Does Progesterone Treatment Influence Risk Factors for Recurrent Preterm Delivery?

Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy

BACKGROUND

Multiple pregnancy is a strong risk factor for preterm birth, and more than 50% of women with a twin pregnancy will give birth prior to 37 weeks' gestation. Infants born preterm are recognised to be at increased risk of many adverse health outcomes, contributing to more than half of overall perinatal mortality. Progesterone is produced naturally in the body and has a role in maintaining pregnancy, although it is not clear whether administering progestogens to women with multiple pregnancy at high risk of early birth is effective and safe. Since publication of this new review in Issue 10, 2017, we have now moved one study (El-Refaie 2016) from included to studies awaiting classification, pending clarification about the study data.

OBJECTIVES

To assess the benefits and harms of progesterone administration for the prevention of preterm birth in women with a multiple pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the administration of a progestogen by any route for the prevention of preterm birth in women with multiple pregnancy. We did not include quasi-randomised or cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports identified by the search for eligibility, extracted data, assessed risk of bias and graded the quality of the evidence.

MAIN RESULTS

We included 16 trials, which all compared either vaginal or intramuscular (IM) progesterone with a placebo or no treatment, and involved a total of 4548 women. The risk of bias for the majority of included studies was low, with the exception of three studies that had inadequate blinding, or significant loss to follow-up or both, or were not reported well enough for us to make a judgement. We graded the evidence low to high quality, with downgrading for statistical heterogeneity, design limitations in some of the studies contributing data, and imprecision of the effect estimate. 1 IM progesterone versus no treatment or placebo More women delivered at less than 34 weeks' gestation in the IM progesterone group compared with placebo (risk ratio (RR) 1.54, 95% confidence interval (CI) 1.06 to 2.26; women = 399; studies = 2; low-quality evidence). Although the incidence of perinatal death in the progesterone group was higher, there was considerable uncertainty around the effect estimate and high heterogeneity between studies (average RR 1.45, 95% CI 0.60 to 3.51; infants = 3089; studies = 6; I² = 71%; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (RR 1.05, 95% CI 0.98 to 1.13; women = 2010; studies = 5; high-quality evidence); preterm birth less than 28 weeks (RR 1.08, 95% CI 0.75 to 1.55; women = 1920; studies = 5; moderate-quality evidence); infant birthweight less than 2500 g (RR 0.99, 95% CI 0.90 to 1.08; infants = 4071; studies = 5; I² = 76%, moderate-quality evidence)). No childhood outcomes were reported in the trials. 2 Vaginal progesterone versus no treatment or placebo by dose There were no clear group differences in incidence of preterm birth before 34 weeks (average RR 0.90, 95% CI 0.66 to 1.23; women = 1503; studies = 5; I² = 36%; low-quality evidence). Although fewer births before 34 weeks appeared to occur in the progesterone group, the CIs crossed the line of no effect. Incidence of perinatal death was higher in the progesterone group, although there was considerable uncertainty in the effect estimate and the quality of the evidence was low for this outcome (RR 1.23, 95% CI 0.74 to 2.06; infants = 2287; studies = 3; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (average RR 0.97, 95% CI 0.89 to 1.06; women = 1597; studies = 6; moderate-quality evidence); preterm birth less than 28 weeks (RR 1.53, 95% CI 0.79 to 2.97; women = 1345; studies = 3; low-quality evidence); infant birthweight less than 2500 g (average RR 0.95, 95% CI 0.84 to 1.07; infants = 2640; studies = 3; I² = 66%, moderate-quality evidence)). No childhood outcomes were reported in the trials. For secondary outcomes, there were no clear group differences found in any of the other maternal outcomes except for caesarean section, where women who received vaginal progesterone did not have as many caesarean sections as those in the placebo group, although the difference between groups was not large (8%) (RR 0.92, 95% CI 0.86 to 0.98; women = 1919; studies = 5; I² = 0%). There were no clear group differences found in any of the infant outcomes except for mechanical ventilation, which was required by fewer infants whose mothers had received the vaginal progesterone (RR 0.70, 95% CI 0.52 to 0.94; infants = 2695; studies = 4).

AUTHORS' CONCLUSIONS

Overall, for women with a multiple pregnancy, the administration of progesterone (either IM or vaginal) does not appear to be associated with a reduction in risk of preterm birth or improved neonatal outcomes. Future research could focus on a comprehensive individual participant data meta-analysis including all of the available data relating to both IM and vaginal progesterone administration in women with a multiple pregnancy, before considering the need to conduct trials in subgroups of high-risk women (for example, women with a multiple pregnancy and a short cervical length identified on ultrasound).

Practical considerations with 17-Hydroxyprogesterone caproate for preterm birth prevention: does timing of initiation and compliance matter?

OBJECTIVE

Determine whether gestational age of 17-hydroxyprogesterone caproate (17-OHPC) initiation is associated with preterm birth (PTB) risk.

STUDY DESIGN

We performed a retrospective cohort study using MarketScan® data. The primary outcome was PTB < 37 weeks. Rates of PTB were compared between medication initiation at 16-21 weeks versus 21-29 weeks. The association between compliance with weekly 17-OHPC injections and preterm birth rate was tested after adjusting for potential confounding variables.

RESULT

In all 3374 pregnancies met inclusion criteria. Women with an early 17-OHPC start were less likely to deliver preterm than those with a late start (aRR 0.88; 95%CI 0.79-0.97; p = 0.02). Less compliant patients receiving <25% of recommended doses had a higher PTB rate than those receiving >85% of recommended doses (aRR 1.5; 95%CI 1.2-1.7; p < 0.01).

CONCLUSION

There is an association between both early 17-OHPC initiation and compliance with reduced rates of PTB.

Adjuvant 17-hydroxyprogesterone caproate in women with history-indicated cerclage: A systematic review and meta-analysis

INTRODUCTION

The purpose of this study was to evaluate whether there are additional benefits of 17-hydroxyprogesterone caproate (17-OHPC) supplementation in preventing recurrent spontaneous preterm birth in women with a prophylactic cerclage.

MATERIAL AND METHODS

Electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, Scielo and the Cochrane Central Register of Controlled Trials) were searched for studies published before June 2018. Keywords included "preterm birth", "prophylactic cerclage", "history-indicated cerclage", "pregnancy" and "17-hydroxyprogesterone caproate". Studies comparing history-indicated cerclage alone with cerclage+17-OHPC were included. The primary outcome measure was preterm birth at <24 weeks of gestation. Secondary outcome measures include preterm birth at <28 weeks, <32 weeks and <37 weeks of gestation, respiratory distress syndrome, necrotizing enterocolitis, fetal birthweight, neonatal intensive care unit stay, mean gestational age at delivery, fetal/neonatal death, neurological morbidity (intraventricular hemorrhage plus periventricular leukomalacia), neonatal sepsis and a composite of severe neonatal morbidity. Severe neonatal morbidity was defined as a composite measure of periventricular leukomalacia, intraventricular hemorrhage (grades III and IV), necrotizing enterocolitis or respiratory distress syndrome. Meta-analysis was performed using the random-effects model of DerSimonian and Laird. Risk of bias and quality assessment were performed using the ROBINS-I and GRADE tools, respectively. PROSPERO Registration Number: CRD42018094559.

RESULTS

Five studies met the inclusion criteria and were included in the final analysis. Of the 546 women, 357 (75%) received history-indicated cerclage alone and 189 (35%) received adjuvant 17-OHPC. The composite endpoint, severe neonatal morbidity, was present in 84 of 1515 neonates. Though there was a trend toward a reduced risk of preterm birth, the summary estimate of effect was not statistically significant when comparing cerclage alone with cerclage+17-OHPC at <24 weeks (relative risk [RR] .86, 95% confidence interval [CI] .45-1.65). Similarly, we found no differences in preterm birth at <37 weeks (RR .90, 95% CI .70-1.17) and <28 weeks (RR .85, 95% CI .54-1.32) when comparing cerclage alone with cerclage+17-OHPC. There were no differences in fetal birthweight, respiratory distress syndrome or necrotizing enterocolitis comparing cerclage alone with cerclage+17-OHPC.

CONCLUSIONS

Intramuscular 17-OHPC in combination with prophylactic cerclage in women with prior preterm birth had no synergistic effect in reducing spontaneous recurrent preterm birth or improving perinatal outcomes.

Pharmacokinetics of Hydroxyprogesterone Caproate and its Primary Metabolites during Pregnancy

Objective  To measure pharmacokinetics of hydroxyprogesterone caproate (OHPC) and its major metabolites throughout pregnancy. Study Design  Thirty women were prescribed OHPC for recurrent preterm birth prevention. Three cohorts of subjects had blood drawn for 7 consecutive days at one of three times: cohort 1 ( n  = 6) after the first dose (weeks 16-20), cohort 2 ( n  = 8) between weeks 24 and 28, and cohort 3 ( n  = 16) between weeks 32 and 36. We measured serum trough levels after week 1 in cohort 1 or after two consecutive weekly doses in cohorts 2 and 3. In 10 subjects, we estimated OHPC terminal half-life at 28 days after their last dose. Results  In cohorts 1, 2, and 3, the areas under curve (ng × h/mL) for OHPC were 571.4 ± 195.2, 1,269.6 ± 285.0, and 1,268.0 ± 511.6, respectively. Maximum OHPC levels (ng/mL) were 5.0 ± 1.5, 12.5 ± 3.9, and 12.3 ± 4.9, respectively. The areas under the curve for mono-hydroxylated metabolites were 208.5 ± 92.4, 157.1 ± 64.6, and 211.2 ± 113.1, and maximum concentrations were 1.9 ± 0.7, 1.5 ± 0.7, and 1.8 ± 1.0, respectively. Di-hydroxylated metabolite levels were significantly lower than mono-hydroxylated metabolites. Estimated terminal half-life of OHPC was 16.3 ± 3.6 days and 19.7 ± 6.2 days for the mono-hydroxylated metabolites. Conclusion  After the first injection, OHPC maximum serum level was approximately half steady-state level. Measurable metabolites of unknown activity were detected.

In an in-vitro model using human fetal membranes, 17-α hydroxyprogesterone caproate is not an optimal progestogen for inhibition of fetal membrane weakening

BACKGROUND

The progestogen 17-α hydroxyprogesterone caproate (17-OHPC) is 1 of only 2 agents recommended for clinical use in the prevention of spontaneous preterm delivery, and studies of its efficacy have been conflicting. We have developed an in-vitro model to study the fetal membrane weakening process that leads to rupture in preterm premature rupture of the fetal membranes (pPROM). Inflammation/infection associated with tumor necrosis factor-α (TNF-α) induction and decidual bleeding/abruption associated thrombin release are leading causes of preterm premature rupture of the fetal membranes. Both agents (TNF-α and thrombin) cause fetal membrane weakening in the model system. Furthermore, granulocyte-macrophage colony-stimulating factor (GM-CSF) is a critical intermediate for both TNF-α and thrombin-induced fetal membrane weakening. In a previous report, we demonstrated that 3 progestogens, progesterone, 17-alpha hydroxyprogesterone (17-OHP), and medroxyprogesterone acetate (MPA), each inhibit both TNF-α- and thrombin-induced fetal membrane weakening at 2 distinct points of the fetal membrane weakening pathway. Each block both the production of and the downstream action of the critical intermediate granulocyte-macrophage colony-stimulating factor.

OBJECTIVE

The objective of the study was to characterize the inhibitory effects of 17-OHPC on TNF-α- and thrombin-induced fetal membrane weakening in vitro.

STUDY DESIGN

Full-thickness human fetal membrane fragments from uncomplicated term repeat cesarean deliveries were mounted in 2.5 cm Transwell inserts and cultured with/without 17-alpha hydroxyprogesterone caproate (10^-9 to 10^-7 M). After 24 hours, medium (supernatant) was removed and replaced with/without the addition of tumor necrosis factor-alpha (20 ng/mL) or thrombin (10 U/mL) or granulocyte-macrophage colony-stimulating factor (200 ng/mL). After 48 hours of culture, medium from the maternal side compartment of the model was assayed for granulocyte-macrophage colony-stimulating factor and the fetal membrane fragments were rupture strength tested.

RESULTS

Tumor necrosis factor-alpha and thrombin both weakened fetal membranes (43% and 62%, respectively) and increased granulocyte-macrophage colony-stimulating factor levels (3.7- and 5.9-fold, respectively). Pretreatment with 17-alpha hydroxyprogesterone caproate inhibited both tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening and concomitantly inhibited the induced increase in granulocyte-macrophage colony-stimulating factor in a concentration-dependent manner. However, contrary to our prior reports regarding progesterone and other progestogens, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced fetal membrane weakening.

CONCLUSION

17-Alpha hydroxyprogesterone caproate blocks tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening by inhibiting the production of granulocyte-macrophage colony-stimulating factor. However, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced weakening. We speculate that progestogens other than 17-alpha hydroxyprogesterone caproate may be more efficacious in preventing preterm premature rupture of the fetal membranes-related spontaneous preterm birth.

Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy

BACKGROUND

Multiple pregnancy is a strong risk factor for preterm birth, and more than 50% of women with a twin pregnancy will give birth prior to 37 weeks' gestation. Infants born preterm are recognised to be at increased risk of many adverse health outcomes, contributing to more than half of overall perinatal mortality. Progesterone is produced naturally in the body and has a role in maintaining pregnancy, although it is not clear whether administering progestogens to women with multiple pregnancy at high risk of early birth is effective and safe.

OBJECTIVES

To assess the benefits and harms of progesterone administration for the prevention of preterm birth in women with a multiple pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the administration of a progestogen by any route for the prevention of preterm birth in women with multiple pregnancy. We did not include quasi-randomised or cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports identified by the search for eligibility, extracted data, assessed risk of bias and graded the quality of the evidence.

MAIN RESULTS

We included 17 trials, which all compared either vaginal or intramuscular (IM) progesterone with a placebo or no treatment, and involved a total of 4773 women. The risk of bias for the majority of included studies was low, with the exception of four studies that had inadequate blinding, or significant loss to follow-up or both, or were not reported well enough for us to make a judgement. We graded the evidence low to high quality, with downgrading for statistical heterogeneity, design limitations in some of the studies contributing data, and imprecision of the effect estimate. 1 IM progesterone versus no treatment or placeboMore women delivered at less than 34 weeks' gestation in the IM progesterone group compared with placebo (risk ratio (RR) 1.54, 95% confidence interval (CI) 1.06 to 2.26; women = 399; studies = 2; low-quality evidence). Although the incidence of perinatal death in the progesterone group was higher, there was considerable uncertainty around the effect estimate and high heterogeneity between studies (average RR 1.45, 95% CI 0.60 to 3.51; infants = 3089; studies = 6; I2 = 71%; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up.There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (RR 1.05, 95% CI 0.98 to 1.13; women = 2010; studies = 5; high-quality evidence); preterm birth less than 28 weeks (RR 1.08, 95% CI 0.75 to 1.55; women = 1920; studies = 5; moderate-quality evidence); infant birthweight less than 2500 g (RR 0.99, 95% CI 0.90 to 1.08; infants = 4071; studies = 5; I2 = 76%, moderate-quality evidence)). No childhood outcomes were reported in the trials. 2 Vaginal progesterone versus no treatment or placebo by doseThere were no clear group differences in incidence of preterm birth before 34 weeks (average RR 0.83, 95% CI 0.63 to 1.09; women = 1727; studies = 6; I2 = 46%; low-quality evidence). Although fewer births before 34 weeks appeared to occur in the progesterone group, the CIs crossed the line of no effect. Incidence of perinatal death was higher in the progesterone group, although there was considerable uncertainty in the effect estimate and the quality of the evidence was low for this outcome (RR 1.23, 95% CI 0.74 to 2.06; infants = 2287; studies = 3; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up.There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (average RR 0.97, 95% CI 0.89 to 1.06; women = 1597; studies = 6; moderate-quality evidence); preterm birth less than 28 weeks (RR 1.22, 95% CI 0.68 to 2.21; women = 1569; studies = 4; low-quality evidence); infant birthweight less than 2500 g (RR 0.95, 95% CI 0.88 to 1.03; infants = 3079; studies = 4; I2 = 49%, moderate-quality evidence)). No childhood outcomes were reported in the trials.For secondary outcomes, there were no clear group differences found in any of the other maternal outcomes except for caesarean section, where women who received vaginal progesterone did not have as many caesarean sections as those in the placebo group, although the difference between groups was not large (7%) (RR 0.93, 95% CI 0.88 to 0.98; women = 2143; studies = 6; I2 = 0%). There were no clear group differences found in any of the infant outcomes except for mechanical ventilation, which was required by fewer infants whose mothers had received the vaginal progesterone (RR 0.61, 95% CI 0.48 to 0.77; infants = 3134; studies = 5).

AUTHORS' CONCLUSIONS

Overall, for women with a multiple pregnancy, the administration of progesterone (either IM or vaginal) does not appear to be associated with a reduction in risk of preterm birth or improved neonatal outcomes.Future research could focus on a comprehensive individual participant data meta-analysis including all of the available data relating to both IM and vaginal progesterone administration in women with a multiple pregnancy, before considering the need to conduct trials in subgroups of high-risk women (for example, women with a multiple pregnancy and a short cervical length identified on ultrasound).

17-α Hydroxyprogesterone Caproate for the Prevention of Recurrent Preterm Birth: One Size May Not Fit All

Spontaneous preterm birth is a syndrome with many causes and thus unresponsive to a single intervention. It logically follows that patients with a prior spontaneous preterm birth are a heterogeneous group unlikely to respond equally to a single preventive intervention such as 17-α hydroxyprogesterone caproate. Further confounding this issue is our fundamental lack of knowledge about the mechanism(s) by which 17-α hydroxyprogesterone caproate reduces preterm birth. Recently, studies demonstrating that responders and nonresponders can be identified based on obstetric history, genotype, physical characteristics, and behavioral factors have begun to provide clues into both 17-α hydroxyprogesterone caproate's mechanism and the pathophysiology of recurrent preterm birth and may allow for more targeted therapy. These studies lend support to speculation that inflammation or nitric oxide metabolism may be common threads between 17-α hydroxyprogesterone caproate's mechanism and preterm birth prevention. It will remain critically important to avoid the temptation to regard prior spontaneous preterm birth as a single disease entity amenable to a single treatment.

Smoking, 17 Alpha-Hydroxyprogesterone Caproate, and Preterm Birth

Objective The objective of this study was to determine if maternal smoking modifies the effectiveness of 17 α-hydroxyprogesterone caproate (17OHP-C). Study Design Secondary analysis of the Maternal-Fetal Medicine Units Network trial of 17OHP-C. The prevalence of preterm birth (PTB) by smoking status and treatment group was compared by chi-squared analysis and analysis of variance was used to compare gestational age (GA) at birth. Multivariable modeling was used to estimate the effect of smoking on 17OHP-C treatment. Results In this study, 459 women were included. Maternal smoking significantly modified the effectiveness of 17OHP-C treatment. In smokers, 17OHP-C significantly reduced the prevalence of multiple outcomes (PTB < 37 and < 35 weeks, spontaneous PTB < 37 and < 35 weeks), while in nonsmokers, only PTB < 37 weeks was reduced. Delivery GA was later in 17OHP-C versus placebo treated smokers (36.4 vs. 34.3 weeks, p = 0.041) but not nonsmokers (36.3 vs. 35.5 weeks, p = nonsignificant). In multivariable modeling, 17OHP-C was more effective in smokers than nonsmokers as measured by multiple outcomes (PTB < 37 weeks [p = 0.041] and < 35 weeks [p = 0.036] and spontaneous PTB < 37 weeks [p = 0.029]). Conclusion In this cohort of women with a prior PTB, maternal smoking status significantly modified the effectiveness of 17OHP-C treatment.

Racial and ethnic disparities in use of 17-alpha hydroxyprogesterone caproate for prevention of preterm birth

BACKGROUND

Racial/ethnic disparities in preterm birth remain a major public health challenge in the United States. While 17-alpha hydroxyprogesterone caproate (17OHP-C) is recommended for preterm birth prevention in women with a prior preterm birth, non-Hispanic black women continue to experience higher rates of recurrent preterm birth than white women receiving the same treatment. Further investigation of disparities in 17OHP-C use and adherence is warranted.

OBJECTIVE

We sought to evaluate whether racial and ethnic disparities exist in the use of and adherence to 17OHP-C within a population of eligible women.

STUDY DESIGN

This was a retrospective cohort study of women with a prior spontaneous, singleton preterm birth who were eligible for 17OHP-C for preterm birth prevention and received care at a single institution from 2010 through 2014. Associations between self-identified race/ethnicity (non-Hispanic black vs women in all other racial/ethnic groups) and documented counseling about 17OHP-C, receipt of any 17OHP-C, and adherence to 17OHP-C administration were each estimated by bivariable analysis and multivariable logistic regression. Adherence to 17OHP-C was defined as not >1 missed dose, initiation <20 weeks' gestational age, and continuation until 37 weeks or delivery.

RESULTS

Of 472 women who were clinically eligible for 17OHP-C, 72% (N = 296) had documented 17OHP-C counseling and 48.9% (N = 229) received 17OHP-C. There were no differences in likelihood of 17OHP-C counseling or receipt of 17OHP-C based on race/ethnicity. While overall 83% (N = 176) of women were adherent to 17OHP-C, only 70% (N = 58) of non-Hispanic black women were adherent, compared to 91% (N = 118) of all other women (P < .001). Non-Hispanic black women had more missed doses (2.4 vs 0.4 doses, P < .001) and later initiation of care (12.0 vs 10.2 weeks, P < .001) than women in other racial/ethnic groups. After adjustment for potential confounders, non-Hispanic black women were significantly less likely to be adherent to 17OHP-C (adjusted odds ratio, 0.16; 95% confidence interval, 0.04-0.65). A significant interaction between non-Hispanic black race/ethnicity and public insurance was identified (adjusted odds ratio, 0.16; 95% confidence interval, 0.05-0.52).

CONCLUSION

In a diverse cohort of women eligible for preterm birth prevention, non-Hispanic black women are at an increased risk of nonadherence to 17OHP-C. Non-Hispanic black women with public insurance are at a particularly increased risk of nonadherence.

17 α-hydroxyprogesterone caproate (Makena®): a guide to its use in the prevention of preterm birth

Intramuscular 17 α-hydroxyprogesterone caproate (Makena(®)), a synthetic progestin, is indicated to reduce the risk of preterm birth in women with a singleton pregnancy who have a history of a singleton spontaneous preterm birth. Makena(®) reduces the risk of preterm birth in this patient population, and is associated with improvements in certain fetal/neonatal outcomes. The use of this US FDA-approved formulation of 17 α-hydroxyprogesterone caproate reduces the inherent risks associated with the use of pharmacy-compounded formulations of the drug.

Prenatal administration of progesterone for preventing preterm birth in women considered to be at risk of preterm birth

BACKGROUND

Preterm birth is a major complication of pregnancy associated with perinatal mortality and morbidity. Progesterone for the prevention of preterm labour has been advocated.

OBJECTIVES

To assess the benefits and harms of progesterone for the prevention of preterm birth for women considered to be at increased risk of preterm birth and their infants.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (14 January 2013) and reviewed the reference list of all articles.

SELECTION CRITERIA

Randomised controlled trials, in which progesterone was given for preventing preterm birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated trials for methodological quality and extracted data.

MAIN RESULTS

Thirty-six randomised controlled trials (8523 women and 12,515 infants) were included. Progesterone versus placebo for women with a past history of spontaneous preterm birth Progesterone was associated with a statistically significant reduction in the risk of perinatal mortality (six studies; 1453 women; risk ratio (RR) 0.50, 95% confidence interval (CI) 0.33 to 0.75), preterm birth less than 34 weeks (five studies; 602 women; average RR 0.31, 95% CI 0.14 to 0.69), infant birthweight less than 2500 g (four studies; 692 infants; RR 0.58, 95% CI 0.42 to 0.79), use of assisted ventilation (three studies; 633 women; RR 0.40, 95% CI 0.18 to 0.90), necrotising enterocolitis (three studies; 1170 women; RR 0.30, 95% CI 0.10 to 0.89), neonatal death (six studies; 1453 women; RR 0.45, 95% CI 0.27 to 0.76), admission to neonatal intensive care unit (three studies; 389 women; RR 0.24, 95% CI 0.14 to 0.40), preterm birth less than 37 weeks (10 studies; 1750 women; average RR 0.55, 95% CI 0.42 to 0.74) and a statistically significant increase in pregnancy prolongation in weeks (one study; 148 women; mean difference (MD) 4.47, 95% CI 2.15 to 6.79). No differential effects in terms of route of administration, time of commencing therapy and dose of progesterone were observed for the majority of outcomes examined. Progesterone versus placebo for women with a short cervix identified on ultrasound Progesterone was associated with a statistically significant reduction in the risk of preterm birth less than 34 weeks (two studies; 438 women; RR 0.64, 95% CI 0.45 to 0.90), preterm birth at less than 28 weeks' gestation (two studies; 1115 women; RR 0.59, 95% CI 0.37 to 0.93) and increased risk of urticaria in women when compared with placebo (one study; 654 women; RR 5.03, 95% CI 1.11 to 22.78). It was not possible to assess the effect of route of progesterone administration, gestational age at commencing therapy, or total cumulative dose of medication. Progesterone versus placebo for women with a multiple pregnancy Progesterone was associated with no statistically significant differences for the reported outcomes. Progesterone versus no treatment/placebo for women following presentation with threatened preterm labour Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (one study; 70 infants; RR 0.52, 95% CI 0.28 to 0.98). Progesterone versus placebo for women with 'other' risk factors for preterm birth Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (three studies; 482 infants; RR 0.48, 95% CI 0.25 to 0.91).

AUTHORS' CONCLUSIONS

The use of progesterone is associated with benefits in infant health following administration in women considered to be at increased risk of preterm birth due either to a prior preterm birth or where a short cervix has been identified on ultrasound examination. However, there is limited information available relating to longer-term infant and childhood outcomes, the assessment of which remains a priority.Further trials are required to assess the optimal timing, mode of administration and dose of administration of progesterone therapy when given to women considered to be at increased risk of early birth.

Recurrent preterm birth in women treated with 17 α-hydroxyprogesterone caproate: the contribution of risk factors in the penultimate pregnancy

OBJECTIVE

Examine rates of recurrent, spontaneous preterm birth (PTB) in women treated prophylactically with 17 α-hydroxyprogesterone caproate (17P) when the penultimate PTB was due to preterm labor (PTL) or preterm premature rupture of the membranes (pPROM).

METHODS

Retrospective, descriptive, database study of 1183 singleton gestations that initiated prophylactic 17P at <21 weeks with a penultimate PTB. Primary outcomes examined were rates of recurrent PTB at <37 and <32 weeks' gestation in the PTL (n = 939) and pPROM (n = 244) cohorts.

RESULTS

Recurrent PTB <37 weeks occurred in 38% versus 28.3% of the PTL and pPROM cohorts, respectively (p <0.005). Rates of recurrent PTB <32 weeks were similar. Logistic regression revealed three risk factors increased the odds of recurrent PTB: >1 previous PTB (OR 1.8 [95% CI: 1.33-2.44]); penultimate birth at 28-33.9 weeks' gestation (OR 1.61 [95% CI: 1.22-2.13]); and, PTL as the indication for delivery in the penultimate PTB (OR 1.66 [95% CI: 1.16-2.37]).

CONCLUSION

Several historical factors increase the risk for recurrent PTB in women receiving 17P. Contrary to earlier studies of PTL and pPROM recurrence, women receiving prophylactic 17P with a penultimate PTB due to pPROM are at lower risk of recurrent PTB than those with a history of PTL.

17 α-Hydroxyprogesterone caproate (Makena™): in the prevention of preterm birth

17 α-hydroxyprogesterone caproate is a synthetic progestin of which there is now a US FDA-approved formulation available for intramuscular administration (Makena™) to reduce the risk of preterm birth. Intramuscular 17 α-hydroxyprogesterone caproate (identical in formulation and manufacturing process to Makena™, thus hereafter referred to as Makena™) 250 mg once weekly, initiated at 16-20 weeks' gestation, was effective in reducing the risk of preterm birth in women with a singleton pregnancy at high risk of delivering preterm in a large, well designed, placebo-controlled trial (n = 463 randomized). Rates of delivery before 37 (primary endpoint), 35, or 32 weeks' gestation were significantly lower with Makena™ than with placebo, corresponding to relative risk reductions of 34%, 33%, and 42%, respectively. The benefit of the drug in reducing the risk of preterm birth was observed when deliveries were spontaneous (but not when indicated because of complications) and regardless of maternal race. In addition, there was a significantly lower rate of several adverse fetal/neonatal outcomes among infants of women who received Makena™ than among infants of placebo recipients, including necrotizing enterocolitis, need for supplemental oxygen, birth weight of <2500 g, and intraventricular hemorrhage. Makena™ was generally well tolerated in pregnant women in this trial. Moreover, fetal exposure to the drug appeared to be safe according to a 2- to 5-year follow-up of the study, with no evidence of a detrimental effect of the drug on child neurodevelopment and a low overall incidence (≈2%) of reproductive or genital abnormalities that was not significantly different from placebo.

17-alphahydroxyprogesterone caproate in women with previous spontaneous preterm delivery: does a previous term delivery affect the rate of recurrence?

OBJECTIVE

The purpose of this study was to determine the role of previous term delivery on the rate of recurrent preterm birth in women with previous spontaneous preterm delivery (SPTD) who receive 17-alphahydroxyprogesterone caproate (17P) therapy.

STUDY DESIGN

Women with singleton gestations who were receiving 17P therapy were studied. Rates of recurrent SPTD were compared for 1 or ≥2 SPTD with and without a previous term delivery.

RESULTS

Five thousand one hundred two women had 1 previous SPTD, and 2217 women had ≥2 SPTDs. In women with 1 previous SPTD, a previous term delivery had lower rates of SPTD at <35 weeks (8.4% vs 11.2%; P = .002) and preterm delivery at <32 weeks (4.7% vs 6.2%; P = .027) compared with those women with no such history. No differences were found for SPTD at <35 weeks with ≥2 SPTDs.

CONCLUSION

In patients who received 17P therapy with 1 previous SPTD, a previous term delivery confers a reduction in risk of preterm delivery at <37, <35, and <32 weeks' gestation; such reduction is not evident with ≥2 previous SPTDs.

Universal cervical-length screening to prevent preterm birth: a cost-effectiveness analysis

OBJECTIVE

To determine whether routine measurement of second-trimester transvaginal cervical length by ultrasound in low-risk singleton pregnancies is a cost-effective strategy.

METHODS

We developed a decision analysis model to compare the cost-effectiveness of two strategies for identifying pregnancies at risk for preterm birth: (1) no routine cervical length screening and (2) a single routine transvaginal cervical length measurement at 18-24 weeks' gestation. In our model, women identified as being at increased risk (cervical length < 1.5 cm) for preterm birth would be offered daily vaginal progesterone supplementation. We assumed that vaginal progesterone reduces preterm birth at < 34 weeks' gestation by 45%. We also assumed that a decreased cervical length could result in additional costs (ultrasound scans, inpatient admission) without significantly improved neonatal outcomes. The main outcome measure was incremental cost-effectiveness ratio.

RESULTS

Our model predicts that routine cervical-length screening is a dominant strategy when compared to routine care. For every 100,000 women screened, $12,119,947 can be potentially saved (in 2010 US dollars) and 423.9 quality-adjusted life-years could be gained. Additionally, we estimate that 22 cases of neonatal death or long-term neurologic deficits could be prevented per 100,000 women screened. Screening remained cost-effective but was no longer the dominant strategy when cervical-length ultrasound measurement costs exceeded $187 or when vaginal progesterone reduced delivery risk at < 34 weeks by less than 20%.

CONCLUSION

In low-risk pregnancies, universal transvaginal cervical length ultrasound screening appears to be a cost-effective strategy under a wide range of clinical circumstances (varied preterm birth rates, predictive values of a shortened cervix and costs).

Gestational age at initiation of 17-hydroxyprogesterone caproate (17P) and recurrent preterm delivery

OBJECTIVE

To compare rates of recurrent preterm birth between women starting treatment with 17alpha-hydroxyprogesterone caproate (17P) at 16-20.9 weeks of gestation versus 21-26.9 weeks.

METHODS

Women enrolled in an outpatient program of education, nursing assessment and weekly 17P injections beginning at 16-26.9 weeks were eligible. Included were patients with singleton pregnancies and a history of preterm delivery (PTD). Pregnancy outcome was compared between women starting 17P at 16-20.9 weeks (n=156) and those starting 17P at 21-26.9 weeks (n=119) using Fisher's exact and Mann-Whitney U test statistics (p<0.05 considered significant).

RESULTS

Mean gestational age at delivery (36.8 +/- 3.0 vs. 36.7 +/- 2.5) and rates of PTD at <37 weeks (40.4% vs. 48.7%), <35 weeks (16.7% vs. 16.8%) and <32 weeks (5.1% vs. 5.0%) were similar between the groups; all p > 0.05.

CONCLUSIONS

Rates of preterm delivery were similar in patients initiating 17P at 16-20.9 or 21-26.9 weeks. A larger sample size is warranted in order to confirm our findings.

Salivary progesterone and estriol among pregnant women treated with 17-alpha-hydroxyprogesterone caproate or placebo

OBJECTIVE

The objectives of the study was to determine whether salivary progesterone (P) or estriol (E3) concentration at 16-20 weeks' gestation predicts preterm birth or the response to 17alpha-hydroxyprogesterone caproate (17OHPC) and whether 17OHPC treatment affected the trajectory of salivary P and E3 as pregnancy progressed.

STUDY DESIGN

This was a secondary analysis of a clinical trial of 17OHPC to prevent preterm birth. Baseline saliva was assayed for P and E3. Weekly salivary samples were obtained from 40 women who received 17OHPC and 40 who received placebo in a multicenter randomized trial of 17OHPC to prevent recurrent preterm delivery.

RESULTS

Both low and high baseline saliva P and E3 were associated with a slightly increased risk of preterm birth. However, 17OHPC prevented preterm birth comparably, regardless of baseline salivary hormone concentrations. 17OHPC did not alter the trajectory of salivary P over pregnancy, but it significantly blunted the rise in salivary E3 as well as the rise in the E3/P ratio.

CONCLUSION

17OHPC flattened the trajectory of E3 in the second half of pregnancy, suggesting that the drug influences the fetoplacental unit.

Redirection of cytokine production by lymphocytes from women with pre-term delivery by dydrogesterone

PROBLEM

To study the ability of dydrogesterone to modulate the production of pro-inflammatory and anti-inflammatory cytokines by lymphocytes from women undergoing pre-term delivery (PTD).

METHOD OF STUDY

Peripheral blood mononuclear cells (PBMC) from 18 subjects undergoing PTD were stimulated with the mitogen phytohemagglutinin in the presence and absence of progesterone and dydrogesterone. The levels of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 in culture supernatants were then estimated by enzyme-linked immunoabsorbant assay. Cytokine production in the presence and absence of progesterone and dydrogesterone were compared.

RESULTS

The exposure of PBMC to dydrogesterone resulted in a significant inhibition in the production of the pro-inflammatory cytokines IFN-gamma and TNF-alpha and a significant increase in the levels of the anti-inflammatory cytokine IL-4, resulting in a substantial shift in the ratio of Th1/Th2 cytokines.

CONCLUSION

Dydrogesterone induces a shift in cytokine bias, by inhibiting pro-inflammatory cytokine production and increasing anti-inflammatory cytokine production.

Subgroup analysis in obstetrics clinical trials

Although clinical trials report results in the aggregate, clinicians often wish to tailor treatments that are based on demographic, historic, clinical, or laboratory characteristics of their patients and are interested therefore in trial results that are presented separately according to such characteristics. Unfortunately, such subgroup analysis often are done incorrectly and often are misinterpreted, even when done correctly. Only subgroups that are defined by characteristics that are determined at or before the moment of randomization are valid. It is incorrect to determine whether treatment is effective among a subgroup of patients according to the probability value in that particular subgroup. The correct method uses a formal test for interaction. However, even when done correctly, most subgroup differences in treatment effectiveness prove to be spurious. A priori definition of the subgroup, strong supporting rationale, and, ultimately, replication in other studies increase confidence that subgroup differences are valid.

Recurrent preterm birth

Recurrent preterm birth is frequently defined as two or more deliveries before 37 completed weeks of gestation. The recurrence rate varies as a function of the antecedent for preterm birth: spontaneous versus indicated. Spontaneous preterm birth is the result of either preterm labor with intact membranes or preterm prelabor rupture of the membranes. This article reviews the body of literature describing the risk of recurrence of spontaneous and indicated preterm birth. Also discussed are the factors which modify the risk for recurrent spontaneous preterm birth (a short sonographic cervical length and a positive cervicovaginal fetal fibronectin test). Patients with a history of an indicated preterm birth are at risk not only for recurrence of this subtype, but also for spontaneous preterm birth. Individuals of black origin have a higher rate of recurrent preterm birth.

Impact of the recent randomized trials on the use of progesterone to prevent preterm birth: a 2005 follow-up survey

OBJECTIVE

The purpose of this study was to determine whether current attitudes regarding the use of progesterone to prevent preterm birth have changed since our last survey in 2003.

STUDY DESIGN

We mailed a 20 question survey to 1264 board certified Maternal-Fetal Medicine specialists in the United States between February and March of 2005 asking about their use and attitudes regarding progesterone to prevent preterm birth.

RESULTS

Five hundred and seventy-two surveys were returned (response rate of 45%). In 2005, 67% of respondents used progesterone to prevent SPTB, compared to 38% in 2003 (P < .001). Among users, 38% recommended progesterone for indications other than previous SPTB. Users were more concerned about lack of insurance coverage compared to nonusers but nonusers were more concerned about safety, efficacy, need for more data, and long-term neonatal effects.

CONCLUSION

Although the use of progesterone to prevent PTB has increased significantly since our last survey, there remain a substantial number of nonusers. Among users, many are using it for indications not yet proven in clinical trials. Current nonusers have higher levels of concerns compared to nonusers in the first survey and their major concern is the need for more data.

17α-hydroxyprogesterone Caproate for the Prevention of Preterm Delivery

OBJECTIVE

To evaluate whether the use of 17alpha-hydroxyprogesterone caproate for the prevention of recurrent preterm deliveries is cost-effective.

METHODS

Using decision-analysis modeling, we compared the cost-effectiveness of using 17alpha-hydroxyprogesterone caproate in four subgroups: 1) Prior preterm deliveries less than 32 weeks; 2) prior preterm deliveries 32-37 weeks; 3) prior term delivery; and 4) no prior delivery. Each subgroup was compared with a "no treatment" group. Costs included those for 17alpha-hydroxyprogesterone caproate, hospital admissions, and complications from preterm deliveries. The main outcome measures include cost per quality-adjusted life-year gained and the number of preterm deliveries prevented. Secondary outcomes include neonatal complications prevented. One-way and multiway sensitivity analyses were performed.

RESULTS

The use of 17alpha-hydroxyprogesterone caproate for the prevention of preterm deliveries result in cost-savings in women with prior preterm deliveries less than 32 weeks and 32-37 weeks. The sensitivity analyses revealed the model to be robust over a wide range of values for evaluated variables.

CONCLUSION

Within our baseline assumptions, 17alpha-hydroxyprogesterone caproate was associated with cost-savings when used for the prevention of preterm deliveries in women with prior preterm deliveries.

Prenatal administration of progesterone for preventing preterm birth

BACKGROUND

Preterm birth is the major complication of pregnancy associated with perinatal mortality and morbidity and occurs in up to 6% to 10% of all births. Administration of progesterone for the prevention of preterm labour has been advocated.

OBJECTIVES

To assess the benefits and harms of progesterone administration during pregnancy in the prevention of preterm birth.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Specialised Register of Controlled Trials (March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2004), MEDLINE (1965 to January 2005), EMBASE (1988 to August 2004), and Current Contents (1997 to August 2004).

SELECTION CRITERIA

All published and unpublished randomised controlled trials, in which progesterone was given by any route for preventing preterm birth.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Collaboration and the Cochrane Pregnancy and Childbirth Group were used. Evaluation of methodological quality and trial data extraction were undertaken independently by two authors. Results are presented using relative risk with 95% confidence intervals.

MAIN RESULTS

For all women administered progesterone, there was a reduction in the risk of preterm birth less than 37 weeks (six studies, 988 participants, relative risk (RR) 0.65, 95% confidence interval (CI) 0.54 to 0.79) and preterm birth less than 34 weeks (one study, 142 participants, RR 0.15, 95% CI 0.04 to 0.64). Infants born to mothers administered progesterone were less likely to have birthweight less than 2500 grams (four studies, 763 infants, RR 0.63, 95% CI 0.49 to 0.81) or intraventricular haemorrhage (one study, 458 infants, RR 0.25, 95% CI 0.08 to 0.82). There was no difference in perinatal death between women administered progesterone and those administered placebo (five studies, 921 participants, RR 0.66, 95% CI 0.37 to 1.19). There were no other differences reported for maternal or neonatal outcomes.

AUTHORS' CONCLUSIONS

Intramuscular progesterone is associated with a reduction in the risk of preterm birth less than 37 weeks' gestation, and infant birthweight less than 2500 grams. However, other important maternal and infant outcomes have been poorly reported to date, with most outcomes reported from a single trial only (Meis 2003). It is unclear if the prolongation of gestation translates into improved maternal and longer-term infant health outcomes. Similarly, information regarding the potential harms of progesterone therapy to prevent preterm birth is limited. Further information is required about the use of vaginal progesterone in the prevention of preterm birth.