Prior Spontaneous Preterm Birth Research Articles

Cost-effectiveness of risk-based screening for cervical length to prevent preterm birth

Despite much debate, there is no consensus on whether women without a history of prior spontaneous preterm birth should receive universal cervical length screening. Risk-based screening has been proposed as an alternative to universal cervical length measurement and may represent a more cost-effective approach to preterm birth prevention. We sought to evaluate the cost-effectiveness of risk-based screening compared to universal cervical length screening or no screening for preterm birth prevention in low-risk women. A decision analytic model compared the cost and effectiveness of 3 cervical length screening strategies in a population of women with no prior preterm birth. Risk-based screening, universal screening, and no screening were compared using cost, probability, and utility estimates derived from the existing literature and the incremental cost-effectiveness ratios for each strategy were calculated. In the base-case analysis, risk-based screening and universal screening were more effective and less costly than no screening. In comparison to the risk-based strategy, universal screening of the United States population of women without a prior preterm birth (N= 3.5 million annually) would result in 2.19 million more transvaginal ultrasounds, 11,027 more women treated with vaginal progesterone, 913 fewer preterm births <35 weeks gestational age, and 63 fewer neonatal deaths at an additional cost of $51,936,699 annually. Despite costing more, the additional health benefits of universal screening resulted in that strategy being more cost-effective than risk-based screening, with an incremental cost-effectiveness ratio of $21,144 per quality-adjusted life-year. In women without a prior spontaneous preterm birth, universal cervical length screening is cost-effective in comparison to both risk-based screening and no screening.

17-Hydroxyprogesterone caproate (17OHP-C) coverage among eligible women delivering at 2 North Carolina hospitals in 2012 and 2013: A retrospective cohort study

Although a weekly injection of 17-hydroxyprogestone caproate is recommended for preventing recurrent preterm birth, clinical experience in North Carolina suggested that many eligible patients were not receiving the intervention. Our study sought to assess how well practices deliveringat 2 major hospitals were doing in providing access to 17-hydroxyprogesterone caproate treatment for eligible patients. This retrospective cohort analysis studied all deliveries occurring between January 1, 2012, and December 31, 2013, at 2 large hospitals in North Carolina. Women were included if they had asingleton pregnancy and history of a prior spontaneous preterm birth. Weextracted demographic, payer, and medical information on each pregnancy, including whether women had been offered, accepted, and received 17-hydroxyprogesterone caproate. Our outcome of 17-hydroxyprogesterone caproate coverage was defined as documentation of ≥1 injection of the drug. Over the 2-year study period, 1216 women with history of a prior preterm birth delivered at the 2 study hospitals, of which 627 were eligible for 17-hydroxyprogesterone caproate eligible after medical record review. Only 296 of the 627 eligible women (47%; 95% confidence interval, 43-51%) received ≥1 dose of the drug. In multivariable analysis, hospital of delivery, later presentation for prenatal care, fewer prenatal visits, later gestation of prior preterm birth, and having had a term delivery immediately before the index pregnancy were all associated with failed coverage. Among those women who were "covered," the median number of 17-hydroxyprogesterone caproate injections was 9 (interquartile range, 4-15), with 84 of 296 charts (28%) not having complete information on the number of doses. Even under our liberal definition of coverage, less than half of eligible women received 17-hydroxyprogesterone caproate in this sample. Low overall use suggests that there is opportunity for improvement. Quality improvement strategies, including population-based measurement of 17-hydroxyprogesterone caproate coverage, are needed to fully implement this evidence-based intervention to decrease preterm birth.

Optimizing Subsequent Pregnancy Outcomes for Women with a Prior Preterm Birth.

Women with a prior preterm birth are at increased risk of recurrent preterm delivery in a subsequent pregnancy. Interventions during the preconception and prenatal periods can decrease this risk. Review of the circumstances of the prior delivery can elucidate whether delivery was spontaneous or indicated, anticipate recurrence risk, and guide management in a subsequent pregnancy. Preconception interventions for women with prior preterm birth should include cessation of tobacco and substance abuse, control of underlying maternal comorbidities, and encouraging a healthy body mass index. Effective contraception, including use of long-acting reversible methods, should be encouraged to facilitate planned pregnancies with optimal interpregnancy intervals. Interventions during prenatal care include screening and treatment of infections, nutritional supplementation, and enhanced prenatal care. Women with prior spontaneous preterm birth may benefit from progesterone supplementation and serial cervical length screening, while women with prior indicated preterm birth may benefit from daily aspirin.

Clinical Application of Progesterone for the Prevention of Preterm Birth, 2016.

While the preterm neonate continues to benefit from improved perinatal care, the rate of preterm birth in the United States remains significant. An increasing body of scientific literature has demonstrated the benefits of maternal progesterone administration in reducing primary and recurrent preterm birth. Intramuscular hydroxyprogesterone caproate is indicated in singleton pregnancies in women with a prior spontaneous preterm birth, while vaginal progesterone demonstrates similar efficacy in prolonging pregnancy in women with asymptomatic cervical shortening in the midtrimester. Given these favorable benefits, the use of progesterone has been expanded to other clinical situations at risk for preterm birth with less rigorous scientific evidence. This review highlights the current evidence-based clinical applications of progesterone for prevention of preterm birth.

Activity in Pregnancy for Patients with a History of Preterm Birth.

Preterm birth remains a leading cause of neonatal morbidity and mortality throughout the world. Numerous risk factors for preterm birth have been identified, including non-Hispanic black race, a variety of social and behavioral factors, infections, and history of a prior preterm delivery. Of these, a history of prior spontaneous preterm birth is one of the strongest risk factors. Traditionally, women with a history of preterm birth or those deemed at high risk for preterm delivery have been placed on bed rest or a reduced activity regimen during their pregnancy. However, there is little evidence to support this recommendation. Recent research has suggested that regular physical activity and exercise during pregnancy is safe and does not increase the risk of preterm delivery. Therefore, physicians should encourage women with a history of preterm birth to exercise throughout pregnancy according to guidelines published by the American College of Obstetricians and Gynecologists as long as they are receiving regular prenatal care and their current health status permits exercise. However, there are no randomized controlled trials evaluating exercise prescription in women with a history of preterm birth, hence additional research is needed in this area.

544: The relationship between body mass index, cervical length and spontaneous preterm birth

There is conflicting evidence about the association of maternal weight with spontaneous preterm birth (SPTB), with some studies suggesting that SPTB decreases as maternal body mass index (BMI) increases and other suggesting that it increases with BMI. The objective of this study was to determine if mid-trimester cervical length (CL) mediates the relationship between BMI and SPTB. This was a retrospective cohort of women with a singleton pregnancy who underwent routine transvaginal CL assessment between 18 and 24 weeks. Women were categorized into the IOM-defined BMI categories based on BMI at the time of delivery (normal, overweight, class 1 obesity, class 2 obesity or higher). Women with prior SPTB or stillbirth in current pregnancy were excluded. Univariable comparisons of maternal characteristics (including mid-trimester CL) and BMI categories were conducted with Chi square or one way ANOVA tests followed by Scheffe multiple comparisons. The rate of SPTB was then compared across BMI categories. Multivariable logistic regression was done to determine whether BMI category was associated with SPTB independent of the CL. Of the 18,100 women included in this analysis, 2403 (13.3%) were normal weight, 7822 (43.2%) were overweight, 2962 (16.4%) were class 1 obesity, and 4913 (27.1%) were class 2 obesity or higher. In univariable analysis, increasing BMI category was associated with longer CL (4.4cm ± 0.8, 4.5cm ± 0.8, 4.5cm ± 0.8 and 4.6cm ± 0.9, p<.001). SPTB was less common among women with increasing BMI category (5.6%, 3.9%, 4.2% and 3.7%, p=.002). In multivariable regression, a higher BMI category was associated with a lower frequency of SPTB. This association persisted when CL was entered into the model as a covariate (Table). Despite all the adverse outcomes associated with high BMI and pregnancy, women with a higher BMI category had longer mid-trimester CL and, correspondingly reduced SPTB. However, the decreased risk of SPTB was not completely mediated by having a longer cervical length. The reason for the potential protective effect from prematurity is unknown and its mechanisms require further investigation.

Prior Ultrasound-Indicated Cerclage

To evaluate outcomes of women with prior ultrasound-indicated cerclage, who in their subsequent pregnancy were either followed by transvaginal ultrasound cervical length screening or received a planned history-indicated cerclage. Multicenter cohort study of singleton gestations with a prior ultrasound-indicated cerclage performed from 1994 to 2014. We evaluated three pregnancies in the study participants: first pregnancy with prior spontaneous preterm birth at less than 37 weeks of gestation; second pregnancy with ultrasound-indicated cerclage for cervical length 25 mm or less; and the third index pregnancy managed with either transvaginal ultrasound cervical length screening with ultrasound-indicated cerclage for cervical length 25 mm or less or planned history-indicated cerclage. The primary outcome was incidence of spontaneous preterm birth at less than 37 weeks of gestation. We planned a subgroup analysis for women who delivered at less than 32 weeks of gestation compared with 32 weeks of gestation or greater in their prior ultrasound-indicated cerclage pregnancy. Of 102 singleton gestations included, 38 (37.3%) were followed with transvaginal ultrasound cervical length screening and 64 (62.7%) underwent history-indicated cerclage. Of 38 women in the transvaginal ultrasound group, 18 (47.4%) underwent ultrasound-indicated cerclage for cervical length 25 mm or less. After adjusting for confounders, the rate of spontaneous preterm birth at less than 37 weeks of gestation was similar between transvaginal ultrasound cervical length screening and history-indicated cerclage groups (36.8% compared with 43.8%; adjusted odds ratio 0.77, 95% confidence interval 0.47-1.45). Secondary outcomes were also similar in both groups. All women (n=7) who delivered at less than 32 weeks of gestation in their prior pregnancy and subsequently had transvaginal ultrasound screening received ultrasound-indicated cerclage in the index pregnancy compared with only 35.5% of women who delivered at 32 weeks of gestation or greater in their prior pregnancy. Women with prior ultrasound-indicated cerclage have similar outcomes if they receive either transvaginal ultrasound cervical length screening with ultrasound-indicated cerclage for cervical length 25 mm or less or planned history-indicated cerclage in the subsequent pregnancy. Less than 50% of the transvaginal ultrasound cervical length screening group require a repeat ultrasound-indicated cerclage in the subsequent pregnancy. II.

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.

Cost-effectiveness of transvaginal ultrasound cervical length screening in singletons without a prior preterm birth: an update

We sought to reevaluate the cost-effectiveness of universal transvaginal ultrasound (TVU) cervical length (CL) screening in singleton pregnancies without prior spontaneous preterm birth. We developed a decision model to assess costs and effects of universal TVU CL screening at 18-23 weeks' gestation compared to routine care for singleton pregnancies without prior preterm birth. Based on recent data, the model contains the following updates: (1) reduced incidence of CL ≤20 mm at initial screening ultrasound (0.83%), (2) vaginal progesterone supplementation for women with CL ≤20 mm, (3) additional ultrasound(s) for women with CL 21-24.9 mm, and (4) the assumption that vaginal progesterone reduces the rate of preterm birth <34 weeks' gestation by 39% if a short CL is diagnosed. The primary outcome was incremental cost-effectiveness ratio. We assumed a willingness to pay of $100,000 per quality-adjusted life year (QALY) gained. Additional outcomes included incidence of offspring with long-term neurological deficits and neonatal death. Sensitivity analyses were performed to assess the robustness of the results. For every 100,000 women screened, universal TVU CL screening costs $9132 compared to routine care. Screening results in 215 QALYs gained and 10 fewer neonatal deaths or neonates with long-term neurologic deficits per 100,000 women screened. Based on the updated data, universal CL screening in low-risk women remains a cost-effective strategy (incremental cost-effectiveness ratio = $43/QALY), but is not cost saving as previously estimated. Sensitivity analyses reveal that when incidence of TVU CL ≤20 mm is <0.31%, universal TVU CL screening is no longer cost-effective. Additionally, when TVU CL costs >$314, progesterone reduces preterm delivery risk before 34 weeks <19%, or the incidence of a TVU CL 21-24.9 mm is >6.5%, CL screening is also no longer cost-effective. Despite the reduced incidence and efficacy used in this model, universal TVU CL continues to be cost-effective when compared to routine care in singletons without prior preterm birth.

Relationship between interpregnancy interval and cervical length in high-risk women

Objective: Our objective was to evaluate the relationship between the interpregnancy interval (IPI) and next-pregnancy mid-trimester cervical length (CL) in women at high risk for recurrent spontaneous preterm birth (SPTB).Methods: Retrospective review identified high-risk women, defined as a prior SPTB <36 weeks, who began scheduled serial transvaginal sonographic CL screening at 16–18 weeks gestation between December 2008 and November 2010. All CL assessment ended by 226/7 weeks, and weekly 17-α hydroxyprogesterone caproate, 250 mg IM, was recommended to all patients. Details of the prior and current pregnancy were collected, and regression models were used to evaluate the relationship between IPI and CL shortening.Results: One hundred and eight women with singleton gestations and a qualifying SPTB underwent CL screening. The mean (SD) birth gestational age (GA) of the last pregnancy was 25 (10) weeks, the median IPI was 613 (range 49–6038) days, and the mean (SD) delivery GA in the current pregnancy was 36 (5.3) weeks. Linear regression found no significant relationship between the IPI and the GA of the current birth (p = 0.98). There was a weak significant relationship between IPI and shortest CL (p = 0.04). However, after controlling for the GA of the prior pregnancy, this relationship was non-significant (p = 0.13).Conclusions: IPI does not predict next birth outcome or next-pregnancy mid-trimester CL in high-risk women managed with progesterone and ultrasound-indicated cerclage.

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.

560: Predictors of response to 17-alpha hydroxyprogesterone caproate (17P) for prevention of recurrent spontaneous preterm birth (SPTB)

We hypothesized that differences in demographics, history, and pregnancy course affect response to 17P for recurrent SPTB prevention. Secondary analysis of a prospective, multi-center, longitudinal study of women with >1 prior SPTB <37 weeks gestation. Data were collected at 3 pre-specified gestational age epochs during pregnancy. All women included in this analysis received 17P during the studied pregnancy. We classified women as a 17P responder or non-responder by calculating the difference in delivery gestational age between the 17P treated pregnancy and her earliest SPTB. Responders delivered at term and/or ≥3 weeks later with 17P vs. their earliest SPTB. 11 women whose earliest SPTB was late preterm and delivered <3 weeks later but at term were considered ‘equivocal’ responders and were excluded. Data were analyzed using chi2, t-test, and logistic regression. 155 women met inclusion criteria. The 118 responders delivered later on average (37.7 weeks) than the 37 non-responders (33.5 weeks), p<0.001. Although 32% of responders (38/118) had a recurrent SPTB, they were considered responders because they delivered ≥3 weeks later compared to their earliest SPTB. Demographics (age, race/ethnicity, education, and parity) were similar between groups. Selected historical and current pregnancy factors are shown in the Table.In the regression model, each additional week gestation of the earliest prior SPTB (OR 0.68, 95% CI 0.56-0.82, p<0.001), vaginal bleeding/abruption in the current pregnancy (OR 0.24, 95% CI 0.06-0.88, p=0.031), and first-degree family history of SPTB (OR 0.37, 95% CI 0.15-0.88, p=0.024) were associated with reduced likelihood of response to 17P. Several historical and current pregnancy characteristics define women at risk for suboptimal response to 17P. These data should be prospectively studied in larger cohorts and combined with genetic and environmental data to identify women most likely to benefit from this intervention.

101: Cervicovaginal fluid proteomic analysis identifies multiple potential biomarkers for preterm birth

Prior to spontaneous preterm birth (SPTB) genital tract tissues likely produce secretions that could be measured in cervicovaginal fluid (CVF) and serve as markers for SPTB. We utilized quantitative proteomics to identify potential CVF biomarkers for SPTB in asymptomatic, pregnant women with a prior SPTB.

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.

A universal transvaginal cervical length screening program for preterm birth prevention.

To evaluate a universal transvaginal ultrasonogram cervical length screening program on the incidence of a cervical length 20 mm or less and adherence to the management protocol for a cervical length less than 25 mm. We conducted a prospective cohort study of women with singleton gestations 18 0/7 to 23 6/7 weeks of gestation eligible for universal transvaginal ultrasonogram cervical length screening over an 18-month period. Only women receiving antenatal care at our institution were included. Women with a prior spontaneous preterm birth and without delivery data available were excluded. A transvaginal ultrasonogram cervical length of less than 25 mm was managed according to a predetermined protocol. Primary outcomes were the incidence of a cervical length 20 mm or less and adherence to the management protocol for a cervical length less than 25 mm. Secondary outcomes were the incidences of spontaneous preterm birth at less than 37, less than 34, or less than 32 weeks of gestation among women undergoing transvaginal ultrasonogram cervical length screening compared with those not screened. One thousand five hundred sixty-nine of 2,171 (72.3%) eligible women underwent transvaginal ultrasonogram cervical length screening. Overall, 17 (1.1%, 95% confidence interval [CI] 0.66-1.74) women had a cervical length 20 mm or less before 24 weeks of gestation. Management protocol deviations occurred in nine women with a cervical length less than 25 mm (43%, 95% CI 24.3-63.5). There was no difference in the incidence of spontaneous preterm birth at less than 37 weeks of gestation (4.1 compared with 4.7%, adjusted odds ratio [OR] 0.91, 95% CI 0.57-1.45), less than 34 weeks of gestation (1.5 compared with 1.3%, adjusted OR 1.19, 95% CI 0.52-2.74), or less than 32 weeks of gestation (0.8 compared with 0.8%, adjusted OR 0.0.76, 95% CI 0.26-2.25) among women receiving transvaginal ultrasonogram cervical length screening compared with those not screened. In a universal transvaginal ultrasonogram cervical length screening program, the incidence of a cervical length 20 mm or less was 1.1% in women with singleton gestations without prior spontaneous preterm birth. Protocol deviations occurred in 43% of women with a cervical length less than 25 mm. The incidence of spontaneous preterm birth was similar among women undergoing transvaginal cervical length screening compared with those not screened. LEVEL OF EVIEDENCE: II.

Cervical cerclage.

Cervical cerclage is an obstetric procedure performed for prevention of prematurity. Cerclage was first introduced by Drs Shirodkar and McDonald in the mid-1950s for women with repeated second trimester losses and cervical changes in current pregnancy. Currently, cerclage placement is based on 3 common indications in singleton gestations, including history-indicated (prior multiple early preterm births or second trimester losses), ultrasound-indicated (cervical length <25 mm before 24-wk gestational age in women with prior spontaneous preterm birth) and physical examination-indicated (cervical dilation on manual or physical examination before 24 wk).

Effectiveness of progestogens to improve perinatal outcome in twin pregnancies: an individual participant data meta-analysis.

In twin pregnancies, the rates of adverse perinatal outcome and subsequent long-term morbidity are substantial, and mainly result from preterm birth (PTB). To assess the effectiveness of progestogen treatment in the prevention of neonatal morbidity or PTB in twin pregnancies using individual participant data meta-analysis (IPDMA). We searched international scientific databases, trial registration websites, and references of identified articles. Randomised clinical trials (RCTs) of 17-hydroxyprogesterone caproate (17Pc) or vaginally administered natural progesterone, compared with placebo or no treatment. Investigators of identified RCTs were asked to share their IPD. The primary outcome was a composite of perinatal mortality and severe neonatal morbidity. Prespecified subgroup analyses were performed for chorionicity, cervical length, and prior spontaneous PTB. Thirteen trials included 3768 women and their 7536 babies. Neither 17Pc nor vaginal progesterone reduced the incidence of adverse perinatal outcome (17Pc relative risk, RR 1.1; 95% confidence interval, 95% CI 0.97-1.4, vaginal progesterone RR 0.97; 95% CI 0.77-1.2). In a subgroup of women with a cervical length of ≤25 mm, vaginal progesterone reduced adverse perinatal outcome when cervical length was measured at randomisation (15/56 versus 22/60; RR 0.57; 95% CI 0.47-0.70) or before 24 weeks of gestation (14/52 versus 21/56; RR 0.56; 95% CI 0.42-0.75). In unselected women with an uncomplicated twin gestation, treatment with progestogens (intramuscular 17Pc or vaginal natural progesterone) does not improve perinatal outcome. Vaginal progesterone may be effective in the reduction of adverse perinatal outcome in women with a cervical length of ≤25 mm; however, further research is warranted to confirm this finding.

Relationship Between Interpregnancy Interval and Cervical Length in High-Risk Women

AbstractObjective: Our objective was to evaluate the relationship between the interpregnancy interval (IPI) and next-pregnancy mid-trimester cervical length (CL) in women at high risk for recurrent spontaneous preterm birth (SPTB).Methods: Retrospective review identified high-risk women, defined as a prior SPTB <36 weeks, who began scheduled serial transvaginal sonographic CL screening at 16–18 weeks gestation between December 2008 and November 2010. All CL assessment ended by 226/7 weeks, and weekly 17-α hydroxyprogesterone caproate, 250 mg IM, was recommended to all patients. Details of the prior and current pregnancy were collected, and regression models were used to evaluate the relationship between IPI and CL shortening.Results: One hundred and eight women with singleton gestations and a qualifying SPTB underwent CL screening. The mean (SD) birth gestational age (GA) of the last pregnancy was 25 (10) weeks, the median IPI was 613 (range 49–6038) days, and the mean (SD) delivery GA in the current preg...

Does Second-Trimester Cervical Length Predict Prolonged Pregnancy?

INTRODUCTION: Third-trimester cervical length has been correlated with delivery timing. Given that second-trimester ultrasonography is routine practice, we sought to evaluate whether second-trimester cervical length is associated with prolonged pregnancy. METHODS: We performed a secondary analysis of data involving women with singleton gestations between 18 0/7 and 23 6/7 weeks of gestation undergoing universal transvaginal ultrasound cervical length screening for preterm birth prediction from January 1, 2012, to December 30, 2012. Women with prior spontaneous preterm births, cerclage in situ, and deliveries at outside institutions were excluded. Women were included if they had spontaneous labor, rupture of membranes, or reached 41 weeks of gestation. The primary outcome was the incidence of prolonged pregnancy (41 0/7 weeks of gestation and beyond). A receiver operating characteristic curve was calculated to identify the threshold cervical length predictive of a prolonged pregnancy. Statistical analysis was performed using SPSS 20.0. RESULTS: Of the 660 women who met inclusion criteria, 108 (16.4%) had prolonged pregnancies. Women with prolonged pregnancies had a higher mean body mass index and were less likely to have had a prior vaginal delivery compared with women without prolonged pregnancies. Women with prolonged pregnancies also had higher mean cervical length (43 compared with 42 mm, P=.057) and a higher incidence of cervical length greater than 30 mm (100% compared with 96%, P=.035; Table 1). The receiver operating characteristic curve demonstrated an area under the curve of 0.542 (standard error 0.027; Figure 1); no optimal cervical length was predictive of a prolonged pregnancy.CONCLUSIONS: Second-trimester cervical length is not predictive of prolonged pregnancy.