Racial and social predictors of longitudinal cervical measures: the Cervical Ultrasound Study

Prior Spontaneous or Induced Abortion Is a Risk Factor for Cervical Dysfunction in Pregnant Women: a Systematic Review and Meta-analysis

A history of abortion is associated with cervical dysfunction during pregnancy, but there remains uncertainty about whether risk can be stratified by the abortion type, the abortion procedure, or number of previous abortions. The objective of this study was to verify the relationship between cervical dysfunction measures in pregnancies with and without a history of termination. Embase and Medline databases were searched from 01 January 1960 to 01 March 2022 resulting in a full-text review of 28 studies. The Newcastle-Ottawa Scale (NOS) was used to assess the quality and risk of bias for non-randomized studies. The meta-analysis consisted of 6 studies that met all inclusion and exclusion criteria and included a combined total of 2,513,044 pregnancies. Cervical dysfunction was defined as either cervical insufficiency/incompetence in 4 of the studies and as short cervix in the others. Results from a random-effects model using reported adjusted odds ratios (aOR) estimated an increase in the odds of 2.71 (95% CI 1.76, 4.16) for cervical dysfunction in the current pregnancy related to a history of induced or spontaneous abortion. Subgroup analyses with only induced abortions (surgical/medical) estimated an aOR of 2.54 (95% CI 1.41, 4.57), while studies limited to surgical abortions had an aOR of 4.08 (95% CI 2.84, 5.86). The risk of cervical dysfunction in the current pregnancy was also found to be dependent on the number of previous abortions. In this meta-analysis, a prior history of abortion, and specifically induced abortions, was associated with cervical dysfunction. The protocol was registered in PROSPERO (CRD42020209723).

Study protocol to quantify the genetic architecture of sonographic cervical length and its relationship to spontaneous preterm birth

INTRODUCTION

A short cervix (cervical length <25 mm) in the midtrimester (18-24 weeks) of pregnancy is a powerful predictor of spontaneous preterm delivery. Although the biological mechanisms of cervical change during pregnancy have been the subject of extensive investigation, little is known about whether genes influence the length of the cervix, or the extent to which genetic factors contribute to premature cervical shortening. Defining the genetic architecture of cervical length is foundational to understanding the aetiology of a short cervix and its contribution to an increased risk of spontaneous preterm delivery.

METHODS/ANALYSIS

The proposed study is designed to characterise the genetic architecture of cervical length and its genetic relationship to gestational age at delivery in a large cohort of Black/African American women, who are at an increased risk of developing a short cervix and delivering preterm. Repeated measurements of cervical length will be modelled as a longitudinal growth curve, with parameters estimating the initial length of the cervix at the beginning of pregnancy, and its rate of change over time. Genome-wide complex trait analysis methods will be used to estimate the heritability of cervical length growth parameters and their bivariate genetic correlation with gestational age at delivery. Polygenic risk profiling will assess maternal genetic risk for developing a short cervix and subsequently delivering preterm and evaluate the role of cervical length in mediating the relationship between maternal genetic variation and gestational age at delivery.

ETHICS/DISSEMINATION

The proposed analyses will be conducted using deidentified data from participants in an IRB-approved study of longitudinal cervical length who provided blood samples and written informed consent for their use in future genetic research. These analyses are preregistered with the Center for Open Science using the AsPredicted format and the results and genomic summary statistics will be published in a peer-reviewed journal.

Cervical insufficiency: a noteworthy disease with controversies

Cervical insufficiency (CI) is a mainly disease leading to recurrent abortions and preterm birth which may present in about 1% of obstetric populations. Recurrent pregnancy losses caused by CI incur serious economic burdens on society as well as huge psychological burdens to family members. However, many patients even clinicians in some areas of the world still remain confused about this disease. At the same time, the etiology of CI is still uncertain and it is still a controversial disease in diagnosis and treatment. This article summarizes the potential risk factors associated with CI, which could be worthy of attention and helpful for future research. It also reviews the methods for diagnosis and treatment of CI to better understand this noteworthy disease, as well as presents the related consensus and controversies according to the newly updated guidelines, which has practical significance for conducting more in-depth investigations in the future.

Spontaneous preterm birth and cervical length in a pregnant Asian population

Objective

Preterm birth (birth before 37 weeks of completed gestation) is the leading cause of neonatal death, and has an incidence of 5–13% which is believed to be on the rise. The objective of this study was to determine the rate of spontaneous preterm birth and investigate the relationship between preterm birth and cervical length in a pregnant Asian population.

Materials and methods

A prospective observational study between September 2010 and November 2013 was performed at KK Women’s and Children’s Hospital, Singapore. 1013 women with single viable pregnancies were recruited at less than 14 weeks of gestation between September 2010 and November 2013, excluding those with multiple gestation, pre-existing autoimmune or renal disease or those with current pregnancies complicated by aneuploidy or fetal anomalies. Participant characteristics were obtained from an interviewer-administered questionnaire at the first recruitment visit. Cervical length was measured using ultrasound at each of the 4 antenatal visits (Visit 1: < 14 weeks, Visit 2: 18–22 weeks, Visit 3: 28–32 weeks and Visit 4: > 34 weeks) using the Fetal Medicine Foundation protocol. Data on pregnancy outcomes were obtained from obstetric case notes and records. The main outcome measure examined in this study was that of spontaneous preterm birth and its relationship to cervical length.

Results

There was a significantly shorter cervical length both in the 2nd trimester (18 to 22 weeks) and the 3rd trimester (28 to 32 weeks) in the preterm birth group compared to the term birth group (p = 0.028 and p < 0.001 respectively). In the first trimester (11 to 14 weeks), there was no statistically significant difference in cervical length between the two groups (p = 0.425). ROC curve analysis for cervical length in the preterm birth group for 18 to 22 weeks and 28 to 32 weeks showed an AUC of 0.605 and 0.725 respectively. At 28 to 32 weeks of gestation, a cut-off level at 2.49 cm has a sensitivity of 54.8%, specificity of 82.5%, negative predictive value of 97.9% and positive predictive value of 11.1%.

Conclusion

There is a significantly shorter cervical length in the 2nd and 3rd trimester in the preterm birth group. Cervical length is a moderate predictor of preterm birth with good negative predictive value and a relatively good specificity. Ultrasound cervical length screening for pregnant Asian women between 18 and 22 weeks of gestation with a cutoff of ≥ 2.48cm can help to identify a group of women who are at risk for preterm birth.

Cervical pathways for racial disparities in preterm births: the Preterm Prediction Study

Purpose: Racial disparities in preterm birth have been long recognized, but the social and biological mechanisms for these differences are unclear. Our analysis had three goals: (1) to determine the relation between race and other social risk factors and cervical structure; (2) to determine whether social factors mediate the relation between race and cervical structure; and (3) to determine whether racial disparities in preterm birth (PTB) are mediated through changes in cervical structure observed earlier in pregnancy. Materials and methods: Data from the Maternal Fetal Medicine Unit network Preterm Prediction Study were used to examine the relation between race and other social factors and cervical properties throughout pregnancy in 2920 black and white women. Outcomes included cervical length and dilation; cervical score (cervical length-internal dilation); and whether membranes protruded at 22-24 and 26-29 weeks. Race, education, income, insurance type, and marital status were examined as predictors of the outcomes using linear and logistic regression, adjusting for age, BMI, parity, and smoking. Mediation analysis was used to examine whether (a) any social factors explained racial differences in cervical properties, and (b) whether cervical properties mediated racial differences in risk for preterm birth. Results: Shorter cervical length, especially at a subject's first visit, was associated with black race (adjusted beta -1.56 mm, p < .01) and lower income (adjusted beta -1.48, p =.05). External dilation was not associated with social factors, while internal dilation was associated with black race and lower education. Black race and marital status were associated with lower cervical score. There was no evidence of mediation of the racial effect on cervical properties by any social factor. Shorter cervical length, dilation, and score were all associated with preterm birth (p < .01). Mediation analysis indicated that each of these mediated the effect of race, but explained a small proportion of the total effect (15-25%). Conclusions: Race, and, to a lesser extent, other social factors are correlated with adverse cervical properties. This pathway could explain a proportion of the racial disparity in preterm birth.

DASH, the data and specimen hub of the National Institute of Child Health and Human Development

The benefits of data sharing are well-established and an increasing number of policies require that data be shared upon publication of the main study findings. As data sharing becomes the new norm, there is a heightened need for additional resources to drive efficient data reuse. This article describes the development and implementation of the Data and Specimen Hub (DASH) by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) to promote data sharing from NICHD-funded studies and enable researchers to comply with NIH data sharing policies. DASH’s flexible architecture is designed to archive diverse data types and formats from NICHD’s broad scientific portfolio in a manner that promotes FAIR data sharing principles. Performance of DASH over two years since launch is promising: the number of available studies and data requests are growing; three manuscripts have been published from data reanalysis, all within two years of access. Critical success factors included NICHD leadership commitment, stakeholder engagement and close coordination between the governance body and technical team.