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Caesarean birth and risk of subsequent preterm birth: a retrospective cohort study
Author(s) -
Williams C,
Fong R,
Murray S Murray,
Stock SJ
Publication year - 2021
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.16566
Subject(s) - medicine , obstetrics , retrospective cohort study , caesarean section , pregnancy , odds ratio , birth trauma , gestation , cohort study , surgery , biology , genetics
Objective To determine the risk of spontaneous and medically indicated preterm birth associated with mode of birth in previous term‐born pregnancy. Design Retrospective cohort study. Setting Two UK maternity units. Population or sample A total of 16 340 women with first two consecutive singleton births and the first birth at term. Methods Retrospective cohort study using routinely collected clinical data. Main outcome measures Incidence of spontaneous preterm birth and medically indicated preterm birth at less than 37 weeks of gestation after term birth, in relation to mode of birth in first pregnancy. Subgroup analysis on cervical dilatation at the time of first caesarean birth. Results Compared with vaginal birth, emergency caesarean birth at full dilatation was associated with an increase in spontaneous preterm birth (2.3% vaginal birth versus 4.5% full dilatation caesarean; adjusted odds ratio [aOR] 3.29, 95% CI 2.02–5.13, P < 0.001). Elective caesarean, emergency caesarean at <4 cm dilatation, and emergency caesarean at 4–9 cm dilatation were associated with increased medically indicated preterm birth (0.8% vaginal births versus 1.9% elective caesarean, 3.3% <4 cm caesarean, 1.3% 4–9 cm caesarean; aOR 2.30, 95% CI 1.19–4.15, P = 0.009; aOR 4.68, 95% CI 2.98–7.24, P < 0.001; and aOR 2.43, 95% CI 1.43–4.00, P = 0.001, respectively). Conclusions Term caesarean in the first stage of labour or performed prelabour is associated with medically indicated preterm birth. Term caesarean in the second stage of labour is associated with spontaneous preterm birth. Tweetable abstract Caesarean in the second stage of labour is associated with spontaneous preterm birth.