Wednesday, February 17, 2016

OPPTIMUM Trial: vaginal progesterone does not help in preterm birth prevention !



Preterm birth is a global problem, with a prevalence of 8 to 12% depending on location.


Several large trials and systematic reviews have shown progestogens to be effective in preventing or delaying preterm birth in selected high risk women with a singleton pregnancy (including those with a short cervix or previous preterm birth).


However, the OPPTIMUM study results presented recently at the Society for Maternal and Fetal Medicine (SMFM) 36th Annual pregnancy meeting at Atlanta Georgia in February, 2016 have shown that vaginal progesterone confers no obstetrical or neonatal benefit, and no long-term benefit with respect to cognitive and neurosensory outcomes in children when used to prevent preterm birth.


The findings from OPPTIMUM – the largest trial to date looking at progesterone for the prevention of preterm birth – have important implications for current practice. Vaginal progesterone is not currently approved for the prevention of preterm birth in the United States, but is commonly used off label for this purpose.


The OPPTIMUM study is a randomized double blind placebo controlled trial recruited over 1,228 women around  UK to test whether giving natural progesterone daily from 22 to 34 weeks of gestation is a cost-effective way to reduce the likelihood of preterm birth.  It also aims to look whether compared to placebo, vaginal progesterone:

  • improve obstetric outcome by lengthening pregnancy and thus reducing the incidence of preterm delivery (before 34 weeks gestation)?
  • improve neonatal outcome by reducing a composite of death and major morbidity?
  • lead to improved childhood cognitive and neurosensory outcomes at two years?
  • represent cost effective management for women at high risk of preterm delivery?

Dr. Jane Norman, MD, from the University of Edinburgh in the United Kingdom said “We saw no significant effect of vaginal progesterone on obstetrical, neonatal, or childhood outcomes, this was true even for women with a cervix of 25 mm or less, and "we found no evidence of benefit in any identifiable subgroups."


A Cochrane meta-analysis  in 2013 assessed the role of both the vaginal and intramuscular form of progesterone in preventing PTB (Cochrane Database Syst Rev. 2013;7:CD004947). Progesterone was shown to prevent preterm births, reduce perinatal mortality, reduce the incidence of birthweight below 2500 g, and reduce neonatal deaths. In women with a short cervix, progesterone was shown to reduce preterm births, but did not affect the other parameters. 


But there has been little information about the long-term risk this may have on children Dr Norman explained. "We felt we needed to look at the long-term effects. We cannot assume that things with short-term benefit will not have long-term harm," she added.


The study recruited 1228 women with singleton pregnancies at risk for preterm birth because of a positive fetal fibronectin test, a history of spontaneous preterm birth at 34 weeks of gestation or earlier, or a cervical length 25 mm or less.



About 618 women were randomized to receive 200 mg of natural vaginal progesterone starting at 22-24 weeks and continuing to 34 weeks, compared with 600 women who received placebo.



The primary obstetric outcome was delivery <34 weeks of gestation, the primary neonatal outcome is a composite of death or two markers of neonatal morbidity (brain injury or bronchopulmonary dysplasia); and the primary childhood outcome is developmental status at two years. A formal economic evaluation was also a key part of the study.



It was seen that progesterone had no significant effect on either the obstetric or childhood outcomes. It also had no significant effect on any components of the primary outcome, including fetal death or live-born delivery before 34 weeks.


“A secondary analysis looking at the individual components of the composite neonatal outcomes showed that progesterone reduced the risk of brain injury and neonatal death, but not bronchopulmonary dysplasia.” Dr. Norman said.


“We were really surprised that we didn’t show that progesterone prevented preterm birth, and we became concerned that perhaps our cutoff of 34 weeks was just the wrong time to choose a cutoff,” Dr. Norman said, noting that a post hoc survival curve analysis was performed to look at the trajectory to delivery, and a “very marginal benefit” was seen with progesterone, but the difference was not statistically significant.


On subgroup analysis it was seen that in women with a short cervix, no evidence was seen that progesterone was more or less effective than in women with a longer cervix. Other subgroups studied included fibronectin-positive and fibronectin-negative women and women with a history of preterm birth. Progesterone was no more or less effective in any of these subgroups. 


“OPPTIMUM is the largest trial of progesterone to prevent preterm birth, and after adjusting for multiple comparisons as we planned, we did not disprove the null hypothesis that progesterone doesn’t prevent preterm birth, it doesn’t reduce adverse neonatal outcomes, and it doesn’t have a beneficial effect on childhood outcomes,” Dr. Norman said, concluding that “there is a remaining unmet need for a safe and effective agent to prevent preterm birth.”



Further it was commented at the  Society for Maternal and Fetal Medicine (SMFM) conference by Mary D'Alton, MD, the William C. Rappleye Professor of Obstetrics and Gynecology at the Columbia University Medical Center in New York Citythat that the results should not be extrapolated to 17-hydroxyprogesterone, which was not part of this analysis.



This certainly gives pause around vaginal progesterone," said Mary D'Alton, MD, the William C. Rappleye Professor of Obstetrics and Gynecology at the Columbia University Medical Center in New York City. But she said she would not advise a change in practice before seeing the final published results.


The US Food and Drug Administration has not approved vaginal progesterone for the prevention of preterm birth in women with a short cervix.

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