Background Sickle cell disease (SCD) is a multisystem disease characterised by vaso-occlusive crisis, chronic anaemia and a shorter lifespan. More patients with SCD are living till reproductive age and contemplating pregnancy. Pulmonary complications in pregnancy are significant causes of maternal morbidity and mortality but yet this has not been systematically quantified. A systematic review and meta-analysis were conducted to quantify the association between SCD and pulmonary complications in pregnancy.

Methods MEDLINE, EMBASE, Web of Science, Cochrane and Maternity and Infant Care databases were searched for publications between January 1998 and April 2019. Observational studies involving at least 30 participants were included. Random-effects models were used for statistical meta-analysis.

Findings Twenty-two studies were included in the systematic review and 18 in the quantitative analysis. The meta-analysis included 3964 pregnancies with SCD and 336 559 controls. Compared with women without SCD, pregnancies complicated by SCD were at increased risk of pulmonary thromboembolism (relative risk (RR) 7.74; 95% CI 4.65 to 12.89). The estimated prevalence of acute chest syndrome and pneumonia was 6.46% (95% CI 4.66% to 8.25%), with no significant difference between the HbSS and HbSC genotypes (RR 1.42; 95% CI 0.90 to 2.23).

Interpretation This meta-analysis highlighted a strong association between SCD and maternal pulmonary complications. Understanding the risks of and the factors associated with pulmonary complications would aid preconceptual counselling and optimal management of the condition in pregnancy, thereby reducing associated maternal morbidity and mortality.

PROSPERO registration number CRD42019124708.