating center, obstetrical history, progesterone use, and antibiotic treatment (P=0.68). When examining the women who did not give birth prior to 34 weeks gestation, there was no difference between the pessary and the expectant management group (P=0.54), the authors wrote in

There was a slight wrinkle to this particular trial, in that while the participants were women with a short cervix (≤25 mm), participants from either group whose cervix was less than 15 mm at any point during the trial were given vaginal progesterone (a commonly used treatment to help prevent preterm labor).

But , of Mount Sinai Hospital in New York City, said that introducing this treatment may have had the potential to impact the study.

"Administration of vaginal progesterone occurred in close to half [45%] of the participants in both groups," Stone, who was not involved with the research, wrote in an email to 乌鸦传媒. "The use of progesterone may have ameliorated the possible benefits of pessary placement."

In fact, Stone added that the administration of vaginal progesterone was "a major difference" in this study compared with the other two randomized trials on the effect of the cervical pessary. Each had conflicting results: one found for the intervention and one saw

Nicolaides' team also cited , where participants with a cervical length of 15 mm or less were administered vaginal progesterone, and their rate of spontaneous preterm delivery was lower than those who did not receive that treatment.

This open-label, multicenter trial initially planned to randomize 1,600 patients with a singleton pregnancy between 20 and 24 weeks gestation. However, only 935 participants underwent randomization (465 to pessary and 467 to controls). Notably, nearly 30% of those patients had a cervix from 1 to 15 mm (compared with the expected 14%), which may have explained why the rate of spontaneous delivery was higher than the 6% rate expected by the authors.

In terms of secondary outcomes, most adverse events were infrequent, and the differences between the pessary and expectant management groups were nonsignificant:

• Rates of perinatal death (3.2% versus 2.4%, respectively, P=0.42)
• Adverse neonatal outcomes (6.7% versus 5.7%, respectively, P=0.55)
• Neonatal special care (11.6% versus 12.9%, respectively, P=0.59)

At follow-up, however, there was a significant difference in the amount of new or increased maternal vaginal discharge (46.8% in the pessary group versus 13.8% in those receiving expectant management, P<0.001) as well as pelvic discomfort (11.4% versus 3.4%, respectively, P<0.001). The authors note that the pessary group initially reported a significant difference in vaginal discharge compared with the controls (P=0.02) but not pelvic discomfort (P=0.14).

There were seven neonatal deaths in the pessary group (1.5%) and five in the control group (1.1%). There were no cases of maternal death, serious vaginal trauma due to insertion or removal of the pessary, or reported chorioamnionitis.

In addition, 114 (24.5%) of participants in the pessary group had the device removed prior to 34 weeks gestation. The most common reason was patient request (47 participants; 25 of those due to discomfort), followed by preterm labor or pre-labor rupture of membranes (40), and preterm labor (20).

The limitations to the study include the fact that only 58% of the planned 1,600 participants underwent randomization, although that number is still larger than in the two previous trials. In addition, the larger portion of women with a cervical length ≤15 mm could have impacted the results, and the open label nature of the trial may have had an impact on medical decision-making.