Association between chorionicity and preterm birth in twin pregnancies: a systematic review involving 29 864 twin pregnancies

S Marleen; C Dias; R Nandasena; R MacGregor; J Allotey; J Aquilina; A Khalil; S Thangaratinam

doi:10.1111/1471-0528.16479

Association between chorionicity and preterm birth in twin pregnancies: a systematic review involving 29 864 twin pregnancies

BJOG. 2021 Apr;128(5):788-796. doi: 10.1111/1471-0528.16479. Epub 2020 Oct 7.

Authors

S Marleen^{1

2}, C Dias², R Nandasena², R MacGregor³, J Allotey⁴, J Aquilina³, A Khalil^{5

6}, S Thangaratinam⁷

Affiliations

¹ Barts Research Centre for Women's Health (BARC), Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
² Sri Jayewardenepura Postgraduate Teaching Hospital, Nugegoda, Sri Lanka.
³ Royal London Hospital, Barts Health NHS Trust, London, UK.
⁴ Institute of Applied Health Research, University of Birmingham, Birmingham, UK.
⁵ St George's University Hospitals NHS Foundation Trust, London, UK.
⁶ Molecular and Clinical Sciences Research Institute, St George's Medical School, University of London, London, UK.
⁷ World Health Organization (WHO) Collaborating Centre for Global Women's Health, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.

PMID: 32888235
DOI: 10.1111/1471-0528.16479

Abstract

Background: The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm birth in twin pregnancies, no systematic review exists evaluating this association.

Objectives: This systematic review was undertaken to assess the association between preterm birth and chorionicity in twin pregnancies.

Search strategy: We searched the electronic databases from January 1990 to July 2019 without language restrictions.

Selection criteria: All studies on twin pregnancies where chorionicity and preterm birth were evaluated were included.

Data collection and analysis: Findings are reported as odds ratios with 95% confidence intervals. The estimates are pooled using random-effects meta-analysis.

Main results: From 13 156 citations, we included 39 studies (29 864 pregnancies). Monochorionicity was significantly associated with increased risk of preterm birth at ≤28, ≤32, ≤34 and <37 weeks in women asymptomatic and symptomatic for preterm labour (odds ratio [OR] 2.14, 95% CI 1.52-3.02, I² = 46%, OR 1.55, 95% CI 1.27-1.89 I² = 68%, OR 1.47, 95% CI 1.27-1.69, I² = 60%, OR 1.66, 95% CI 1.43-1.93, I² = 65%, respectively). Among those asymptomatic for preterm labour, significantly increased odds of preterm birth were seen for monochorionicity at gestations ≤34 weeks (OR 1.85, 95% CI 1.42-2.40, I² = 25%) and <37 weeks (OR 1.75, 95% CI 1.22-2.53, I² = 61%). Sensitivity analysis showed significantly increased odds of spontaneous preterm birth at ≤34 and <37 weeks for monochorionicity (OR 1.25, 95% CI 1.01-1.55, I² = 0% and OR 1.41, 95% CI 1.13-1.78, I² = 0%).

Conclusions: Monochorionicity is significantly associated with preterm birth at all gestations.

Tweetable abstract: In twin pregnancies, monochorionicity is associated with an increased risk of preterm birth at all gestations.

Keywords: Chorionicity; multiple pregnancy; preterm birth; preterm labour; twins; ultrasound predictors.

Publication types

Systematic Review

MeSH terms

Adult
Chorion*
Female
Humans
Pregnancy
Pregnancy, Twin*
Premature Birth / etiology*
Risk Factors
Twins, Dizygotic*
Twins, Monozygotic*