Evidence map›Paper›PMID 34280228›Full record

ArticlePloS one2021

Interpregnancy intervals and adverse birth outcomes in high-income countries: An international cohort study.

Gizachew A Tessema, M Luke Marinovich, Siri E Håberg, Mika Gissler, Jonathan A Mayo, Natasha Nassar, Stephen Ball, Ana Pilar Betrán, Amanuel T Gebremedhin, Nick de Klerk and 6 more

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Article in PloS one, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 21 papers, 4 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
21citing papers in PubMed, 4 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

21 citing papers in PubMed, 4 syntheses or guidelines pooled it.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

16 authors.

Gizachew A TessemaCurtin School of Population Health, Curtin University, Perth, Western Australia, Australia.ORCID 0000-0002-4784-8151
M Luke MarinovichCurtin School of Population Health, Curtin University, Perth, Western Australia, Australia.
Siri E HåbergCentre for Fertility and Health (CeFH), Norwegian Institute of Public Health, Oslo, Norway.
Mika GisslerInformation Services Department, Finnish Institute for Health and Welfare, Helsinki, Finland.
Jonathan A MayoDepartment of Pediatrics, March of Dimes Prematurity Research Center, Stanford University, Stanford, CA, United States of America.
Natasha NassarChildren's Hospital at Westmead Clinical School, Faculty of Medicine and Health, University of Sydney, New South Wales, Australia.
Stephen BallCurtin School of Nursing, Curtin University, Perth, Western Australia, Australia.
Ana Pilar BetránUNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland.
Amanuel T GebremedhinCurtin School of Population Health, Curtin University, Perth, Western Australia, Australia.ORCID 0000-0003-2459-1805
Nick de KlerkTelethon Kids Institute, University of Western Australia, Subiaco, Western Australia, Australia.
Maria C MagnusCentre for Fertility and Health (CeFH), Norwegian Institute of Public Health, Oslo, Norway.
Cicely MarstonFaculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom.ORCID 0000-0002-5529-4646
Annette K ReganCurtin School of Population Health, Curtin University, Perth, Western Australia, Australia.
Gary M ShawDepartment of Pediatrics, March of Dimes Prematurity Research Center, Stanford University, Stanford, CA, United States of America.
Amy M PadulaDepartment of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA, United States of America.
Gavin PereiraCurtin School of Population Health, Curtin University, Perth, Western Australia, Australia.ORCID 0000-0003-3740-8117

Funding

Interpregnancy intervals and pregnancy outcomes in CaliforniaR03HD090243 · NICHD · STANFORD UNIVERSITY · PI SHAW, GARY M · 2017 to 2018
$157k
Medical Research Council MC/UU/12013/5Medical Research Council MC_UU_12013/5Medical Research Council MR/M009351/1NICHD NIH HHS R03 HD090243World Health Organization 001
6 · The paper itself

Abstract

backgroundMost evidence for interpregnancy interval (IPI) and adverse birth outcomes come from studies that are prone to incomplete control for confounders that vary between women. Comparing pregnancies to the same women can address this issue.

methodsWe conducted an international longitudinal cohort study of 5,521,211 births to 3,849,193 women from Australia (1980-2016), Finland (1987-2017), Norway (1980-2016) and the United States (California) (1991-2012). IPI was calculated based on the time difference between two dates-the date of birth of the first pregnancy and the date of conception of the next (index) pregnancy. We estimated associations between IPI and preterm birth (PTB), spontaneous PTB, and small-for-gestational age births (SGA) using logistic regression (between-women analyses). We also used conditional logistic regression comparing IPIs and birth outcomes in the same women (within-women analyses). Random effects meta-analysis was used to calculate pooled adjusted odds ratios (aOR).

resultsCompared to an IPI of 18-23 months, there was insufficient evidence for an association between IPI <6 months and overall PTB (aOR 1.08, 95% CI 0.99-1.18) and SGA (aOR 0.99, 95% CI 0.81-1.19), but increased odds of spontaneous PTB (aOR 1.38, 95% CI 1.21-1.57) in the within-women analysis. We observed elevated odds of all birth outcomes associated with IPI ≥60 months. In comparison, between-women analyses showed elevated odds of adverse birth outcomes for <12 month and >24 month IPIs.

conclusionsWe found consistently elevated odds of adverse birth outcomes following long IPIs. IPI shorter than 6 months were associated with elevated risk of spontaneous PTB, but there was insufficient evidence for increased risk of other adverse birth outcomes. Current recommendations of waiting at least 24 months to conceive after a previous pregnancy, may be unnecessarily long in high-income countries.

Indexed as

Birth IntervalsAdultCohort StudiesDeveloped CountriesFemaleHumansInfant, Low Birth WeightInfant, NewbornInfant, Small for Gestational AgeLongitudinal StudiesMaternal AgePregnancyPregnancy OutcomePremature BirthYoung Adult

Identifiers

PMID34280228
PMCPMC8289039

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.