Re-evaluation of gestational age as a predictor for subsequent preterm birth

Economic burden of adverse perinatal outcomes from births to age 5 years in high-income settings: a protocol for a systematic review

BACKGROUND

Adverse perinatal outcomes such as preterm, small for gestational age, low birth weight, congenital anomalies, stillbirth and neonatal death have devastating impacts on individuals, families and societies, with significant lifelong health implications. Despite extensive knowledge of the significant and lifelong health implications of adverse perinatal outcomes, information on the economic burden is limited. Estimating this burden will be crucial for designing cost-effective interventions to reduce perinatal morbidity and mortality. Thus, we will quantify the economic burden of adverse perinatal outcomes from births to age 5 years in high-income countries.

METHODS AND ANALYSIS

A systematic review of all primary studies published in English in peer-reviewed journals on the economic burden for at least one of the adverse perinatal outcomes in high-income countries from 2010 will be searched in databases-MEDLINE (Ovid), EconLit, CINAHL (EBSCO), Embase (Ovid) and Global Health (Ovid). We will also search using Google Scholar and snowballing of the references list of included articles. The search terms will include three main concepts-costs, adverse perinatal outcome(s) and settings. We will use the Consolidated Health Economics Evaluation Reporting Standards 2022 and 17 criteria from the critical appraisal of cost-of-illness studies to assess the quality of each study. We will report the findings based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 statement. Costs will be converted into a common currency (US dollar), and we will estimate the pooled cost and subgroup analysis will be done. The reference lists of included papers will be reviewed.

ETHICS AND DISSEMINATION

This systematic review will not involve human participants and requires no ethical approval. The results of this review will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42023400215.

Trends and risk of recurrent preterm birth in pregnancy cohorts in rural Bangladesh, 1990-2019

INTRODUCTION

A history of preterm birth reportedly increases the risk of subsequent preterm birth. This association has primarily been studied in high-income countries and not in low-income settings in transition with rapidly descending preterm birth figures. We evaluated the population-based trends of preterm births and recurrent preterm births and the risk of preterm birth recurrence in the second pregnancy based on prospectively studied pregnancy cohorts over three decades in Matlab, Bangladesh.

METHODS

A population-based cohort included 72 160 live births from 1990 to 2019. We calculated preterm birth and recurrent preterm birth trends. We assessed the odds of preterm birth recurrence based on a subsample of 14 567 women with live-born singletons in their first and second pregnancies. We used logistic regression and presented the associations by OR with a 95% CI.

RESULTS

The proportion of preterm births decreased from 25% in 1990 to 13% in 2019. The recurrent preterm births had a similar, falling pattern from 7.4% to 3.1% across the same period, contributing 27% of the total number of preterm births in the population. The odds of second pregnancy preterm birth were doubled (OR 2.18; 95% CI 1.96 to 2.43) in women with preterm birth compared with the women with term birth in their first pregnancies, remaining similar over the study period. The lower the gestational age at the first birth, the higher the odds of preterm birth in the subsequent pregnancy (test for trend p<0.001).

CONCLUSION

In this rural Bangladeshi setting, recurrent preterm births contributed a sizeable proportion of the total number of preterm births at the population level. The increased risk of recurrence remained similar across three decades when the total proportion of preterm births was reduced from 25% to 13%.

Prediction Models for Adverse Pregnancy Outcomes in India: Methodological Considerations for an Emerging Topic

Stillbirth is over-represented in lower and lower-middle-income countries and understandably this has motivated greater research investment in the development of prediction models. Prediction is particularly challenging for pregnancy outcomes because only part of the population is represented in observational research. Notably, unrecognised pregnancies and miscarriages are typically excluded from the development of prediction models and the consequences of such selection are not well understood. Other methodological challenges in developing stillbirth prediction models are within the control of the researcher. Identifying whether the intended model is for aetiological explanation versus prediction, attainment of a sufficiently large representative sample, and internal and external validation are among such methodological considerations. These considerations are discussed in relation to a recently published study on prediction of stillbirth after 28 weeks of pregnancy for women with hypertensive disorders of pregnancy in India. The predictive ability of this model amounts to the flip of a coin. Future screening based on such a model may be expensive, increase psychological distress among patients and introduce additional iatrogenic perinatal morbidities from over-treatment. Future research should address the methodological considerations described in this article.

Gestational age as a predictor for subsequent preterm birth in New South Wales, Australia

Background

There is no validated evidence base on predictive ability and absolute risk of preterm birth by gestational age of the previous pregnancy.

Methods

We conducted a retrospective cohort study of mothers who gave birth to their first two children in New South Wales, 1994–2016 (N = 517,558 mothers). For each week of final gestational age of the first birth, we calculated relative and absolute risks of subsequent preterm birth.

Results

For mothers whose first birth had a gestational age of 22 to 30 weeks the absolute risks of clinically significant preterm second birth (before 28, 32, and 34 weeks) were all less than 14%. For all gestational ages of the first child the median gestational ages of the second child were all at least 38 weeks. Sensitivity and positive predictive values were all below 30%.

Conclusion

Previous gestational age alone is a poor predictor of subsequent risk of preterm birth.