Health outcomes of maternal smoking during pregnancy and postpartum period for the mother and infant: protocol for an umbrella review

BACKGROUND: Internationally, tobacco smoking is a leading cause of mortality, morbidity and health inequality. In England, despite increasing awareness about importance of public health interventions to reduce smoking, about 10% of pregnant women are known to be smokers at the time of delivery. There are many systematic reviews investigating the impact of maternal smoking during pregnancy on particular health conditions. Hence, this overview of systematic reviews, which aims to include all health conditions for mother and infant caused by smoking during pregnancy, is timely. METHODS: CINAHL, EMBASE, MEDLINE, PsycINFO, Web of Science, CRD Database (includes DARE, NHSEED and HTA) and HMIC databases will be searched for systematic reviews investigating the effects of smoking during pregnancy. Only reviews written in English and published by 31/12/17 will be included. Studies focussed on low-income countries will be excluded. Study selection and quality assessment will be completed by two reviewers independently. To assess the quality of included studies, the Centre for Reviews and Dissemination checklist for systematic reviews will be utilised. DISCUSSION: Existing systematic reviews focus on the impact of smoking during pregnancy on a specific health condition. This review aims to analyse current evidence on the overall health outcomes associated with smoking whilst pregnant by providing an overview of evidence from systematic reviews. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018086350. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13643-018-0900-9) contains supplementary material, which is available to authorized users.