17 Alpha-hydroxyprogesterone caproate for preterm prevention: issues in subgroup analysis

What now? A critical evaluation of over 20 years of clinical and research experience with 17-alpha hydroxyprogesterone caproate for recurrent preterm birth prevention

Spontaneous preterm birth is multifactorial, and underlying etiologies remain incompletely understood. Supplementation with progestogens, including 17-alpha hydroxyprogesterone caproate has been a mainstay of prematurity prevention strategies in the United States in the last 2 decades. Following a recent negative confirmatory trial, 17-alpha hydroxyprogesterone caproate was withdrawn from the US market and is currently available only through clinical research studies. This expert review summarized clinical and research data regarding the use of 17-alpha hydroxyprogesterone caproate in the United States from 2003 to 2023 for recurrent prematurity prevention. In 17-alpha hydroxyprogesterone caproate. The history of the use, mechanisms of action, clinical trial results, and efficacy by clinical and biologic criteria of 17-alpha hydroxyprogesterone caproate are presented. We report that disparate findings and conclusions between similarly designed rigorous studies may reflect differences in a priori risk and population incidence and extreme care should be taken in interpreting the studies and making decisions regarding efficacy of 17-alpha hydroxyprogesterone caproate for the prevention of preterm birth. The likelihood of improved obstetrical outcomes after receiving 17-alpha hydroxyprogesterone caproate may vary by clinical factors (eg, body mass index), plasma drug concentrations, and genetic factors, although the identification of individuals most likely to benefit remains imperfect. It is crucial for the medical community to recognize the importance of preserving the decades-long efforts invested in preventing recurrent preterm birth in the United States. Moreover, it is important that we thoroughly and thoughtfully evaluate 17-alpha hydroxyprogesterone caproate as a promising contender for future well-executed prematurity studies.

Cervical pessary to prevent preterm birth in asymptomatic high-risk women: a systematic review and meta-analysis

BACKGROUND

Randomized controlled trials that have assessed the efficacy of cervical pessary to prevent preterm birth in asymptomatic high-risk women have reported conflicting results.

OBJECTIVE

To evaluate the efficacy and safety of cervical pessary to prevent preterm birth and adverse perinatal outcomes in asymptomatic high-risk women.

DATA SOURCES

MEDLINE, EMBASE, POPLINE, CINAHL, and LILACS (from their inception to October 31, 2019), Cochrane databases, Google Scholar, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared cervical pessary with standard care (no pessary) or alternative interventions in asymptomatic women at high risk for preterm birth.

STUDY APPRAISAL AND SYNTHESIS METHODS

The systematic review was conducted according to the Cochrane Handbook guidelines. The primary outcome was spontaneous preterm birth <34 weeks of gestation. Secondary outcomes included adverse pregnancy, maternal, and perinatal outcomes. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Twelve studies (4687 women and 7167 fetuses/infants) met the inclusion criteria: 8 evaluated pessary vs no pessary in women with a short cervix, 2 assessed pessary vs no pessary in unselected multiple gestations, and 2 compared pessary vs vaginal progesterone in women with a short cervix. There were no significant differences between the pessary and no pessary groups in the risk of spontaneous preterm birth <34 weeks of gestation among singleton gestations with a cervical length ≤25 mm (relative risk, 0.80; 95% confidence interval, 0.43-1.49; 6 trials, 1982 women; low-quality evidence), unselected twin gestations (relative risk, 1.05; 95% confidence interval, 0.79-1.41; 1 trial, 1177 women; moderate-quality evidence), twin gestations with a cervical length <38 mm (relative risk, 0.75; 95% confidence interval, 0.41-1.36; 3 trials, 1128 women; low-quality evidence), and twin gestations with a cervical length ≤25 mm (relative risk; 0.72, 95% confidence interval, 0.25-2.06; 2 trials, 348 women; low-quality evidence). Overall, no significant differences were observed between the pessary and no pessary groups in preterm birth <37, <32, and <28 weeks of gestation, and most adverse pregnancy, maternal, and perinatal outcomes (low- to moderate-quality evidence for most outcomes). There were no significant differences in the risk of spontaneous preterm birth <34 weeks of gestation between pessary and vaginal progesterone in singleton gestations with a cervical length ≤25 mm (relative risk, 0.99; 95% confidence interval, 0.54-1.83; 1 trial, 246 women; low-quality evidence) and twin gestations with a cervical length <38 mm (relative risk, 0.73; 95% confidence interval, 0.46-1.18; 1 trial, 297 women; very low-quality evidence). Vaginal discharge was significantly more frequent in the pessary group than in the no pessary and vaginal progesterone groups (relative risks, ∼2.20; high-quality evidence).

CONCLUSION

Current evidence does not support the use of cervical pessary to prevent preterm birth or to improve perinatal outcomes in singleton or twin gestations with a short cervix and in unselected twin gestations.

Intramuscular progesterone in women with twins and a prior singleton spontaneous preterm birth

BACKGROUND

Although the use of 17-alpha-hydroxyprogesterone caproate is one of the most commonly used strategies to reduce the risk of preterm birth since its approval by the Food and Drug Administration in 2011, there has been controversy recently that there may be no benefit associated with its use in singleton pregnancies in women with a prior history of spontaneous preterm birth. However, very few of these investigations evaluated the use of intramuscular progesterone in twin pregnancies. A few studies that used 17-alpha-hydroxyprogesterone caproate in twin pregnancies had mainly included unselected twin pregnancies. Although a twin pregnancy is independently associated with an increased likelihood of preterm birth, the primary indication for the use of supplemental progesterone in pregnancy is prior history of spontaneous preterm birth. Therefore, our investigation of weekly intramuscular progesterone in twin pregnancies with this birth history best addresses this question using a selected cohort.

OBJECTIVE

To assess whether weekly 17-alpha-hydroxyprogesterone caproate prevents recurrent preterm birth in women with a current twin pregnancy and a prior singleton spontaneous preterm birth.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancy and a prior singleton spontaneous preterm birth in 2 institutions between January 2005 and December 2016. One group (intervention group) consisted of women who received weekly 17-alpha-hydroxyprogesterone caproate, whereas the other (control group) did not. The primary outcome was twin spontaneous preterm birth <34 weeks compared with odds ratio and adjusted odds ratio, adjusting for potential confounders. Secondary outcomes included composite neonatal morbidity such as respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, admission to the neonatal intensive care nursery, and fetal or neonatal death before hospital discharge.

RESULTS

A total of 79 patients were included; 27 women received weekly 17-alpha-hydroxyprogesterone caproate and 52 did not. There were no statistically significant differences in maternal demographics except for age. Spontaneous preterm birth <34 weeks occurred in 16 patients (59%) in the intervention group vs 24 (46%) in the control group (odds ratio, 1.69; 95% confidence interval, 0.68-4.54). Composite neonatal morbidity occurred in 20 pregnancies (74%) in the intervention group and 41 pregnancies (79%) in the control group (odds ratio, 0.76; 95% confidence interval, 0.27-2.12). There remained no differences in outcomes after adjusting for potential confounders.

CONCLUSION

In our study, weekly 17-alpha-hydroxyprogesterone caproate did not prevent spontaneous preterm birth or neonatal morbidity in women with twins and a prior singleton spontaneous preterm birth; however, further research with larger numbers and prospective design is needed.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Nonresponse to 17-alpha hydroxyprogesterone caproate for recurrent spontaneous preterm birth prevention: clinical prediction and generation of a risk scoring system

BACKGROUND

Spontaneous preterm birth remains a leading cause of neonatal morbidity and mortality among nonanomalous neonates in the United States. Spontaneous preterm birth tends to recur at similar gestational ages. Intramuscular 17-alpha hydroxyprogesterone caproate reduces the risk of recurrent spontaneous preterm birth. Unfortunately, one-third of high-risk women will have a recurrent spontaneous preterm birth despite 17-alpha hydroxyprogesterone caproate therapy; the reasons for this variability in response are unknown.

OBJECTIVE

We hypothesized that clinical factors among women treated with 17-alpha hydroxyprogesterone caproate who suffer recurrent spontaneous preterm birth at a similar gestational age differ from women who deliver later, and that these associations could be used to generate a clinical scoring system to predict 17-alpha hydroxyprogesterone caproate response.

STUDY DESIGN

Secondary analysis of a prospective, multicenter, randomized controlled trial enrolling women with ≥1 previous singleton spontaneous preterm birth <37 weeks' gestation. Participants received daily omega-3 supplementation or placebo for the prevention of recurrent preterm birth; all were provided 17-alpha hydroxyprogesterone caproate. Women were classified as a 17-alpha hydroxyprogesterone caproate responder or nonresponder by calculating the difference in delivery gestational age between the 17-alpha hydroxyprogesterone caproate-treated pregnancy and her earliest previous spontaneous preterm birth. Responders were women with pregnancy extending ≥3 weeks later compared with the delivery gestational age of their earliest previous preterm birth; nonresponders delivered earlier or within 3 weeks of the gestational age of their earliest previous preterm birth. A risk score for nonresponse to 17-alpha hydroxyprogesterone caproate was generated from regression models via the use of clinical predictors and was validated in an independent population. Data were analyzed with multivariable logistic regression.

RESULTS

A total of 754 women met inclusion criteria; 159 (21%) were nonresponders. Responders delivered later on average (37.7±2.5 weeks) than nonresponders (31.5±5.3 weeks), P<.001. Among responders, 27% had a recurrent spontaneous preterm birth (vs 100% of nonresponders). Demographic characteristics were similar between responders and nonresponders. In a multivariable logistic regression model, independent risk factors for nonresponse to 17-alpha hydroxyprogesterone caproate were each additional week of gestation of the earliest previous preterm birth (odds ratio, 1.23; 95% confidence interval, 1.17-1.30, P<.001), placental abruption or significant vaginal bleeding (odds ratio, 5.60; 95% confidence interval, 2.46-12.71, P<.001), gonorrhea and/or chlamydia in the current pregnancy (odds ratio, 3.59; 95% confidence interval, 1.36-9.48, P=.010), carriage of a male fetus (odds ratio, 1.51; 95% confidence interval, 1.02-2.24, P=.040), and a penultimate preterm birth (odds ratio, 2.10; 95% confidence interval, 1.03-4.25, P=.041). These clinical factors were used to generate a risk score for nonresponse to 17-alpha hydroxyprogesterone caproate as follows: black +1, male fetus +1, penultimate preterm birth +2, gonorrhea/chlamydia +4, placental abruption +5, earliest previous preterm birth was 32-36 weeks +5. A total risk score >6 was 78% sensitive and 60% specific for predicting nonresponse to 17-alpha hydroxyprogesterone caproate (area under the curve=0.69). This scoring system was validated in an independent population of 287 women; in the validation set, a total risk score >6 performed similarly with a 65% sensitivity, 67% specificity and area under the curve of 0.66.

CONCLUSIONS

Several clinical characteristics define women at risk for recurrent preterm birth at a similar gestational age despite 17-alpha hydroxyprogesterone caproate therapy and can be used to generate a clinical risk predictor score. These data should be refined and confirmed in other cohorts, and women at high risk for nonresponse should be targets for novel therapeutic intervention studies.

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.

Vaginal progesterone decreases preterm birth ≤ 34 weeks of gestation in women with a singleton pregnancy and a short cervix: an updated meta-analysis including data from the OPPTIMUM study

OBJECTIVE

To evaluate the efficacy of vaginal progesterone administration for preventing preterm birth and perinatal morbidity and mortality in asymptomatic women with a singleton gestation and a mid-trimester sonographic cervical length (CL) ≤ 25 mm.

METHODS

This was an updated systematic review and meta-analysis of randomized controlled trials comparing the use of vaginal progesterone to placebo/no treatment in women with a singleton gestation and a mid-trimester sonographic CL ≤ 25 mm. Electronic databases, from their inception to May 2016, bibliographies and conference proceedings were searched. The primary outcome measure was preterm birth ≤ 34 weeks of gestation or fetal death. Two reviewers independently selected studies, assessed the risk of bias and extracted the data. Pooled relative risks (RRs) with 95% confidence intervals (CI) were calculated.

RESULTS

Five trials involving 974 women were included. A meta-analysis, including data from the OPPTIMUM study, showed that vaginal progesterone significantly decreased the risk of preterm birth ≤ 34 weeks of gestation or fetal death compared to placebo (18.1% vs 27.5%; RR, 0.66 (95% CI, 0.52-0.83); P = 0.0005; five studies; 974 women). Meta-analyses of data from four trials (723 women) showed that vaginal progesterone administration was associated with a statistically significant reduction in the risk of preterm birth occurring at < 28 to < 36 gestational weeks (RRs from 0.51 to 0.79), respiratory distress syndrome (RR, 0.47 (95% CI, 0.27-0.81)), composite neonatal morbidity and mortality (RR, 0.59 (95% CI, 0.38-0.91)), birth weight < 1500 g (RR, 0.52 (95% CI, 0.34-0.81)) and admission to the neonatal intensive care unit (RR, 0.67 (95% CI, 0.50-0.91)). There were no significant differences in neurodevelopmental outcomes at 2 years of age between the vaginal progesterone and placebo groups.

CONCLUSION

This updated systematic review and meta-analysis reaffirms that vaginal progesterone reduces the risk of preterm birth and neonatal morbidity and mortality in women with a singleton gestation and a mid-trimester CL ≤ 25 mm, without any deleterious effects on neurodevelopmental outcome. Clinicians should continue to perform universal transvaginal CL screening at 18-24 weeks of gestation in women with a singleton gestation and to offer vaginal progesterone to those with a CL ≤ 25 mm. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.