Short interpregnancy intervals and adverse perinatal outcomes in high‐resource settings: An updated systematic review

Moskosky

Ananth

et al. 2018

Self Cite

Background Meta‐analyses of observational studies have shown that women with a shorter interpregnancy interval (the time from delivery to start of a subsequent pregnancy) are more likely to experience adverse pregnancy outcomes, such as preterm delivery or small for gestational age birth, than women who space their births further apart. However, the studies used to inform these estimates have methodological shortcomings. Methods In this commentary, we summarise the discussions of an expert workgroup describing good practices for the design, analysis, and interpretation of observational studies of interpregnancy interval and adverse perinatal health outcomes. Results We argue that inferences drawn from research in this field will be improved by careful attention to elements such as: (a) refining the research question to clarify whether the goal is to estimate a causal effect vs describe patterns of association; (b) using directed acyclic graphs to represent potential causal networks and guide the analytic plan of studies seeking to estimate causal effects; (c) assessing how miscarriages and pregnancy terminations may have influenced interpregnancy interval classifications; (d) specifying how key factors such as previous pregnancy loss, pregnancy intention, and maternal socio‐economic position will be considered; and (e) examining if the association between interpregnancy interval and perinatal outcome differs by factors such as maternal age. Conclusion This commentary outlines the discussions of this recent expert workgroup, and describes several suggested principles for study design and analysis that could mitigate many potential sources of bias.

Section: Introductionmentioning

confidence: 99%

Good practices for the design, analysis, and interpretation of observational studies on birth spacing and perinatal health outcomes

Moskosky

Ananth

et al. 2018

Self Cite

“…In accordance with National Academy of Medicine (formerly the Institute of Medicine) guideline development standards, the purpose of this systematic review was to summarise the association between short interpregnancy interval and adverse maternal outcomes in high‐resource settings in order to inform development of recommendations on birth spacing for the United States. The association between short interpregnancy interval and adverse perinatal outcomes in high‐resource settings is reported separately in this journal supplement in a companion paper …”

Section: Introductionmentioning

confidence: 99%

Short interpregnancy intervals and adverse maternal outcomes in high‐resource settings: An updated systematic review

Nelson

Stidd

et al. 2018

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Background Currently, no federal guidelines provide recommendations on healthy birth spacing for women in the United States. This systematic review summarises associations between short interpregnancy intervals and adverse maternal outcomes to inform the development of birth spacing recommendations for the United States. Methods PubMed/Medline, POPLINE, EMBASE, CINAHL, the Cochrane Database of Systematic Reviews, and a previous systematic review were searched to identify relevant articles published from 1 January 2006 and 1 May 2017. Included studies reported maternal health outcomes following a short versus longer interpregnancy interval, were conducted in high‐resource settings, and adjusted estimates for at least maternal age. Two investigators independently assessed study quality and applicability using established methods. Results Seven cohort studies met inclusion criteria. There was limited but consistent evidence that short interpregnancy interval is associated with increased risk of precipitous labour and decreased risks of labour dystocia. There was some evidence that short interpregnancy interval is associated with increased risks of subsequent pre‐pregnancy obesity and gestational diabetes, and decreased risk of preeclampsia. Among women with a previous caesarean delivery, short interpregnancy interval was associated with increased risk of uterine rupture in one study. No studies reported outcomes related to maternal depression, interpregnancy weight gain, maternal anaemia, or maternal mortality. Conclusions In studies from high‐resource settings, short interpregnancy intervals are associated with both increased and decreased risks of adverse maternal outcomes. However, most outcomes were evaluated in single studies, and the strength of evidence supporting associations is low.

“…Studies of short interpregnancy interval on adverse pregnancy outcomes, particularly perinatal outcomes, may be susceptible to positive residual confounding if there is incomplete control for maternal socio‐economic position, pregnancy intention, and prior pregnancy perinatal loss. This conclusion is supported by the attenuated effect on perinatal outcomes after adjusting for maternal demographics and socio‐economic position . The expert work group did not reach consensus on how complete control of confounding could be achieved, but did agree that current research could be improved by more diverse study designs, analyses, and sources of data.…”

Section: Methodological Limitations Of Studiesmentioning

confidence: 99%

“…The new reviews incorporated more narrow inclusion criteria by restricting included studies to those that defined short birth spacing using the interpregnancy interval (with short interpregnancy interval defined as some duration less than 24 months versus a well‐defined longer duration), controlled for at least maternal age (and socio‐economic position, for perinatal outcomes), and were conducted within countries categorised as “very high” on the United Nations Human Development Index . Details on the systematic review methodology, including study quality assessment, and the summary of evidence can be found in other manuscripts in this journal supplement . Studies employing a sibling comparison design, which compared differences in a woman's interpregnancy intervals and birth outcomes using a within‐woman analysis, were considered separately from the studies employing a conventional between‐women analysis.…”

Section: Evidence Presented On Short Interpregnancy Interval and Advementioning

confidence: 99%

“…The updated systematic review on short interpregnancy intervals and perinatal outcomes included 21 studies published since 2006 and 11 studies from the previous review that met our revised inclusion criteria . Definitions of short interpregnancy interval varied across studies (eg <3 months, <9 months, and 13‐24 months) with most studies specifying more than one mutually exclusive short interpregnancy interval (eg <6, 6‐11, and 12‐17 months).…”

Section: Evidence Presented On Short Interpregnancy Interval and Advementioning

confidence: 99%

See 1 more Smart Citation

Report of the Office of Population Affairs’ expert work group meeting on short birth spacing and adverse pregnancy outcomes: Methodological quality of existing studies and future directions for research

Ahrens

Ananth

et al. 2018

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Background The World Health Organization ( WHO ) recommends that women wait at least 24 months after a livebirth before attempting a subsequent pregnancy to reduce the risk of adverse maternal, perinatal, and infant health outcomes. However, the applicability of the WHO recommendations for women in the United States is unclear, as breast feeding, nutrition, maternal age at first birth, and total fertility rate differs substantially between the United States and the low‐ and middle‐resource countries upon which most of the evidence is based. Methods To inform guideline development for birth spacing specific to women in the United States, the Office of Population Affairs ( OPA ) convened an expert work group meeting in Washington, DC , on 14‐15 September 2017 among reproductive, perinatal, paediatric, social, and public health epidemiologists; obstetrician‐gynaecologists; biostatisticians; and experts in evidence synthesis related to women's health. Results Presentations and discussion topics included the methodological quality of existing studies, evaluation of the evidence for causal effects of short interpregnancy intervals on adverse perinatal and maternal health outcomes, good practices for future research, and identification of research gaps and priorities for future work. Conclusions This report provides an overview of the presentations, discussions, and conclusions from the expert work group meeting.