Prior Spontaneous Preterm Delivery Research Articles

Outcomes of history indicated cerclage compared with cervical length screening in patients with cervical insufficiency

To evaluate pregnancy outcomes of history-indicated cerclage compared with ultrasound cervical length screening in patients with a history of cervical insufficiency defined as prior spontaneous preterm delivery from 14 0/7 to 23 6/7 weeks’ of gestation. This was a retrospective cohort study of patients with singleton gestations with a history of cervical insufficiency. We excluded patients who started prenatal care after 24 weeks, who delivered before 24 weeks, and who declined both a history-indicated cerclage or cervical length screening. The primary outcome was preterm delivery < 37 weeks’ gestation. Secondary outcomes included gestational age at delivery, spontaneous preterm birth < 37 weeks, spontaneous preterm birth < 34 weeks, preterm premature rupture of membranes, cesarean delivery, birthweight, and neonatal intensive care (NICU) admissions. Adjusted odds ratios (aOR) with 95th confidence intervals (95%CI) were calculated, controlling for confounders. Of 376 singleton gestations included, 177 (47.1%) underwent history-indicated cerclage and 199 (52.9%) underwent cervical length screening. Of 199 who underwent cervical length screening, 92 (46%) underwent ultrasound-indicated or physical exam-indicated cerclage. Compared to cervical length screening, history-indicated cerclage was not associated with increased odds of preterm delivery less than 37 weeks (37.7% vs. 29.4%; aOR 0.75 [95%CI 0.48-1.18]). However, compared to cervical length screening, history-indicated cerclage was associated with decreased odds of spontaneous preterm delivery less than 34 weeks (18.1% vs. 9.0%; aOR 0.47 [95%CI 0.23-0.97]). History-indicated cerclage compared with cervical length screening was associated with decreased odds of spontaneous preterm delivery less than 34 weeks. Given that approximately half of the patients undergoing cervical length screening required cerclage, history-indicated cerclage should be considered for patients with a history of cervical insufficiency.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

VP46.16: Second trimester cervical length and maternal characteristics in predicting preterm delivery among singleton pregnancies in a Filipino population

This study aimed to identify second trimester cervical length measurements and maternal characteristics associated with preterm delivery among singleton pregnant Filipino women, to generate a model for the prediction of preterm delivery, and to determine its accuracy. This is a retrospective cohort study of Filipino pregnant patients with singleton pregnancies who underwent cervical length evaluation between 16–27 6/7 weeks AOG by transvaginal ultrasound at The Medical City Women's Healthcare Center and delivered in the same institution between 2015 to 2019. Maternal characteristics and CL measurements were obtained from medical records. Univariate analysis using chi-square test for the predictors was initially done. A receiver operating characteristic curve was obtained to determine the area under the curve and the cut-off values of the variables under investigation with the highest sensitivity and specificity. A p value of < 0.05 was considered statistically significant. A risk scoring index was developed for preterm birth using the beta coefficients/odds ratios of the significant clinical predictor variables derived from the logistic regression model. Age > 34 years (OR 1.82, 95% CI 1.04-3.20), prior spontaneous delivery < 37 weeks (OR 2.90, 95% CI 1.07-7.92), and short CL (OR 5.6, 95% CI 2.52-12.57) were associated with preterm delivery, with specificity of 83.5%, sensitivity 50%, NPV 95.7%, PPV 18.5%, and AUC = 0.571. Combined screening using cervical length, age, and prior spontaneous delivery shows a modest increase in sensitivity to 52.6%, and negative predictive value to 97.4%. Although the specificity was only 82.73% and the positive predictive value remained low at 12.3%, the combined model yielded an AUC = 0.677 compared to AUC = 0.571 when cervical length was used alone. Second trimester cervical length combined with age and prior spontaneous preterm delivery has the potential to predict preterm delivery in the current pregnancy.

Obstetrical and neonatal outcomes after a single episode of third-trimester vaginal bleeding†

Objective: The objective of this study is to determine whether a single episode of vaginal bleeding occurring between 24 and 34 weeks gestation is associated with preterm delivery and other adverse maternal and neonatal outcomes. Study design: We conducted a retrospective cohort study in the Maternal–Fetal unit of two campuses of a large tertiary, medical center with approximately 12,000 deliveries annually. The study group consisted of all women with a singleton pregnancy between 24 + 0/7 and 33 + 6/7 weeks of gestation, admitted to the high-risk antenatal ward due to a single episode of vaginal bleeding of unknown origin between May 2003 and December 2014. Maternal and neonatal parameters of the study group were compared to the maternal and neonatal parameters of the rest of the singleton deliveries occurring in our institution during the study period. The primary outcome was rate of preterm delivery while secondary outcomes were other adverse maternal and neonatal outcomes. Multivariate logistic regression was performed to identify risk factors for preterm delivery in the study group. Results: Two hundred thirty women met the inclusion criteria and 51,468 women were in the comparison group. Preterm delivery rates were 20% and 5.5% in the study and the comparison group, respectively OR = 3.55 [2.63–4.78] (p < .001). The aOR for preterm delivery among the study group for women with a previous preterm delivery was 4.62 [1.17–18.20] (p = .029) and for women with a short cervix was 9.35 [2.30–37.95] (p = .002). Conclusions: A single episode of third-trimester vaginal bleeding is an independent risk factor for spontaneous preterm delivery. The presence of a shortened cervix or a history of a prior spontaneous preterm delivery increases this risk significantly. Key message Third trimester vaginal bleeding is strongly associated with preterm delivery. Knowledge of this relationship has valuable clinical implications for practicing obstetricians.

Cross-sectional study of associations between prior spontaneous abortions and preterm delivery.

To evaluate associations between a history of spontaneous abortion and preterm delivery during subsequent pregnancies. The present secondary analysis included cross-sectional survey data related to all deliveries at 103 hospitals in Tehran, Iran, between July 6 and 21, 2015. Trained midwives interviewed patients within 24hours of delivery. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to investigate associations between spontaneous abortion and preterm delivery. Data were included from 4991 deliveries. A history of spontaneous abortion (OR 1.50, 95% CI 1.21-1.87; P=0.001) and history of recurrent spontaneous abortion (OR 3.74, 95% CI 1.90-7.37; P=0.001) were associated with increased odds of preterm delivery in comparison with no such history. Similarly, one (OR 1.33, 95% CI 1.04-1.70; P=0.023), two (OR 1.78, 95% CI 1.15-2.74; P=0.009), or at least three prior spontaneous abortions (OR 4.10, 95% CI 2.08-8.08; P=0.001) were associated with increased odds of preterm delivery compared with none. Population attributable fractions of 9.49% (95% CI 3.36-15.12) and 2.00% (95% CI 0.57-3.56) were calculated for histories of spontaneous abortion and recurrent pregnancy loss, respectively. History of spontaneous abortion and history of recurrent pregnancy loss were associated with increased odds of preterm delivery. A greater number of spontaneous abortions corresponded to greater odds of preterm delivery.

Recurrent Preterm Delivery in Women Receiving 17-P is Not Influenced by Prior Spontaneous Preterm Delivery Etiology [8Q]

INTRODUCTION: To compare rates of recurrent preterm delivery (PTD) in women receiving 17-P therapy for prior spontaneous PTD (sPTD) due to either Preterm Premature Rupture of Membranes (PPROM) or preterm labor (PTL). METHODS: Study sample derived from a national database of women receiving 17-P therapy as part of a PTD prevention program. Inclusion criteria: women meeting SMFM criteria recommendations for 17-P administration, documented history of prior sPTD, singleton gestation and receiving at least 4 weekly 17-P injections. Demographic and clinical risk factors for PTD as well as pregnancy outcomes were compared between those with prior history of sPTD with PTL vs PPROM. Rank and chi-square tests were used to compare study groups, with P-values &lt; .05 considered statistically significant. RESULTS: 2,084 women with prior sPTD were studied: 450 with prior PPROM, 1,634 with prior PTL. There were no significant differences between prior PPROM vs prior PTL study groups for race, ethnicity and pre-pregnancy BMI &lt; 20 or &gt;30. The number of previous PTDs (1.3 ± 0.6 vs 1.3 ± 0.6), gestational age of the most recent PTD (31.8 ± 4.6 vs 31.5 ± 4.5 weeks) and the total number of 17-P injections (18.7 ± 2.4 versus 18.9 ± 2.3) were also similar. Overall, with 17-P therapy, there were no significant differences between study groups for PTD at &lt; 37.0, &lt; 35.0 and &lt; 32.0 weeks or sPTD &lt; 37.0 weeks. CONCLUSION: In women receiving 17-P therapy, recurrent PTD and sPTD rates are not affected by the etiology of the prior sPTD.

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.

Transvaginal Sonographic Evaluation of the Cervix in Asymptomatic Singleton Pregnancy and Management Options in Short Cervix

Preterm delivery (PTD), defined as birth before 37 completed weeks of gestation, is the leading cause of perinatal morbidity and mortality. Evaluation of the cervical morphology and biometry with transvaginal ultrasonography at 16–24 weeks of gestation is a useful tool to predict the risk of preterm birth in low- and high-risk singleton pregnancies. For instance, a sonographic cervical length (CL) > 30 mm and present cervical gland area have a 96-97% negative predictive value for preterm delivery at <37 weeks. Available evidence supports the use of progesterone to women with cervical length ≤25 mm, irrespective of other risk factors. In women with prior spontaneous PTD with asymptomatic cervical shortening (CL ≤ 25 mm), prophylactic cerclage procedure must be performed and weekly to every two weeks follow-up is essential. This article reviews the evidence in support of the clinical introduction of transvaginal sonography for both the prediction and management of spontaneous preterm labour.

567: Comparing the sensitivity of the Hadlock and Williams growth curves in predicting perinatal morbidity and mortality

growth curves in predicting perinatal morbidity and mortality Jonathan M. Snowden, Amy E. Doss, Aaron B. Caughey, Yvonne W. Cheng Oregon Health and Science University, Department of Obstetrics & Gynecology, Portland, OR, Oregon Health & Science University, Department of Obstertics and Gynecology, Portland, OR, University of California, San Francisco, Obstetrics & Gynecology, San Francisco, CA OBJECTIVE: To compare two commonly applied fetal growth curves, Hadlock and Williams, with regards to their sensitivity in identifying small for gestational age (SGA) births that are at elevated risk of adverse perinatal outcomes. STUDY DESIGN: This was a population-based retrospective cohort study of births in the US in 2005, as recorded in the National Center for Health Statistics natality database. We categorized all singleton births as SGA ( 10th percentile of birthweight at a given gestational age) or non-SGA according to two fetal growth curves: the Hadlock and the Williams curves. We fit multivariable logistic regressions to analyze the impact of SGA on several fetal and neonatal outcomes: intrauterine fetal demise (IUFD), infant death, and neonatal intensive care unit (NICU) admission, controlling for confounders including parity, advanced maternal age, and race. RESULTS: Of the 3,705,893 singleton deliveries (births and IUFDs), all 238,799 deliveries categorized as SGA by Williams were also categorized thusly by Hadlock (6.4%). An additional 160,181 (4.3%) were categorized as SGA by Hadlock but not by Williams. The regression analysis demonstrated that births considered SGA by both Hadlock and Williams had significantly elevated odds for all perinatal outcomes analyzed, with adjusted odds ratios (aORs) ranging from 3.66 (95% Confidence Interval: 3.55 3.77) for NICU admission to 8.35 (7.81 8.93) for IUFD. The models also demonstrated that the births identified as SGA by only Hadlock also had significantly increased odds of adverse perinatal outcomes, but with an attenuated magnitude. CONCLUSION: The SGA cutoffs from both the Hadlock and the Williams growth curves identified deliveries with increased odds of IUFD, infant death, and NICU admission. While the more restrictive Williams cutoffs identified births at highly elevated risk, the deliveries identified as SGA by only Hadlock were also at increased risk for these adverse outcomes. Clinicians should be aware that even within a binary category (e.g. SGA and non-), there exists a gradient of risk. 568 Risk factors for spontaneous preterm birth in African-American and Caucasian women receiving 17 -hydroxyprogesterone caproate Julia Timofeev, Jasbir Singh, Niki Istwan, Debbie Rhea, Rita Driggers Washington Hospital Center, Obstetrics and Gynecology, Washington, DC, Alere Health, Department of Clinical Research, Atlanta, GA OBJECTIVE: To determine risk factors for recurrent preterm birth in African-American and Caucasian women receiving 17 -hydroxyprogesterone (17P). STUDY DESIGN: Retrospective analysis of a cohort of women with prior spontaneous preterm delivery (SPTD) enrolled in an outpatient 17P administration program at 27 weeks’ gestation. Maternal characteristics, obstetric history and rates of recurrent SPTD were determined in women of African-American and Caucasian descent using 2 and multivariable logistic regression at two-tailed 0.05. Primary study outcome was the rate of recurrent SPTD 34 weeks. RESULTS: There were 1,913 African-American and 5,195 Caucasian women meeting the inclusion criteria. The overall rate of recurrent SPTD was 28.3%. Rates of recurrent SPTD 37 and 34 weeks were similar among women starting 17P at 16-20.9 vs. 21-26.9 weeks. Table 1 describes maternal characteristics and current pregnancy outcomes. Significant risk factors associated with SPTD 34 weeks in multivariable analysis are presented in Table 2. CONCLUSION: Cervical length 25mm before 27 weeks had the strongest association with SPTD 34 weeks within each maternal race. One or more prior term deliveries attenuated the risk for recurrent SPTD in African-American but not Caucasian women, while tobacco abuse increased the risk for recurrent SPTD in African-American but not Caucasian women. Delineation of race-specific risk factors associated with SPTD can facilitate counseling of women receiving 17P. PosterSessionIV Epidemiology, Infectious Disease, Intrapartum Fetal Assessment, Operative Obstetrics, Obstetric Quality & Safety, Public Health-Global Health www.AJOG.org

Randomized clinical trial of metronidazole plus erythromycin to prevent spontaneous preterm delivery in fetal fibronectin–positive women

Objective To estimate whether antibiotic treatment of asymptomatic women with a positive cervical or vaginal fetal fibronectin test in the second trimester would reduce the risk of spontaneous preterm delivery. Methods Women were screened between 21 weeks 0 days and 25 weeks 6 days of gestation with cervical or vaginal swabs for fetal fibronectin. Women with a positive test (50 ng/mL or more) were randomized to receive metronidazole (250 mg orally three times per day) and erythromycin (250 mg orally four times per day) or identical placebo pills for 10 days. The primary outcome was spontaneous delivery before 37 weeks’ gestation after preterm labor or premature membrane rupture. Results A total of 16,317 women were screened for fetal fibronectin, and 6.6% had a positive test; 715 fetal fibronectin test–positive women consented to randomization. Outcome data were available for 703 women: 347 in the antibiotic group and 356 in the placebo group. The antibiotic and placebo groups were not significantly different for maternal age ( P = .051), ethnicity ( P = .849), marital status ( P = .127), education ( P = .244), and bacterial vaginosis ( P = .236). No difference was observed in spontaneous preterm birth before 37 weeks’ (odds ratio [OR] 1.17, 95% confidence interval [CI] 0.80, 1.70), less than 35 weeks’ (OR 0.92, 95% CI 0.54, 1.56), or less than 32 weeks’ (OR 1.94, 95% CI 0.83, 4.52) gestation in antibiotic- compared with placebo-treated women. Among women with a prior spontaneous preterm delivery, the rate of repeat spontaneous preterm delivery at less than 37 weeks’ gestation was significantly higher in the active drug compared with the placebo group (46.7% versus 23.9%, P = .039). Conclusion Treatment with metronidazole plus erythromycin of asymptomatic women with a positive cervical or vaginal fetal fibronectin test in the late second trimester does not decrease the incidence of spontaneous preterm delivery.

The Preterm Prediction Study: Effect of gestational age and cause of preterm birth on subsequent obstetric outcome

Objective: We sought to evaluate the association between prior spontaneous preterm delivery and subsequent pregnancy outcome. Study Design: A total of 1711 multiparous women with singleton gestations were prospectively evaluated at 23 to 24 weeks’ gestation. Prior pregnancies were coded for the presence or absence of a prior spontaneous preterm delivery. If a prior spontaneous preterm delivery had occurred, the gestation of the earliest prior delivery (13-22, 23-27, 28-34, and 35-36 weeks’ gestation) was recorded. Current gestations were categorized as spontaneous preterm delivery at <28, <30, <32, <35, or <37 weeks’ gestation. The risk of spontaneous preterm delivery in the current gestation was determined on the basis of the occurrence, gestational age, and cause of the earliest prior spontaneous preterm delivery. Results: The incidences of spontaneous preterm delivery before 28, 30, 32, 35, and 37 weeks’ gestation were 0.8%, 1.1%, 1.9%, 5.1%, and 11.9%, respectively. Those with a prior spontaneous preterm delivery carried a 2.5-fold increase in the risk of spontaneous preterm delivery in the current gestation over those with no prior spontaneous preterm delivery (21.7% vs 8.8%; P ≤ .001). Gravid women with an early prior spontaneous preterm delivery (23-27 weeks’ gestation) had a higher risk of recurrent spontaneous preterm delivery (27.1% vs 8.8%; P ≤ .001). Prior spontaneous preterm delivery was more closely associated with subsequent early spontaneous preterm delivery at <28 weeks’ gestation (relative risk, 10.6) than for spontaneous preterm delivery overall (relative risk, 2.5). An early prior spontaneous preterm delivery (23-27 weeks’ gestation) was most highly associated with early spontaneous preterm delivery (<28 weeks’ gestation) in the current gestation (relative risk, 22.1). The relationship between prior spontaneous preterm delivery and current outcome was not as strong for those with a very early spontaneous preterm delivery (13-22 weeks’ gestation). Prior spontaneous preterm delivery caused by preterm premature rupture of the membranes and preterm labor was significantly associated with similar outcomes in the current gestation ( P < .001). Conclusion: Prior spontaneous preterm delivery is highly associated with recurrence in the current gestation. An early prior spontaneous preterm delivery is more predictive of recurrence and is most highly associated with subsequent early spontaneous preterm delivery. (Am J Obstet Gynecol 1999;181:1216-21.)

The preterm prediction study: A clinical risk assessment system

OBJECTIVE: Our aims were to develop a risk assessment system for the prediction of spontaneous preterm delivery using clinical information available at 23 to 24 weeks' gestation and to determine the predictive value of such a system. STUDY DESIGN: A total of 2929 women were evaluated between 23 and 24 weeks' gestation at 10 centers. Demographic factors, socioeconomic status, home and work environment, drug and alcohol use, and medical history were evaluated. Information regarding symptoms, cultures, and treatments in the current pregnancy were ascertained. Anthropomorphic and cervical examinations were performed. Univariate analysis and multivariate logistic regression were performed in a random selection, constituting 85% of the study population. The derived risk assessment system was applied to the remaining 15% of the population to evaluate its validity. RESULTS: A total of 10.4% of women were delivered of preterm infants. The multivariate models for spontaneous preterm delivery were highly associated with spontaneous preterm delivery ( p < 0.0001). A low body mass index (<19.8) and increasing Bishop scores were significantly associated with spontaneous preterm delivery in nulliparous and multiparous women. Black race, poor social environment, and work during pregnancy were associated with increased risk for nulliparous women. Prior obstetric outcome overshadowed socioeconomic risk factors in multiparous women with a twofold increase in the odds of spontaneous preterm delivery for each prior spontaneous preterm delivery. Current pregnancy symptoms, including vaginal bleeding, symptomatic contractions within 2 weeks, and acute or chronic lung disease were variably associated with spontaneous preterm delivery in nulliparous and multiparous women. When the system was applied to the remainder of the population, women defined to be at high risk for spontaneous preterm delivery ( ≥20% risk) carried a 3.8-fold (nulliparous women) and 3.3-fold (multiparous women) higher risk of spontaneous preterm delivery than those predicted to be at low risk. However, the risk assessment system identified a minority of women who had spontaneous preterm deliveries. The sensitivities were 24.2% and 18.2% and positive predictive values were 28.6% and 33.3%, respectively, for nulliparous and multiparous women. CONCLUSIONS: Although it is possible to develop a graded risk assessment system that includes factors that are highly associated with spontaneous preterm delivery in nulliparous and multiparous women, such a system does not identify most women who subsequently have a spontaneous preterm delivery. This system has investigational value as the basis for evaluating new technologies designed to identify at-risk subpopulations. (Am J Obstet Gynecol 1996;174:1885-95.)