Risk Of Recurrent Preterm Birth Research Articles

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

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. 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. 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. 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. 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.

Utilization of 17-Alpha-Hydroxyprogesterone Caproate in a Medicaid Population [16D

INTRODUCTION: Preterm birth is the leading cause of neonatal mortality in the United States and contributes significantly to short- and long-term neonatal morbidity. Weekly 17-alpha-hydroxyprogesterone caproate (17P) injections effectively decrease the risk of recurrent preterm birth (PTB). Despite strong evidence supporting its use, 17P remains underutilized. Data regarding administration of 17P in Medicaid populations is limited. We sought to determine the utilization of 17P in a Texas Medicaid population. METHODS: The ICD-9 diagnosis code v23.41 (pregnancy with history of PTB) was used to identify all potential 17P candidates receiving prenatal care at two large Medicaid clinics. Each clinic has dedicated OB Care Coordinators for management of patients with prior PTB. Charts were reviewed to determine utilization and timing of 17P administration. RESULTS: Eighty-one patients were identified using the administrative code. Of these patients, 71.6% had a prior spontaneous preterm birth and were therefore eligible to receive 17P. Of the 58 eligible patients, the utilization rate was 62.1% (N=36). Gestational age at initiation of 17P ranged from 16 to 24.6 weeks with 66.7% (N=24) initiating prior to 20 weeks. Eligible patients did not receive 17P due to late entry into prenatal care (15.5%), pregnancy loss (5.2%), transfer from the practice (6.9%) and patient refusal of 17P (10.3%). CONCLUSION: Despite a concerted program to maximize 17P administration in a Medicaid population, this important medical intervention remained underutilized. Opportunities to increase administration of 17P include early enrollment into prenatal care and educational initiatives to reduce patient refusal.

606: Risk of recurrent preterm birth among women according to change in paternity

606: Risk of recurrent preterm birth among women according to change in paternity

Predictors of response to 17-alpha hydroxyprogesterone caproate for prevention of recurrent spontaneous preterm birth

Prematurity is the leading cause of neonatal morbidity and death among nonanomalous neonates in the United States. Intramuscular 17-alpha hydroxyprogesterone caproate injections reduce the risk of recurrent prematurity by approximately one third. Unfortunately, prophylactic 17-alpha hydroxyprogesterone caproate is not always effective, and one-third of high-risk women will have a recurrent preterm birth, despite 17-alpha hydroxyprogesterone caproate therapy. The reasons for this variability in response are unknown. Previous investigators have examined the influence of a variety of factors on 17-alpha hydroxyprogesterone caproate response but have analyzed data that used a fixed outcome of term delivery to define progesterone response. We hypothesized that the demographics, history, and pregnancy course among women who deliver at a similar gestational age with 17-alpha hydroxyprogesterone caproate for recurrent spontaneous preterm birth prevention differs when compared with those women who deliver later with 17-alpha hydroxyprogesterone caproate and that these associations could be refined by the use of a contemporary definition of 17-alpha hydroxyprogesterone caproate "responder." This was a planned secondary analysis of a prospective, multicenter, longitudinal study of women with ≥1 previous documented singleton spontaneous preterm birth at <37 weeks gestation. Data were collected at 3 prespecified gestational age epochs during pregnancy. All women who were included in this analysis received 17-alpha hydroxyprogesterone caproate during the studied pregnancy. We classified women 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 spontaneous preterm birth. Responders were defined as those with pregnancy that extended ≥3 weeks later with 17-alpha hydroxyprogesterone caproate, compared with the delivery gestational age of their earliest previous spontaneous preterm birth. Data were analyzed with the use of chi-square test, t-test, and logistic regression. One hundred fifty-five women met the inclusion criteria. The 118 responders delivered later on average (37.7 weeks gestation) than the 37 nonresponders (33.5 weeks gestation; P < .001). Among responders, 32% (38/118 women) had a recurrent spontaneous preterm birth. Demographics (age, race/ethnicity, education, and parity) were similar between groups. In the regression model, the gestational age of the previous spontaneous preterm birth (odds ratio, 0.68; 95% confidence interval, 0.56-0.82; P < .001), vaginal bleeding/abruption in the current pregnancy (odds ratio, 0.24; 95% confidence interval, 0.06-0.88; P = .031), and first-degree family history of spontaneous preterm birth (odds ratio, 0.37; 95% confidence interval, 0.15-0.88; P = .024) were associated with response to 17-alpha hydroxyprogesterone caproate. Because women with a penultimate preterm pregnancy were more likely to be 17-alpha hydroxyprogesterone caproate nonresponders, we performed an additional limited analysis examining only the 130 women whose penultimate pregnancy was preterm. In regression models, the results were similar to those in the main cohort. Several historic and current pregnancy characteristics define women who are at risk for recurrent preterm birth at a similar gestational age, despite 17-alpha hydroxyprogesterone caproate therapy. These data should be studied prospectively in larger cohorts and combined with genetic and environmental data to identify women who are most likely to benefit from this intervention.

Effect of cervical cerclage on rate of cervical shortening.

Although cerclage has been shown to reduce the risk of recurrent preterm birth in a high-risk patient population, the mechanism by which this occurs is not well understood. Our objective was to evaluate whether cerclage affects the rate of cervical shortening taking into account exposure to 17-hydroxyprogesterone and vaginal progesterone. This was a retrospective cohort study of women who had serial cervical length measurements due to a history of spontaneous preterm delivery. Demographic data, obstetric history, progesterone administration, delivery information and serial cervical length measurements were collected. The rate of cervical shortening was compared in women with and without cerclage. Subgroup analyses were performed to compare rates of cervical shortening by indication for cerclage (history indicated vs ultrasound indicated) and outcome in the current pregnancy (cerclage vs no cerclage among those who delivered preterm). A total of 414 women were included of whom 32.4% (n = 134) had a cerclage. There was no difference in the rate of cervical shortening between the cerclage (0.8 mm/week) and no-cerclage (1.0 mm/week, P = 0.43) groups. The rates of cervical shortening among history-indicated and ultrasound-indicated cerclage groups were similar (0.9 vs 1.3 mm/week, respectively, P = 0.2). Among patients with a preterm delivery in the index pregnancy, the rates of cervical shortening among those with (1.31 mm/week) and without (1.28 mm/week, P = 0.78) cerclage were also similar. Cervical shortening among women with cerclage occurs at a similar rate to that among women without a cerclage, regardless of indication for cerclage or pregnancy outcome.

Patient characteristics associated with 17-alpha hydroxyprogesterone caproate use among a high-risk cohort

Preterm birth (PTB) remains a significant cause of neonatal morbidity and mortality. Women with a prior PTB are at risk for recurrent PTB. Treatment with 17-alpha hydroxyprogesterone caproate (17OHP-C) has become standard of care for women with prior PTB to help reduce this risk. Factors that affect a woman's decision to use this medication are largely unknown. The objective of our study was to investigate patient-level barriers to 17OHP-C. We studied a cohort of women eligible for 17OHP-C with the hypothesis that 17OHP-C is underutilized and certain patient characteristics, such as obstetrical history, influence its use. A cross-sectional study of all women seen at a specialty prematurity clinic from 2009 through 2013 was performed. Women with a singleton pregnancy were included if they had a prior spontaneous PTB (sPTB). The χ(2) tests were performed for univariate analyses. Multivariable logistic regression was used to control for confounders. In all, 243 women had 17OHP-C recommended to them based on obstetrical history. There were 218 women with a pregnancy during our study period that were included in our analysis. A total of 163 (74.7%) had documented 17OHP-C use. Women were more likely to accept 17OHP-C if they had a history of a second-trimester loss only (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.17-4.58) or received recommendation for cerclage due to a short cervical length (OR, 4.12; 95% CI, 1.55-10.99). Women with a prior full-term birth were less likely to accept 17OHP-C (OR, 0.48; 95% CI, 0.26-0.89), especially when the prior full-term birth was subsequent rather than prior to the PTB (OR, 0.19; 95% CI, 0.08-0.47). Race, obesity, and insurance status did not impact 17OHP-C use. There was no difference in the rate of sPTB between those who used and did not use 17OHP-C (37.2 vs 34.0%, P = .7). Obstetric history impacted 17OHP-C use. This study identifies biases regarding 17OHP-C at the patient level and can be used to develop strategies to increase its use. However, the similarity in the sPTB rate between users and nonusers highlights the importance of identifying specific populations where 17OHP-C is and is not effective in preventing PTB.

Does the clinical presentation of a prior preterm birth predict risk in a subsequent pregnancy?

The objective of the study was to determine whether risk of recurrent preterm birth differs based on the clinical presentation of a prior spontaneous preterm birth (SPTB): advanced cervical dilatation (ACD), preterm premature rupture of membranes (PPROM), or preterm labor (PTL). This retrospective cohort study included singleton pregnancies from 2009 to 2014 complicated by a history of prior SPTB. Women were categorized based on the clinical presentation of their prior preterm delivery as having ACD, PPROM, or PTL. Risks for sonographic short cervical length and recurrent SPTB were compared between women based on the clinical presentation of their prior preterm birth. Log-linear regression was used to control for confounders. Of 522 patients included in this study, 96 (18.4%) had prior ACD, 246 (47.1%) had prior PPROM, and 180 (34.5%) had prior PTL. Recurrent PTB occurred in 55.2% of patients with a history of ACD compared with 27.2% of those with PPROM and 32.2% with PTL (P = .001). The mean gestational age at delivery was significantly lower for those with a history of ACD (34.0 weeks) compared with women with prior PPROM (37.2 weeks) or PTL (37.0 weeks) (P = .001). The lowest mean cervical length prior to 24 weeks was significantly shorter in patients with a history of advanced cervical dilation when compared with the other clinical presentations. Patients with a history of ACD are at an increased risk of having recurrent preterm birth and cervical shortening in a subsequent pregnancy compared with women with prior preterm birth associated PPROM or PTL.

Relation of body mass index to frequency of recurrent preterm birth in women treated with 17-alpha hydroxyprogesterone caproate

The standard weekly dose of 17-alpha hydroxyprogesterone caproate (17OHP-C; 250 mg/wk) to reduce the risk of recurrent preterm birth was adopted without regard to patient characteristics. We examined the relationship between prepregnancy body mass index (BMI) and gestational age at birth after 17OHP-C prophylaxis. We hypothesized that rates of births before 32, 35, and 37 weeks of gestation would be increased in women with a BMI of 25 kg/m(2) or greater. A retrospective cohort study was conducted from a deidentified database of women treated with 17OHP-C for prior spontaneous preterm birth. The frequency of recurrent preterm delivery before 32, 35, and 37 weeks of gestation was investigated for women with a BMI less than 25 kg/m(2) compared with women with a BMI of 25 kg/m(2) or greater. The adjusted relative risk of preterm delivery was estimated through a modified Poisson regression approach. Of 390 women who met inclusion criteria, 60 (15.4%) delivered before 32 weeks, 89 (22.8%) before 35 weeks, and 156 (40.0%) before 37 weeks. A total of 174 women had a BMI less than 25 kg/m(2) (mean [SD], 21.2 [2.5]) and 216 had a BMI of 25 kg/m(2) or greater (mean [SD], 33.5 [6.7]). Risk of birth before 32 weeks was 1.7 times higher on average (adjusted relative risk, 1.7; 95% confidence interval, 1.05-2.77) in overweight women than in women with a BMI less than 25 kg/m(2), adjusting for age, race, smoking, and short cervix. There was no difference in the risk of preterm birth before 35 or 37 weeks. Among pregnant women receiving 17OHP-C prophylaxis for a prior preterm birth, recurrent preterm birth before 32 weeks was significantly more common in those women whose prepregnancy BMI was 25 kg/m(2) or greater than in women with BMI less than 25 kg/m(2). This observation is consistent with pharmacological studies suggesting that dosing regimens of 17OHP-C may affect efficacy.

17α-Hydroxyprogesterone Caproate Access in the Louisiana Medicaid Population

Preterm birth and its associated neonatal morbidities remain pertinent health care and economic issues in the United States. Progesterone supplementation in the form of 17α-hydroxyprogesterone caproate has been reported to reduce the risk for recurrent preterm birth in women with a prior spontaneous preterm delivery, but several barriers contribute to its underutilization. The Affordable Care Act has increased the number of women receiving insurance coverage for pre- and perinatal care. However, the increase in insurance coverage has not necessarily facilitated access to standard therapies such as progesterone for the prevention of preterm birth. Data from Louisiana illustrate this point, and the state has responded by developing educational programs and the nation’s first pay-for-performance strategy targeting the initiation of progesterone therapy.

875: Prior full term birth does not decrease the risk of recurrent preterm birth

While it is known that a prior spontaneous preterm birth (sPTB) significantly increases the risk for recurrent sPTB, it remains unknown whether a prior full term birth (FTB) modifies that risk. Our objective was to determine the impact of a prior FTB on recurrent sPTB risk.

771: Can cervical length and obstetric history identify asymptomatic women at low risk for preterm birth after a previous preterm birth: a re-analysis of individual patient data

Women with a prior spontaneous preterm birth (PSPTB) are considered to be at high risk for recurrent preterm birth. We investigated whether cervical length (CL) and details of their PSPTB could stratify women into risk groups and identify a subgroup at low risk for recurrent preterm birth.

724: Fetal metabolism of progesterone: effect of proposed metabolites on uterine contractility

Progesterone may decrease the risk of recurrent preterm birth by directly inhibiting uterine contractility. The objective of this study was to characterize the effect of proposed fetal metabolites of progesterone on spontaneous and oxytocin-induced uterine contractility.

Do placental histologic findings of chorion-decidual hemorrhage or inflammation in spontaneous preterm birth influence outcomes in the subsequent pregnancy?

IntroductionSpontaneous preterm birth (SPTB) is the common endpoint of different underlying etiologies, including chorion-decidual bleeding and inflammation. However, specific histologic findings from a prior pregnancy do not always inform clinical management in subsequent pregnancies secondary to few prior studies having evaluated the relationship between prior pregnancy pathology and subsequent outcomes in patients with SPTB. MethodsIncluded subjects had: 1) a SPTB with available placental pathology and 2) a subsequent consecutive delivery at >20 weeks gestational age at our institution. For included subjects archived placenta and membrane paraffin blocks from the index SPTB were cut, stained with Prussian Blue and evaluated by a perinatal pathologist for the presence of hemosiderin. The association between histologic findings and subsequent pregnancy outcomes were evaluated through logistic and linear regression. ResultsA total of 131 subjects were included, of whom 39.7% had a recurrent SPTB. Funisitis at the time of preterm delivery significantly increased the risk of early (<34 weeks) recurrent preterm birth (OR 3.38, p = 0.016), though this may have been confounded by gestational age at delivery. Several histologic features were significantly associated with reductions in birth weight in the subsequent pregnancies, even if they did not increase the risk of recurrent preterm birth. DiscussionThe presence of chorion-decidual bleeding or inflammation in a prior pregnancy can signal an increased risk in a future pregnancy beyond the recurrent risk of SPTB itself. ConclusionsPlacental histologic findings after SPTB maybe associated with differences in birth weight in a subsequent pregnancy.

Recurrence of preterm birth and perinatal mortality in northern Tanzania: registry-based cohort study.

ObjectivesTo estimate the recurrence risk of preterm delivery and estimate the perinatal mortality in repeated preterm deliveries.MethodsProspective study in Tanzania of 18 176 women who delivered a singleton between 2000 and 2008 at KCMC hospital. The women were followed up to 2010 for consecutive births. A total of 3359 women were identified with a total of 3867 subsequent deliveries in the follow-up period. Recurrence risk of preterm birth and perinatal mortality was estimated using log-binomial regression and adjusted for potential confounders.ResultsFor women with a previous preterm birth, the risk of preterm birth in a subsequent pregnancy was 17%. This recurrence risk was estimated to be 2.7-fold (95% CI: 2.1–3.4) of the risk of women with a previous term birth. The perinatal mortality of babies in a second preterm birth of the same woman was 15%. Babies born at term who had an older sibling that was born preterm had a perinatal mortality of 10%. Babies born at term who had an older sibling who was also born at term had a perinatal mortality of 1.7%.ConclusionPrevious delivery of a preterm infant is a strong predictor of future preterm births in Tanzania. Previous or repeated preterm births increase the risk of perinatal death substantially in the subsequent pregnancy.

Association between body mass index and pregnancy outcome in a randomized trial of cerclage for short cervix.

To evaluate whether increasing body mass index (BMI) alters the efficacy of ultrasound-directed cerclage in women with a history of preterm birth. This was a planned secondary analysis of a multicenter trial in which women with a singleton gestation and prior spontaneous preterm birth (17 to 33 + 6 weeks' gestation) were screened for a short cervix by serial transvaginal ultrasound evaluations between 16 and 22 + 6 weeks. Women with a short cervix (cervical length < 25 mm) were randomly assigned to cerclage or not. Linear and logistic regression were used to assess the relationship between BMI and continuous and categorical variables, respectively. Overall, in the screened women (n = 986), BMI was not associated with cervical length (P = 0.68), gestational age at delivery (P = 0.12) or birth at < 35 weeks (P = 0.68). For the cerclage group (n = 148), BMI had no significant effect. For the no-cerclage group (n = 153), BMI was associated with a decrease in gestational age at delivery, with an estimated slope of - 0.14 weeks per kg/m(2) (P = 0.03; including adjustment for cervical length). This result was driven primarily by several women with BMI > 47 kg/m(2) . In women at high risk for recurrent preterm birth, BMI was not associated with cervical length or gestational age at birth. BMI did not appear to adversely affect ultrasound-indicated cerclage.

Re: Association between body mass index and pregnancy outcome in a randomized trial of cerclage for short cervix. C. K. Farinelli, D. A. Wing, J. M. Szychowski, J. Owen, G. Hankins, J. D. Iams, J. S. Sheffield, A. Perez‐Delboy, V. Berghella and E. R. Guzman; for the Vaginal Ultrasound Trial Consortium. Ultrasound Obstet Gynecol 2012; 40: 669–673

Linked Comment: Ultrasound Obstet Gynecol 2012:40:669‐673

Recurrence risk of preterm birth in subsequent twin pregnancy after preterm singleton delivery

To determine the risk of preterm birth in a subsequent twin pregnancy after previous singleton preterm birth. Cohort study. Nationwide study in the Netherlands. In all, 4071 nulliparous women who had a singleton delivery followed by a subsequent twin delivery between the years 1999 and 2007 were studied. Outcome of subsequent twin pregnancy of women with a history of preterm singleton delivery was compared with pregnancy outcome of women with a history of term singleton delivery. First deliveries were subdivided into iatrogenic and spontaneous preterm deliveries. Furthermore analyses were performed by subgroups for gestational age at the time of singleton delivery. Spontaneous preterm birth (<37 weeks of gestation) in subsequent twin pregnancy. In the index singleton pregnancy, preterm birth occurred in 232 (5.7%) of 4071 women. The risk of subsequent twin preterm birth was significantly higher after previous singleton preterm delivery (56.9 versus 20.9%; odds ratio 5.0; 95% CI 3.8-6.6). Risk of subsequent twin preterm birth was dependent on the severity of previous singleton preterm birth and was highest after preceding spontaneous instead of iatrogenic singleton preterm delivery. Preterm birth of a singleton gestation is associated with an increased risk of spontaneous preterm birth in a subsequent twin pregnancy.

Early preterm delivery due to placenta previa is an independent risk factor for a subsequent spontaneous preterm birth

BackgroundTo determine whether patients with placenta previa who delivered preterm have an increased risk for recurrent spontaneous preterm birth.MethodsThis retrospective population based cohort study included patients who delivered after a primary cesarean section (n = 9983). The rate of placenta previa, its recurrence, and the risk for recurrent preterm birth were determined.ResultsPatients who had a placenta previa at the primary CS pregnancy had an increased risk for its recurrence [crude OR of 2.65 (95% CI 1.3-5.5)]. The rate of preterm birth in patients with placenta previa in the primary CS pregnancy was 55.9%; and these patients had a higher rate of recurrent preterm delivery than the rest of the study population (p < .001). Among patients with placenta previa in the primary CS pregnancy, those who delivered preterm had a higher rate of recurrent spontaneous preterm birth regardless of the location of their placenta in the subsequent delivery [OR 3.09 (95% CI 2.1-4.6)]. In comparison to all patients with who had a primary cesarean section, patients who had placenta previa and delivered preterm had an independent increased risk for recurrent preterm birth [OR of 3.6 (95% CI 1.5-8.5)].ConclusionsWomen with placenta previa, who deliver preterm, especially before 34 weeks of gestation, are at increased risk for recurrent spontaneous preterm birth regardless to the site of placental implantation in the subsequent pregnancy. Thus, strict follow up by high risk pregnancies specialist is recommended.

Recurrence risk of preterm birth in subsequent singleton pregnancy after preterm twin delivery

The purpose of this study was to investigate the recurrence risk of preterm birth (<37 weeks' gestation) in a subsequent singleton pregnancy after a previous nulliparous preterm twin delivery. We included 1957 women who delivered a twin gestation and a subsequent singleton pregnancy from the Netherlands Perinatal Registry. We compared the outcome of subsequent singleton pregnancy of women with a history of preterm delivery to the pregnancy outcome of women with a history of term twin delivery. Preterm birth in the twin pregnancy occurred in 1075 women (55%) vs 882 women (45%) who delivered at term. The risk of subsequent spontaneous singleton preterm birth was significantly higher after preterm twin delivery (5.2% vs 0.8%; odds ratio, 6.9; 95% confidence interval, 3.1-15.2). Women who deliver a twin pregnancy are at greater risk for delivering prematurely in a subsequent singleton pregnancy.

17-α Hydroxyprogesterone Caproate for the Prevention of Preterm Birth

17α hydroxyprogesterone caproate is a synthetic form of the natural progestin 17-α hydroxyprogesterone that is US FDA approved for the prevention of recurrent spontaneous preterm birth in women with a history of a prior singleton preterm birth. For women with a history of a prior spontaneous preterm birth between 20 weeks and 36 weeks and 6 days of gestation, the use of 17-α hydroxyprogesterone caproate has been shown to reduce the risk of recurrent preterm birth by more than 30%. This medication is the only drug currently FDA approved for the prevention of preterm birth, and it is the first drug the FDA has approved for use exclusively during pregnancy in approximately 15 years.