Risk of stillbirth, preterm delivery, and fetal growth restriction following exposure in a previous birth: systematic review and meta‐analysis

Background Little is known about the risk of non‐recurrent adverse birth outcomes. Objectives To evaluate the risk of stillbirth, preterm birth (PTB), and small for gestational age (SGA) as a proxy for fetal growth restriction (FGR) following exposure to one or more of these factors in a previous birth. Search strategy We searched MEDLINE, EMBASE, Maternity and Infant Care, and Global Health from inception to 30 November 2016. Selection criteria Studies were included if they investigated the association between stillbirth, PTB, or SGA (as a proxy for FGR) in two subsequent births. Data collection and analysis Meta‐analysis and pooled association presented as odds ratios (ORs) and adjusted odds ratios (aORs). Main results Of the 3399 studies identified, 17 met the inclusion criteria. A PTB or SGA (as a proxy for FGR) infant increased the risk of subsequent stillbirth ((pooled OR 1.70; 95% confidence interval, 95% CI, 1.34–2.16) and (pooled OR 1.98; 95% CI 1.70–2.31), respectively). A combination of exposures, such as a preterm SGA (as a proxy for FGR) birth, doubled the risk of subsequent stillbirth (pooled OR 4.47; 95% CI 2.58–7.76). The risk of stillbirth also varied with prematurity, increasing three‐fold following PTB