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Impact of gestational hypertension and pre-eclampsia on preterm birth in China: a large prospective cohort study

Hang An, Ming Jin, Zhi-Wen Li, Le Zhang, Hong-Tian Li, Ya-Li Zhang, R. Ye, Nan Li

BMJ Open, 2022

200 participants · 55 citations

Abstract

Objective To investigate the impact of gestational hypertension and pre-eclampsia on preterm birth. Design The data were collected from the China–US Collaborative Project for Neural Tube Defect Prevention; this was a large population-based cohort study. Setting and participants We selected participants registered in two southern provinces, for whom we had exact information on gestational blood pressure and pregnancy outcomes, and who were not affected by chronic hypertension. In total, 200 103 participants were recruited from 1993 to 1995. Outcome measures Preterm birth was defined as a singleton pregnancy and birth before 37 gestational weeks. Results The incidences of gestational hypertension and pre-eclampsia were 5.47% and 5.44%, respectively, for women who gave birth at full term, and 5.63% and 7.33%, respectively, for those who gave birth preterm. After adjusting for potential confounders, the risk ratios (RRs) of preterm birth in women with gestational hypertension and pre-eclampsia were 1.04 (95% CI 0.98 to 1.11) and 1.39 (95% CI 1.25 to 1.55), respectively. The associations were stronger for early-onset (<28 weeks of gestation) gestational hypertension (adjusted RR=2.13, 95% CI 1.71 to 2.65) and pre-eclampsia (adjusted RR=8.47, 95% CI 5.59 to 12.80). Conclusions Pre-eclampsia was associated with a higher risk of preterm birth. The early-onset gestational hypertension and pre-eclampsia were associated with more severe risks than late-onset conditions.

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 200 participants or records.

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