Caesarean delivery and subsequent pregnancy interval: a systematic review and meta-analysis

O’Neill, Sinéad M; Kearney, Patricia M.; Kenny, Louise C.; Henriksen, Tine Brink; Lutomski, Jennifer E.; Greene, Richard A.; Khashan, Ali S.

doi:10.1186/1471-2393-13-165

Cited by 44 publications

(49 citation statements)

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“…Non-experimental assessment of the relationship between cesarean delivery and subsequent subfertility also represents a situation where the potential for confounding by extraneous aspects of the indication exists [14]. Subfertility, often measured by time to pregnancy or the interpregnancy interval, does not constitute an intended or known unintended effect of cesarean delivery.…”

Section: Confounding By Extraneous Aspects Of the Indicationmentioning

confidence: 99%

“…Subfertility, often measured by time to pregnancy or the interpregnancy interval, does not constitute an intended or known unintended effect of cesarean delivery. However, indications for cesarean delivery are typically associated with various factors that influence fertility, including maternal age, height, body mass index, obstetric history, and socioeconomic status [14]. Control of confounding due to such extraneous aspects of the indicationincluding constitutional, behavioral, and lifestyle factorsshould be feasible through standard epidemiologic means; again, however, care with methods design may be needed for appropriately controlling confounding by socioeconomic status [13].…”

Section: Confounding By Extraneous Aspects Of the Indicationmentioning

confidence: 99%

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Confounding by Indication and Related Concepts

2014

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The term confounding by indication is increasingly used in the literature, although the concept has lost much of its original meaning. The literature includes instances where confounding by indication is equated with confounding in general or reverse causality, and other instances where it is used to refer to confounding by contraindication. In this paper, we review concepts related to confounding by indication in studies of intended effects, confounding by indication and contraindication in studies of unintended effects, and confounding by extraneous aspects of the indication. We also discuss non-experimental methods to address confounding by indication, including design strategies (e.g., restriction to a domain free of the indication) and statistical techniques (e.g., propensity score matching). We argue for greater conceptual and semantic clarity with regard to the different forms of confounding by indication and conclude that nonexperimental methods do not adequately address this bias in studies of intended effects when the indication defies quantification.

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Section: Confounding By Extraneous Aspects Of the Indicationmentioning

confidence: 99%

Section: Confounding By Extraneous Aspects Of the Indicationmentioning

confidence: 99%

Confounding by Indication and Related Concepts

2014

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“…35 The results of this study are consistent with previous studies, which have reported lower rates of childbearing after cesarean compared with vaginal delivery. 5,6,18 However, there was 1 previous study of a cohort of primiparous Danish women who were trying to conceive that reported no difference in rate of conception when comparing women who had delivered by unplanned cesarean (112 women) with those who had spontaneous vaginal delivery (585 women), although in that study women who had attempted pregnancy for more than 6 menstrual cycles were excluded. 36 To our knowledge, this is the first prospective study beginning before first childbirth that measured unprotected intercourse in each month over the course of 36 months after first childbirth, to test whether women who delivered by cesarean were less likely to try to conceive subsequently than women who delivered vaginally, as has been hypothesized, or less likely to conceive after unprotected intercourse.…”

Section: Discussionmentioning

confidence: 97%

Association Between Mode of First Delivery and Subsequent Fecundity and Fertility

et al. 2020

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IMPORTANCE More than 20% of births globally are by cesarean delivery, including more than 30% in the US. Prior studies have reported lower rates of childbearing after cesarean delivery, but it is not clear if this is due to maternal choice or lower conception rates. OBJECTIVE To investigate the association between mode of first delivery and subsequent conceptions and live births. DESIGN, SETTING, AND PARTICIPANTS The First Baby Study was a multicenter prospective cohort study of women aged 18 to 35 years with singleton pregnancies, enrolled and interviewed before first childbirth, who delivered in Pennsylvania from 2009 to 2011 and were followed up for 36 months after delivery (until April 2014). Data analysis for this study took place between May and July 2019 and in January 2020. EXPOSURES Mode of first delivery (cesarean or vaginal). MAIN OUTCOMES AND MEASURES Rates of subsequent conceptions and live births. Discrete-time Cox proportional hazard regression models were used to compare the rate of subsequent conception (vaginal vs cesarean) among those who completed the 36-month survey, accounting for reported months of unprotected intercourse during the follow-up period and adjusting for relevant covariates. A log binomial regression was used to compare the age-adjusted rate of subsequent live birth (vaginal vs cesarean) among those who completed the 36-month survey. RESULTS The study population consisted of 2423 women who were retained to the 36-month survey (mean [SD] age at baseline was 27.2 [4.4] years and 712 [29.4%] delivered by cesarean). There were 2046 women who had unprotected intercourse during the follow-up period, 2021 of whom provided data on months of unprotected intercourse. Cesarean delivery was associated with lower rates of conception after unprotected intercourse during the follow-up period (413 of 599 [68.9%]) compared with vaginal delivery (1090 of 1422 [76.7%]) (adjusted hazard ratio, 0.85; 95% CI, 0.74-0.96). Cesarean delivery was also associated with reduced likelihood of a subsequent live birth (305 women [42.8%]) compared with vaginal delivery (857 women [50.1%]), with an age-adjusted risk ratio of 0.83 (95% CI, 0.75-0.92). CONCLUSIONS AND RELEVANCE In the 3 years following first childbirth, women who delivered their first child by cesarean had lower rates of conception after unprotected intercourse, and fewer of these women had a second child than those who delivered vaginally.

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“…Finally, if there is an association between CS and sterility, it is clear that CS increased the delay of the second pregnancy. In 2013, O'Neill and colleagues reviewed 11 articles including a total of 750,407 women, and their studies indicated that there was an increased waiting time to the next pregnancy and risk of subfertility among women with CS [21].…”

Section: Discussionmentioning

confidence: 99%