Progestogens to prevent preterm birth in twin pregnancies: an individual participant data meta-analysis of randomized trials

<p>Abstract</p> <p>Background</p> <p>Preterm birth is the principal factor contributing to adverse outcomes in multiple pregnancies. Randomized controlled trials of progestogens to prevent preterm birth in twin pregnancies have shown no clear benefits. However, individual studies have not had sufficient power to evaluate potential benefits in women at particular high risk of early delivery (for example, women with a previous preterm birth or short cervix) or to determine adverse effects for rare outcomes such as intrauterine death.</p> <p>Methods/design</p> <p>We propose an individual participant data meta-analysis of high quality randomized, double-blind, placebo-controlled trials of progestogen treatment in women with a twin pregnancy. The primary outcome will be adverse perinatal outcome (a composite measure of perinatal mortality and significant neonatal morbidity). Missing data will be imputed within each original study, before data of the individual studies are pooled. The effects of 17-hydroxyprogesterone caproate or vaginal progesterone treatment in women with twin pregnancies will be estimated by means of a random effects log-binomial model. Analyses will be adjusted for variables used in stratified randomization as appropriate. Pre-specified subgroup analysis will be performed to explore the effect of progestogen treatment in high-risk groups.</p> <p>Discussion</p> <p>Combining individual patient data from different randomized trials has potential to provide valuable, clinically useful information regarding the benefits and potential harms of progestogens in women with twin pregnancy overall and in relevant subgroups.</p

Expression of Stretch-Activated Two-Pore Potassium Channels in Human Myometrium in Pregnancy and Labor

Background: We tested the hypothesis that the stretch-activated, four-transmembrane domain, two pore potassium channels (K2P), TREK-1 and TRAAK are gestationally-regulated in human myometrium and contribute to uterine relaxation during pregnancy until labor. Methodology: We determined the gene and protein expression of K2P channels in non-pregnant, pregnant term and preterm laboring myometrium. We employed both molecular biological and functional studies of K2P channels in myometrial samples taken from women undergoing cesarean delivery of a fetus. Principal Findings: TREK-1, but not TREK-2, channels are expressed in human myometrium and significantly up-regulated during pregnancy. Down-regulation of TREK-1 message was seen by Q-PCR in laboring tissues consistent with a role for TREK-1 in maintaining uterine quiescence prior to labor. The TRAAK channel was unregulated in the same women. Blockade of stretch-activated channels with a channel non-specific tarantula toxin (GsMTx-4) or the more specific TREK-1 antagonist L-methionine ethyl ester altered contractile frequency in a dose-dependent manner in pregnant myometrium. Arachidonic acid treatment lowered contractile tension an effect blocked by fluphenazine. Functional studies are consistent with a role for TREK-1 in uterine quiescence. Conclusions: We provide evidence supporting a role for TREK-1 in contributing to uterine quiescence during gestation an

17-Hydroxyprogesterone caproate to prolong pregnancy after preterm rupture of the membranes: early termination of a double-blind, randomized clinical trial

<p>Abstract</p> <p>Background</p> <p>Progestational agents may reduce the risk of preterm birth in women with various risk factors. We sought to test the hypothesis that a weekly dose of 17-hydroxyprogesterone caproate (17P) given to women with preterm rupture of the membranes (PROM) will prolong pregnancy and thereby reduce neonatal morbidity.</p> <p>Methods</p> <p>Double-blind, placebo-controlled randomized clinical trial. Women with PROM at 23.0 to 31.9 weeks of gestation were randomly assigned to receive a weekly intramuscular injection of 17P (250 mg in 1 mL castor oil) or placebo (1 mL castor oil). The primary outcome was the rate of continuing the pregnancy until 34.0 weeks of gestation or until documentation of fetal lung maturity at 32.0 to 33.9 weeks of gestation. Planned secondary outcomes were duration of latency period and rate of composite neonatal morbidity. Enrollment of 111 participants per group, 222 total, was planned to yield 80% power to detect an increase in the primary outcome from 30% with placebo to 50% with 17P.</p> <p>Results</p> <p>Twelve women were enrolled of whom 4 were randomly assigned to receive 17P and 8 to receive placebo. The trial was terminated prematurely because of two separate issues related to the supply of 17P. No adverse events attributable to 17P were identified.</p> <p>Conclusion</p> <p>Because of premature termination, the trial does not have adequate statistical power to evaluate efficacy or safety of 17P in women with PROM. Nonetheless, ethical principles dictate that we report the results, which may contribute to possible future metaanalyses and systematic reviews.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01119963">NCT01119963</a></p> <p>Supported by a research grant from the Center for Research, Education, and Quality, Pediatrix Medical Group, Sunrise, FL</p