NEW YORK (Reuters Health) – Women with a singleton pregnancy and a prior preterm birth can be safely monitored with transvaginal ultrasound cervical length screening as opposed to routine history-indicated cerclage, a meta-analytic review of randomized trials indicates.
Cerclage can be reserved for the minority of women who develop a short cervix, conclude Dr. Vincenzo Berghella and Dr. A. Dhanya Mackeen of Jefferson Medical College of Thomas Jefferson University in Philadelphia.
“The message,” Dr. Berghella noted in an e-mail to Reuters Health, “is that women with prior preterm birth do not always have to have a cerclage at 12 to 14 weeks, but can instead be followed with cervical length, with those with a short cervix benefiting from cerclage.”
Cerclage, a stitch placed in the uterine cervix, is typically offered to women who have a history of one or more preterm births, but “the evidence for its efficacy as compared with no cerclage is limited,” the authors say.
They searched the relevant literature on this topic. They identified and included in their analysis four randomized trials involving a total of 467 asymptomatic pregnant women with a prior history of preterm birth.
Before 24 weeks gestation, the women were randomized to management with either second trimester transvaginal ultrasonographic cervical length screening and cerclage if the cervical length was found to be short or to cerclage based on history alone (i.e., previous preterm birth or second-trimester loss).
According to the investigators, the incidence of preterm birth before 37 weeks was similar in the screening group and the history-indicated cerclage group (31% and 32%, respectively). The incidence of preterm birth before 34 weeks was also similar (17% and 23%), as was the incidence of perinatal mortality (5% and 3%).
It’s noteworthy, the investigators say, that 58% of women monitored with a policy of transvaginal ultrasound screening never developed a short cervix and therefore avoided cerclage altogether.
Although the investigators did not do a formal cost-effectiveness analysis, they estimate that a policy of cervical length screening and cerclage in women who develop a short cervix (as opposed to history-indicated cerclage) would save a considerable amount of money and yield “seemingly similar outcomes.”
“A history-indicated cerclage placed for poor obstetric history,” the authors conclude, “may be reserved for women with three prior preterm births or second-trimester losses, whereas most singleton gestations in women with prior preterm birth can be monitored with transvaginal ultrasound cervical length screening and cerclage reserved for the minority who develops a short cervical length.”
Obstet Gynecol 2011.