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Meta-Analysis
. 2019 Jul 2;16(7):e1002838.
doi: 10.1371/journal.pmed.1002838. eCollection 2019 Jul.

Risks of stillbirth and neonatal death with advancing gestation at term: A systematic review and meta-analysis of cohort studies of 15 million pregnancies

Javaid Muglu  1 , Henna Rather  2 , David Arroyo-Manzano  3 , Sohinee Bhattacharya  4 , Imelda Balchin  5 , Asma Khalil  6 , Basky Thilaganathan  6   7 , Khalid S Khan  8 , Javier Zamora  3   8 , Shakila Thangaratinam  8   9
Affiliations
Meta-Analysis

Risks of stillbirth and neonatal death with advancing gestation at term: A systematic review and meta-analysis of cohort studies of 15 million pregnancies

Javaid Muglu et al. PLoS Med. .

Abstract

Background: Despite advances in healthcare, stillbirth rates remain relatively unchanged. We conducted a systematic review to quantify the risks of stillbirth and neonatal death at term (from 37 weeks gestation) according to gestational age.

Methods and findings: We searched the major electronic databases Medline, Embase, and Google Scholar (January 1990-October 2018) without language restrictions. We included cohort studies on term pregnancies that provided estimates of stillbirths or neonatal deaths by gestation week. We estimated the additional weekly risk of stillbirth in term pregnancies that continued versus delivered at various gestational ages. We compared week-specific neonatal mortality rates by gestational age at delivery. We used mixed-effects logistic regression models with random intercepts, and computed risk ratios (RRs), odds ratios (ORs), and 95% confidence intervals (CIs). Thirteen studies (15 million pregnancies, 17,830 stillbirths) were included. All studies were from high-income countries. Four studies provided the risks of stillbirth in mothers of White and Black race, 2 in mothers of White and Asian race, 5 in mothers of White race only, and 2 in mothers of Black race only. The prospective risk of stillbirth increased with gestational age from 0.11 per 1,000 pregnancies at 37 weeks (95% CI 0.07 to 0.15) to 3.18 per 1,000 at 42 weeks (95% CI 1.84 to 4.35). Neonatal mortality increased when pregnancies continued beyond 41 weeks; the risk increased significantly for deliveries at 42 versus 41 weeks gestation (RR 1.87, 95% CI 1.07 to 2.86, p = 0.012). One additional stillbirth occurred for every 1,449 (95% CI 1,237 to 1,747) pregnancies that advanced from 40 to 41 weeks. Limitations include variations in the definition of low-risk pregnancy, the wide time span of the studies, the use of registry-based data, and potential confounders affecting the outcome.

Conclusions: Our findings suggest there is a significant additional risk of stillbirth, with no corresponding reduction in neonatal mortality, when term pregnancies continue to 41 weeks compared to delivery at 40 weeks.

Systematic review registration: PROSPERO CRD42015013785.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow diagram of study selection in systematic review of prospective risk of stillbirth and neonatal death in pregnancies continued to term.
Fig 2
Fig 2. Risk of bias in studies included in the systematic review on prospective risk of stillbirth and neonatal death in pregnancies continued to term.
Fig 3
Fig 3. Prospective risk of stillbirth per 1,000 pregnancies and risk of neonatal death per 1,000 deliveries by gestational age in pregnancies continued to term.
Stillbirth risk (solid back line); neonatal death risk (solid red line).
See this image and copyright information in PMC

References

    1. Flenady V, Wojcieszek AM, Middleton P, Ellwood D, Erwich JJ, Coory M, et al. Stillbirths: recall to action in high-income countries. Lancet 2016;387:691–702. 10.1016/S0140-6736(15)01020-X - DOI - PubMed
    1. Draper ES, Kurinczuk JJ, Kenyon S, editors. MBRRACE-UK Perinatal Confidential Enquiry: term, singleton, normally formed, antepartum stillbirth. Leicester: University of Leicester Department of Health Sciences Infant Mortality and Morbidity Studies; 2015.
    1. Poon LC, Tan MY, Yerlikaya G, Syngelaki A, Nicolaides KH. Birth weight in live births and stillbirths. Ultrasound Obstet Gynecol. 2016;48:602–6. 10.1002/uog.17287 - DOI - PubMed
    1. Hollis B. Prolonged pregnancy. Curr Opin Obstet Gynecol 2002;14:203–7. - PubMed
    1. Sands. Jeremy Hunt announces new Maternity Safety Strategy in drive to cut stillbirths. London: Sands; 2017 Nov 28 [cited 2019 May 30]. Available from: https://www.uk-sands.org/about-sands/media-centre/news/2017/11/jeremy-hu....