Preterm Birth In Singleton Pregnancies Research Articles

P-767 Preterm birth in singleton pregnancies conceived by in-vitro fertilization or intracytoplasmic sperm injection: a systematic review with umbrella meta-analysis

Abstract Study question What is the risk level and potential etiology of preterm birth (PTB) in singleton pregnancies from in-vitro fertilization (IVF) or intra-cytoplasmic injection (ICSI)? Summary answer Singleton pregnancies from IVF/ICSI have, on average, double the risk of PTB compared to natural conceptions, with a higher risk for iatrogenic than spontaneous PTB. What is known already IVF/ICSI pregnancies are associated with a higher PTB risk, with a predominant effect mediated by the effect of multiples and a poor understanding of underlying etiology, particularly in singletons. According to the European IVF Monitoring Consortium (EIM) for the European Society of Human Reproduction and Embryology (ESHRE), about 16% of singleton conceived through IVF/ICSI were born preterm in 2019. Considering the global a shift towards single embryo transfers (ETs), it becomes crucial to precisely determine and convey the PTB risk specific to singleton pregnancies conceived through IVF/ICSI, collecting all available evidence on supposed PTB etiology. Study design, size, duration A comprehensive search in major online databases was conducted up to December 31, 2023. Eligible studies were systematic reviews with quantitative data. The primary aim was to quantify PTB risk in singletons conceived by IVF/ICSI compared to natural pregnancies. Secondary objectives included assessing very preterm birth (VPTB) risk and exploring PTB’s etiology, phenotype, and initiation. PTB and VPTB were defined by the World Health Organization as delivery before 37 or 32 weeks, respectively. Participants/materials, setting, methods Random-effects meta-analysis models were used for pooling effect measures. Estimates were presented as odds ratios (ORs) with 95% confidence intervals (CIs). Information available on etiology, phenotype, initiation of PTB and relevant moderators was extracted and employed for subgroup analyses. The extent of overlap in the original studies was measured using the Corrected Covered Area (CCA) assessment. The quality of the included reviews was evaluated with the AMSTAR 2 tool and quality of evidence by GRADE. Main results and the role of chance Twelve meta-analyses with a total of 16,522,917 pregnancies were included. IVF/ICSI singletons showed a significantly higher risk of PTB compared to natural conception (PTB ˂37 weeks: OR: 1.72, 95% CI: 1.57-1.89). The pooled risk estimate was higher for births below 32 weeks (VPTB <32 weeks: OR: 2.19, 95%CI: 1.82-2.64). Influential analysis reinforced the strength of this association. Subgroup analyses investigating supposed etiology revealed a comparable risk magnitude for spontaneous PTB (OR 1.79, 95% CI:1.56-2.04) and a greater risk for iatrogenic PTB (OR: 2.28, 95%CI: 1.72–3.02). PTB risk was consistent in the subgroup of conventional IVF (OR: 1.95, 95% CI: 1.76-2.15) and higher in the subgroup of fresh-only ETs (OR: 1.79, 95% CI: 1.55-2.07) compared to frozen-thawed ETs (OR: 1.39, 95%CI: 1.34-1.43). CCA assessment showed minimal study overlap (13%). The quality of the evidence by GRADE assessment was judged as low to very low. Limitations, reasons for caution The methodological quality of the included reviews, as rated by AMSTAR 2, was judged as low to very low. Most included studies lacked granular data on IVF/ICSI indications and on specific PTB etiology, phenotypes, or initiation. Wider implications of the findings The risk of PTB is about double in IVF/ICSI singleton pregnancies compared to naturally conceived, with paucity of available data on PTB aetiology, phenotype, or initiation. The greater risk increase involves iatrogenic PTB from fresh ET and VPTB, likely due to placental aetiology. Trial registration number PROSPERO ID: CRD42023411418

Maternal Risk Factors Associated with Preterm Birth: A Case Control Study.

Preterm birth is the child birth before 37 completed weeks .Prematurity is one of the leading causes of neonatal morbidity and mortality due to the complications associated with it. The objective of the study was to determine the maternal risk factors associated with all preterm birth in singleton pregnancy at National hospital. Hospital based unmatched case control study was conducted between March 2021 to December 2021 at National hospital, Thimphu, Bhutan. Case to control ratio was 1:2.Data were collected using interviewer -administered structured questionnaires. The collected data were entered into Epi-data and exported into SPSS for analysis. Independent variables with p-valves<0.05 in the univariate analysis were entered to multi variable logistic model to estimate the strength of association .P-valve <0.05 was considered significant. Total of 107 cases and 201 controls participated with a response rate of 95.95%.Multiple logistic regression showed that mothers with ANC follow ≤ four[aOR 9.58(7.36-28.86) ], previous history of preterm delivery [aOR 2.99(1.5-15.77) ], previous caesarean section [aOR 5.72(2.19-14.92)], prelabour rupture of membrane [aOR 8.67(3.78-19.73)], fetal growth restriction [aOR 7.28(2.11-25.11)] , and pre-eclampsia [aOR 10.99(6.75-85.29) were the risk factors positively associated with preterm birth . This study highlights that preeclampsia, number of antenatal care visits ≤ four, prelabour rupture of membrane, fetal growth restriction, previous caesarean section and previous preterm delivery were the risk factors for preterm birth. This show the need of early screening and prevention of preeclampsia, strengthening of antenatal care follow-up, and treatment of infection to prevent prelabour rupture of membrane, reducing primary caesarean section and more attention and care with previous preterm birth .

Predicting risk of preterm birth in singleton pregnancies using machine learning algorithms.

We aimed to develop, train, and validate machine learning models for predicting preterm birth (<37 weeks' gestation) in singleton pregnancies at different gestational intervals. Models were developed based on complete data from 22,603 singleton pregnancies from a prospective population-based cohort study that was conducted in 51 midwifery clinics and hospitals in Wenzhou City of China between 2014 and 2016. We applied Catboost, Random Forest, Stacked Model, Deep Neural Networks (DNN), and Support Vector Machine (SVM) algorithms, as well as logistic regression, to conduct feature selection and predictive modeling. Feature selection was implemented based on permutation-based feature importance lists derived from the machine learning models including all features, using a balanced training data set. To develop prediction models, the top 10%, 25%, and 50% most important predictive features were selected. Prediction models were developed with the training data set with 5-fold cross-validation for internal validation. Model performance was assessed using area under the receiver operating curve (AUC) values. The CatBoost-based prediction model after 26 weeks' gestation performed best with an AUC value of 0.70 (0.67, 0.73), accuracy of 0.81, sensitivity of 0.47, and specificity of 0.83. Number of antenatal care visits before 24 weeks' gestation, aspartate aminotransferase level at registration, symphysis fundal height, maternal weight, abdominal circumference, and blood pressure emerged as strong predictors after 26 completed weeks. The application of machine learning on pregnancy surveillance data is a promising approach to predict preterm birth and we identified several modifiable antenatal predictors.

Combined effects of pre-pregnancy BMI and gestational weight gain on preterm birth: comparison between spontaneous and ART conception.

Inappropriate pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) are both linked to preterm birth (PTB); however, which one plays a dominant role in PTB risk is not yet sure. We aimed to evaluate the combined effect of pre-pregnancy BMI and GWG on the risk of PTB in singleton pregnancies conceived both spontaneously and through assisted reproductive technology (ART). The data included all mothers (n = 17,540,977) who had a live singleton birth from the US National Vital Statistics System (NVSS) 2015-2019. Logistic regression models, quantile-g-computation, and generalized additive model were used to analyze the combined association of pre-pregnancy BMI and GWG with PTB. The singleton PTB rate was significantly higher in ART pregnancies (11.5%) than in non-ART pregnancies (7.9%). When compared to those women with pre-pregnancy normal weight and GWG within Institute of Medicine (IOM) guidelines, the highest PTB risk was observed in non-ART women with pre-pregnancy underweight and GWG below IOM guidelines (aOR 2.56; 95% CI 2.53-2.60) and in ART women with pre-pregnancy obese and GWG below IOM guidelines (aOR 2.56; 95%CI 2.36-2.78). GWG dominated the combined effect with its joint effect coefficient of - 0.281 (P < 0.05) in non-ART women and - 0.108 (P < 0.05) in ART women. Inappropriate GWG played a dominant role in increasing the risk of PTB in both non-ART and ART populations. Counseling regarding pre-pregnancy BMI and especially GWG appears to be even more crucial for pregnancies conceived via ART, given their impact on PTB.

Cervical elastography in predicting spontaneous preterm birth in singleton pregnancy with a short cervix receiving progesterone treatment at 18 to 24 weeks’ gestation

Background A short cervix in the second trimester is known to increase the risk of preterm birth, which can be reduced with the administration of vaginal progesterone. However, some studies have suggested that a significant number of cases still experience preterm birth despite progesterone treatment. Objective This study was aimed to investigate the potential value of transvaginal cervical elasticity measured by E-Cervix as a predictor for spontaneous preterm birth (sPTB) in singleton pregnancies receiving progesterone treatment for a short cervix (CL ≤ 2.5 cm) diagnosed at 18 to 24 weeks’ gestation. Study design This prospective study was conducted at a single center premature high-risk clinic from January 2020 to July 2022. Singleton pregnancies with a short cervix at 18 to 24 weeks’ gestation were enrolled. Cervical elastography using E-Cervix was performed, and maternal and neonatal demographic characteristics, cervical length (CL), elasticity contrast index (ECI), cervical hardness ratio, mean internal os strain (IOS), and mean external os strain (EOS) were compared before and after progesterone treatment in sPTB and term birth groups. Multivariate logistic regression was used to analyze the association between elasticity parameters and spontaneous preterm birth. The screening performance of CL and optimal cervical elasticity parameters in predicting sPTB was evaluated using receiver-operating characteristic (ROC) curve analysis. Results A total of 228 singleton pregnant women were included in the study, among which 26 (11.4%) had sPTB. There were no significant differences in maternal characteristics and gestational age at enrollment between women with and without sPTB. At the start of progesterone treatment, there were no significant differences in cervical elasticity parameters between the two groups. After two weeks of progesterone treatment, women who had sPTB showed significantly higher levels of ECI, IOS, EOS (p = 0.0108, 0.0001, 0.016), and lower hardness ratio (p = 0.011) compared to those who had a full-term birth. Cervical length did not show significant differences between the two groups, regardless of whether progesterone treatment was administered before or after. Among the post-treatment cervical elasticity parameters, IOS and EOS were associated with a 3.38-fold and 2.29-fold increase in the risk of sPTB before 37 weeks (p = 0.032, 0.047, respectively). The AUROC of the combined model including CL, IOS, and EOS (0.761, 95% CI0.589–0.833) was significantly higher than the AUROC of CL alone (0.618, 95% CI 0.359–0.876). At a fixed false-positive of 13%, the addition of IOS and EOS in the CL model increased sensitivity from 34.6% to 57.6%, PPV from 25.7% to 36.5%, and NPV from 91.1% to 94.1%. Conclusion When assessing the risk of sPTB in singleton pregnancies with a short cervix receiving progesterone therapy, relying solely on cervical length is insufficient. It is crucial to also evaluate cervical stiffness, particularly the strain of the internal and external os, using cervical elastography.

Birth outcomes in mothers with hypertensive disorders and polycystic ovary syndrome: a population-based cohort study.

Is polycystic ovary syndrome (PCOS) associated with higher risks of extreme birth size and/or preterm birth in mothers with different hypertension types? PCOS was associated with additional risks of preterm birth in mothers with chronic hypertension and in singleton pregnancies of mothers with pre-eclampsia, and with higher risks of offspring born large for gestational age (LGA) in mothers with gestational hypertension. Women with PCOS are more likely to develop gestational hypertension, pre-eclampsia, and chronic hypertension. Although adverse birth outcomes have been frequently reported in mothers with PCOS, such associations in the setting of a hypertensive disorder remain unknown. This is a population-based cohort study including all live births 2004-2014 in Finland (n = 652 732). To ensure diagnosis specificity, mothers with diagnoses that could cause signs and symptoms resembling PCOS were excluded. Maternal diagnoses of PCOS, gestational hypertension, chronic hypertension, and pre-eclampsia were identified from the Finnish national registries. Generalized estimating equation and multivariable logistic regression were used to assess the adjusted odds ratio (aOR) and 95% CIs of preterm birth, very preterm birth, and offspring being small for gestational age (SGA) or LGA in hypertensive mothers with or without PCOS, using normotensive mothers without PCOS as reference. Of 43 902 (6.7%) mothers with hypertensive disorders, 1709 (3.9%) had PCOS. Significant interactions were detected for PCOS with hypertension on preterm birth, very preterm birth, offspring born SGA and LGA (Fpreterm = 504.1, Pinteraction < 0.001; Fvery preterm = 124.2, Pinteraction < 0.001; FSGA = 99.5, Pinteraction < 0.001; FLGA = 2.7, Pinteraction = 0.012, respectively). Using mothers with no hypertensive disorder and no PCOS as reference, the risks of preterm and very preterm birth were overrepresented in non-PCOS mothers with chronic hypertension or pre-eclampsia. PCOS was associated with higher risks of preterm birth (aORPCOS 4.02, 3.14-5.15 vs aORnon-PCOS 2.51, 2.32-2.71) in mothers with chronic hypertension, with significant interaction between the exposures (F = 32.7, Pinteraction < 0.001). PCOS was also associated with a higher risk of preterm birth in singleton pregnancies of mothers with pre-eclampsia (aORPCOS 7.33, 5.92-9.06 vs aORnon-PCOS 5.72, 5.43-6.03; F = 50.0, Pinteraction < 0.001). Furthermore, the associations of PCOS comorbid with chronic hypertension or pre-eclampsia was detected also for spontaneous births. Moreover, the risk of offspring LGA was higher in mothers with PCOS and gestational hypertension although lower in those with gestational hypertension alone (aORPCOS 2.04, 1.48-2.80 vs aORnon-PCOS 0.80, 0.72-0.89; F = 9.7, Pinteraction = 0.002), whereas for offspring SGA, the risks were comparable between hypertensive mothers with and those without PCOS. Information on medication treatment, gestational weeks of onset for pre-eclampsia and gestational hypertension, weight gain during pregnancy, and PCOS phenotypes were not available. All diagnoses were retrieved from registries, representing only those seeking medical care for their symptoms. The ICD-9 codes used to identify PCOS before year 1996 are known to underestimate the prevalence of PCOS, while the inclusion of anovulatory infertility as PCOS might introduce an overrepresentation bias, although PCOS constitutes 80% of anovulatory infertility. The risk of very preterm birth in relation to maternal PCOS and hypertensive disorders should be interpreted with caution owing to limited sample sizes. Multifetal pregnancies among maternal PCOS were too few for a subgroup analysis. Moreover, ART included IVF/ICSI only. Potential effects of other treatments, such as ovulation induction, were not examined. PCOS was associated with additional risks of preterm birth or offspring being LGA in hypertensive mothers, which varied between hypertension types. The exacerbated risks highlight consideration of PCOS in pregnancy counseling and management for women with hypertensive disorders. This study was supported by Shandong Provincial Natural Science Foundation, China [ZR2020MH064 to X.C.], the joint research funding of Shandong University and Karolinska Institute [SDU-KI-2019-08 to X.C. and C.L.], the Finnish Institute for Health and Welfare: Drug and pregnancy project [M.G.], the Swedish Research Council [2022-01188 to C.L.], the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institute Stockholm County Council [RS2021-0855 to C.L.], the Swedish Brain Foundation [FO2021-0412 to C.L.]. The funders had no role in study design, data collection, analysis, and interpretation, writing of the report or decision to submit for publication. The authors report no conflicts of interest. N/A.

P-752 Cervical cerclage versus vaginal progesterone in the prevention of preterm birth in singleton pregnancies among women with a short cervical length: A retrospective cohort study

Abstract Study question To compare the maternal and neonatal effects of cervical cerclage and vaginal progesterone in preventing singleton preterm births in women with a short cervical length. Summary answer Cervical cerclage showed no benefit in preventing preterm birth; however, it prolonged gestation by 39 days compared to vaginal progesterone treatment. What is known already Clinically, there may be a bias toward the choice of cervical cerclage if the cervix is short (&amp;lt;10 mm) and, similarly, toward vaginal progesterone use if the cervix is long (&amp;gt;30 mm). However, there are no clear treatment guidelines for the best options for singleton pregnant women with a CL between 10 and 30 mm. Furthermore, there is insufficient evidence to determine whether one treatment is superior to the other in preventing PTB and decreasing adverse neonatal outcomes in singleton pregnancies in such cases. Study design, size, duration Asymptomatic pregnant women having singleton pregnancies, with a CL between 10 and 30 mm, measured using transvaginal ultrasound at 12–26 weeks of gestation, who delivered at our hospital between January 2009 and August 2020, were included in our study. Based on the inclusion and exclusion criteria, 267 singleton pregnant women, of whom 116 were treated with cervical cerclage and 151 with vaginal progesterone, were finally included. Participants/materials, setting, methods Independent sample t-tests and differential analysis were used to analyze the data based on their distribution. The Cox semi-parametric regression model was used to analyze the gestation weeks at delivery and neonatal outcomes. The decision regarding cesarean delivery was based on a binary logistic regression model. Main results and the role of chance In the initial analysis, the number of preterm births was significantly higher in the cerclage group than in the vaginal progesterone group; however, after multivariate adjustment for confounding factors, the latency period from diagnosis to delivery was found to be significantly prolonged in the cerclage group. Limitations, reasons for caution There are currently no uniform criteria for determining whether study subjects are eligible for cervical cerclage or vaginal progesterone treatment, which may present some cases of noncompliance. Wider implications of the findings In our study, we found that cervical cerclage did not have significant advantages over vaginal progesterone treatment in preventing PTB. However, upon adjustment for confounding factors, it was shown to prolong the gestational age by 39 days compared to vaginal progesterone treatment. Trial registration number non-clinical trials

Cervical pessary for preventing preterm birth in singleton pregnancies.

Cervical pessary for preventing preterm birth in singleton pregnancies.

The introduction of a universal transvaginal cervical length screening program is associated with a reduced preterm birth rate

Midtrimester sonographic short cervix is a good predictor of preterm birth in singleton pregnancies. This study aimed to assess the impact of implementing a universal transvaginal cervical length screening program on preterm birth rate. This study consisted of 2 parts: a before-and-after multicenter study and a study on the ECHOCOL ("echo"="ultrasound" and "col"="cervix" in French) prospective cohort. We compared the rate of preterm birth before and after the introduction of universal cervical length screening at the time of midtrimester anatomy ultrasound. The multicenter before-and-after regional study included all women with a singleton pregnancy who gave birth after 24 weeks' gestation in the South East of France from January 1, 2012 to April 30, 2018. In parallel, the ECHOCOL cohort study was prospectively conducted from May 2015 to July 2018, including 17 maternity hospitals in the South East region of France. In case of asymptomatic short cervix <25 mm, treatments offered included 200 mg of vaginal progesterone, or cerclage, or a pessary until 34 weeks' gestation. We observed a significant decrease rate of preterm birth between periods A and B after multivariate analysis. (respectively, 5.8% vs 5.6%; adjusted odds ratio, 0.92; 95% confidence interval, 0.89-0.95; P<.0001). In parallel, the percentage of cervical length screening significantly increased from 28.9% in period A to 52.9% in period B (odds ratio, 2.76; 95% confidence interval, 2.71-2.80; P<.0001). Among the 3468 patients of the ECHOCOL prospective cohort, 38 (1.1%) asymptomatic short cervices were detected, and 192 patients gave birth prematurely (11 with an asymptomatic short cervix and 181 without). In the ECHOCOL cohort, a marked but statistically insignificant tendency toward a reduced rate of preterm birth before 37 weeks of gestation was observed (from 5.8% to 5.5%; adjusted odds ratio, 0.72; 95% confidence interval, 0.51-1.03; P=.068). This study showed a significantly lower rate of preterm birth after the implementation of a universal cervical length screening and treating policy during the second trimester of pregnancy. The clinical trial was registered under NCT02598323.

Assessment of Utero-Cervical Angle as an ultrasound screening tool to predict spontaneous preterm birth in singleton pregnancy

Introduction: Several attempts have been made from healthcare professionals around the world to determine the effective methods for early prediction and prevention of preterm birth. Aim of Work: The aim of this study was to determine the predictive value for spontaneous preterm birth by using transvaginal ultrasonography of the uterocervical angle (UCA) in pregnant women with singleton pregnancy. Subjects and methods: This study was a prospective Case-control study that was conducted at Obstetrics and Gynecology Department at Al-Zahraa University Hospital and Kafr Elshiekh General Hospital. Results:Utero Cervical angle (UCA) was significantly increased in preterm group&gt;95 degree compared to control group (p&lt; 0.001). Also, CL was significantly decreased in preterm group less than 27mm compared to control group .By using ROC-curve analysis, UC can predict preterm birth with accuracy (75.4%). The sensitivity, specificity, PPV and NPV was 70%, 76%, 74.47% and 71.7% respectively (p&lt; 0.001). CL can predict preterm birth with accuracy (66%). The sensitivity, specificity, PPV and NPV was 74%, 62%, 66.07% and 70.45% respectively (p= 0.003). Conclusion: Ultrasonographic measurement of uterocervical angle performed in routine vaginal ultrasound during second trimester is a useful strategy in the prediction of preterm birth in pregnancies and better than cervical length alone.

Comparison of two stitches versus one stitch for emergency cervical cerclage to prevent preterm birth in singleton pregnancies.

To compare the efficacy of two stitches versus one stitch in women with emergency cervical cerclage. A retrospective case-control study of 26 women with singleton pregnancies who underwent emergency cervical cerclage before 26 weeks. A comparison was made between patients with two stitches versus one stitch at the time of cervical cerclage placement. The primary outcome was gestational age (GA) at delivery and preterm birth (PTB) before 37, 34, 32, 28, and 24 weeks. Average GA at delivery in the two-stitches group was significantly greater than in the one-stitch group (32.71 ± 5.54 weeks vs 27.99 ± 4.70 weeks, P= 0.028). There were significant decreases in the incidence of spontaneous PTB at <34 weeks and less than 32 weeks in the two-stitches group (P= 0.034; P= 0.013, respectively). The neonatal intensive care unit (NICU) admissions rate and length of stay in the NICU in the two-stitches group were significantly reduced (P= 0.035 and P= 0.018, respectively). However, there was no significant difference in neonatal mortality between the two groups. Compared with emergency cervical cerclage placement with one stitch, the procedure with two stitches can prolong the pregnancy and improve the neonatal prognosis more effectively.

Ultrasonographic Assessment of the Cervix for Prediction of Spontaneous Preterm Birth in Singleton Pregnancies

Ultrasonographic Assessment of the Cervix for Prediction of Spontaneous Preterm Birth in Singleton Pregnancies

Uterocervical angle versus cervical length in the prediction of spontaneous preterm birth in singleton pregnancy.

To evaluate the predictive role of the uterocervical angle and the cervical length in preterm birth. This was cross-sectional analytical study, recruiting 167 women at high-risk for preterm birth (delivery before 37weeks of pregnancy). They had transvaginal ultrasound for evaluation of the uterocervical angle and the cervical length between at 30 and 32, 32+1 and 34, and 34+1 and 36+1 weeks of pregnancy. The primary outcome was to determine the predictive role of the uterocervical angle and the cervical length in preterm birth. The mean uterocervical angle was significantly greater in those who delivered preterm (115.4°±9.1° versus 101.1°±8.3°, p<0.001). The cervical length was insignificantly shorter in the same group (27.9±4.0 and 29.1±4.1mm, respectively, p=0.067). A uterocervical angle of 105° or more predicted preterm birth with sensitivity and specificity of 86.1% and 60.4%, respectively. A cervical length of 25mm or less had sensitivity and specificity of 27.8% and 85.8%, respectively. A uterocervical angle greater than 105° poses a high risk for preterm deliveries. It provides a higher diagnostic performance in high-risk patients than cervical canal length measurement.

Cervical stitch (cerclage) in combination with other treatments for preventing spontaneous preterm birth in singleton pregnancies.

Cervical stitch (cerclage) in combination with other treatments for preventing spontaneous preterm birth in singleton pregnancies.

Perfluoroalkyl substances exposure in early pregnancy and preterm birth in singleton pregnancies: a prospective cohort study

BackgroundPreterm birth (PTB, < 37 completed weeks’ gestation) is one of the global public health concerns. Epidemiologic evidence on the potential impact of perfluoroalkyl substances (PFAS) on PTB is still limited and inconsistent. We aimed to investigate the associations between prenatal PFAS exposure and PTB among singleton live births.MethodsWe studied 2849 mother-infant pairs in the Shanghai Birth Cohort (SBC) from 2013 to 2016. Ten PFAS in maternal plasma in early pregnancy (gestational age, median (interquartile range): 15 (13–16) weeks) were measured. Primary outcomes were duration of gestation, PTB, spontaneous PTB and clinically indicated PTB. A linear regression model was used to assess the associations between ln-transformed PFAS and duration of gestation (in weeks). Logistic regression models were applied to estimate the relative risks of these outcomes.ResultsThe incidence of overall PTB was 4.8% (95% confidence limit: 4.0–5.6%, n = 136) in this study population. In the linear regression analyses, PFAS were not associated with the duration of gestation after controlling for potential confounders. In the multiple logistic models, no significant associations were observed between PFAS and overall PTB, spontaneous or indicated PTB.ConclusionIn this prospective cohort study, we did not observe significant associations between maternal plasma PFAS concentrations in early pregnancy and gestational length, overall PTB, spontaneous or indicated PTB.

The use and abuse of meta-analysis.

The use and abuse of meta-analysis.

Cervical elastography using E-cervix for prediction of preterm birth in singleton pregnancies with threatened preterm labor

Objective E-Cervix™ (WS80A; Samsung, Seoul, Korea) elastography is a recent quantification tool to measure the stiffness of the cervix using strain elastography. The aim of this study was to evaluate the prediction performance of E-cervix for preterm birth in singleton gestation with threatened preterm labor (PTL). Methods This was a cohort study of singleton pregnancies without prior preterm birth presenting to obstetrics triage for threatened PTL between 23 0/7 and 33 6/7 week who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-cervix at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyses raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal os (IOS) and external os (EOS). Results Ninety-five singleton pregnancies without prior preterm birth and with threatened PTL between 23 0/7 and 33 6/7 week of gestation were included in the study. Forty-two (44.2%) had cervical length <25 mm, and were admitted for true PLT. Out of the 53 women with cervical length ≥25 mm, 40 (75.5%) were discharged, and 13 (24.5%) were admitted. Women with threatened PTL but without true PTL, had significantly higher HR compared to those with true PTL (49.0 ± 20.9% versus 34.8 ± 19.6%; p < .01), and significantly lower stiffness of cervical IOS and EOS. Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm, in overall cohort, and in the subset of only women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01). Conclusions Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL. Women with low HR, especially with HR less than 50 or 35%, are at increased risk of PTB. Condensation Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01). Key message Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL.

Plasma oxylipins and unesterified precursor fatty acids are altered by DHA supplementation in pregnancy: Can they help predict risk of preterm birth?

Oxidized lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids, collectively known as oxylipins, are bioactive signaling molecules that play diverse roles in human health and disease. Supplementation with n-3 docosahexaenoic acid (DHA) during pregnancy has been reported to decrease the risk of preterm birth in singleton pregnancies, which may be due to effects of DHA supplementation on oxylipins or their precursor n-6 and n-3 fatty acids. There is only limited understanding of the levels and trajectory of changes in plasma oxylipins during pregnancy, effects of DHA supplementation on oxylipins and unesterified fatty acids, and whether and how oxylipins and their unesterified precursor fatty acids influence preterm birth. In the present study we used liquid chromatography-tandem mass spectrometry to profile oxylipins and their precursor fatty acids in the unesterified pool using plasma samples collected from a subset of pregnant Australian women who participated in the ORIP (Omega-3 fats to Reduce the Incidence of Prematurity) study. ORIP is a large randomized controlled trial testing whether daily supplementation with n-3 DHA can reduce the incidence of early preterm birth compared to control. Plasma was collected at study entry (≈pregnancy week 14) and again at ≈week 24, in a subgroup of 48 ORIP participants—12 cases with spontaneous preterm (<37 weeks) birth and 36 matched controls with spontaneous term (≥40 weeks) birth. In the combined preterm and term pregnancies, we observed that in the control group without DHA supplementation unesterified AA and AA-derived oxylipins 12-HETE, 15-HETE and TXB2 declined between weeks 14–24 of pregnancy. Compared to control, DHA supplementation increased unesterified DHA, EPA, and AA, DHA-derived 4-HDHA, 10-HDHA and 19,20-EpDPA, and AA-derived 12-HETE at 24 weeks. In exploratory analysis independent of DHA supplementation, participants with concentrations above the median for 5-lipoxygenase derivatives of AA (5-HETE, Odds Ratio (OR) 8.2; p = 0.014) or DHA (4-HDHA, OR 8.0; p = 0.015) at 14 weeks, or unesterified AA (OR 5.1; p = 0.038) at 24 weeks had higher risk of spontaneous preterm birth. The hypothesis that 5-lipoxygenase-derived oxylipins and unesterified AA could serve as mechanism-based biomarkers predicting spontaneous preterm birth should be evaluated in larger, adequately powered studies.

Effectiveness of the cervical pessary for the prevention of preterm birth in singleton pregnancies with a short cervix: a meta-analysis of randomized trials

To assess the efficacy of cervical pessary application for the prevention of spontaneous preterm birth (SPB) in singleton pregnancies with a sonographically measured short cervix. Searches were conducted in PubMed-Medline, Embase, Scopus, Web of Science, and Cochrane Library, and clinical trial registries for randomized controlled trials (RCTs) published in all languages from inception through 28 July 2018. Inclusion criteria were registered RCTs of singleton pregnants with a short cervix (≤ 25mm) measured at 22-24weeks comparing the use of a cervical pessary versus controls over the risk of SPB. Risk of bias was evaluated with the Cochrane tool. Risk ratios (RRs) and mean differences and 95% confidence intervals (CIs) were calculated. We identified three RCTs meeting defined inclusion criteria, including a total of 1612 pregnancies (805 used a cervical pessary). SPB risk at < 37 was lower for participants using the pessary (RR 0.46; 95% CI 0.28-0.77). Pessary application was associated with a higher risk of presenting vaginal discharge (RR 2.05; 95% CI 1.82-2.31). There were no significant differences between pessary users and controls in terms of SPB at < 28 and < 34weeks, and for any type of preterm birth < 34weeks; mean gestational age and infant weight at delivery; and the risks of chorioamnionitis, cesarean delivery, and perinatal or neonatal outcomes. Sub-analysis by risk of bias showed that there was a lower risk of SPB < 34weeks (RR 0.33; 95% CI 0.16-0.66) in two RCTs with low risk of bias. Cervical pessary application was associated with a reduced risk of SPB at < 37weeks and a higher risk of vaginal discharge.

470: Comparison of physical examination and ultrasound indicated cerclages between singleton and twin pregnancies

Physical examination indicated cerclage (PEIC) and Ultrasound indicated cerclage (UIC) are well stablished strategies for reducing preterm birth in singleton pregnancies. However, their indication in twin pregnancies is a controversial issue as no data from RCT are available to demonstrate their efficacy. The aim of this study was to compare perinatal outcomes after PEIC and UIC between singleton and twin gestations. Retrospective observational study including patients having PEIC or UIC in Hospital Clinic of Barcelona, from 2007 to 2016. Exclusion criteria were: monochorionic-monoamniotic placentation, major fetal anomalies and elective termination of pregnancy. Wilcoxon-test and Chi-square and Fisher’s exact test were used to compare continuous and categorical variables, respectively. Differences were considered statistically significant when p-value <0.05. 129 women with cercalge were evaluated. 60 women (43 singletons and 17 twins) underwent PEIC, and 2singleton pregnancies were lost to follow-up. 69women (56 singleton and 13 twins) underwent UIC, and 7 (6 singleton and 1 twin) were lost to follow up. Basal characteristics were similar between both PEIC groups, except that there were more twin pregnancies conceived by ART. Between UIC groups, there were more nulliparous and women with a previous preterm birth among twin pregnancies. Perinatal outcomes of PEIC and UIC are shown in Tables 1 and 2, respectively. No significant differences in the perinatal outcomes between singleton and twin pregnancies who underwent PEIC were observed. Regarding UIC, and despite latency to delivery in twins with UIC was significantly shorter compared to singletons, latency to delivery reached a median of 12 weeks. More PPROM and NICU admission were observed in twin pregnancies who underwent a UIC. Outcomes of PEIC were comparable between singleton and twin pregnancies. Outcome of UIC in twins show worse results compared to singletons but latency to delivery is still clinically relevant. Therefore, PEIC and UIC in twin pregnancies deserve further study as they may play a role as a therapeutic approach.View Large Image Figure ViewerDownload Hi-res image Download (PPT)