Risk of recurrent stillbirth: systematic review and meta-analysis

Abstract

ObjeCtiveTo determine the risk of recurrent stillbirth. DesignSystematic review and meta-analysis of cohort and case-control studies. Data sOurCesEmbase, Medline, Cochrane Library, PubMed, CINAHL, and Scopus searched systematically with no restrictions on date, publication, or language to identify relevant studies. Supplementary efforts included searching relevant internet resources as well as hand searching the reference lists of included studies. Where published information was unclear or inadequate, corresponding authors were contacted for more information.stuDy seleCtiOn Cohort and case-control studies from high income countries were potentially eligible if they investigated the association between stillbirth in an initial pregnancy and risk of stillbirth in a subsequent pregnancy. Stillbirth was defined as fetal death occurring at more than 20 weeks' gestation or a birth weight of at least 400 g. Two reviewers independently screened titles to identify eligible studies based on inclusion and exclusion criteria agreed a priori, extracted data, and assessed the methodological quality using scoring criteria from the critical appraisal skills programme. Random effects meta-analyses were used to combine the results of the included studies. Subgroup analysis was performed on studies that examined unexplained stillbirth. results 13 cohort studies and three case-control studies met the inclusion criteria and were included in the meta-analysis. Data were available on 3 412 079 women with pregnancies beyond 20 weeks duration, of who 3 387 538 (99.3%) had had a previous live birth and 24 541 (0.7%) a stillbirth. A total of 14 283 stillbirths occurred in subsequent pregnancies, 606/24 541 (2.5%) in women with a history of stillbirth and 13 677/3 387 538 (0.4%) among women with no such history (pooled odds ratio 4.83, 95% confidence interval 3.77 to 6.18). 12 studies specifically assessed the risk of stillbirth in second pregnancies. Compared with women who had a live birth in their first pregnancy, those who experienced a stillbirth were almost five times more likely to experience a stillbirth in their second pregnancy (odds ratio 4.77, 95% confidence interval 3.70 to 6.15). The pooled odds ratio using the adjusted effect measures from the primary studies was 3.38 (95% confidence interval 2.61 to 4.38). Four studies examined the risk of recurrent unexplained stillbirth. Methodological differences between these studies precluded pooling the results. COnClusiOnsThe risk of stillbirth in subsequent pregnancies is higher in women who experience a stillbirth in their first pregnancy. This increased risk remained after adjusted analysis. Evidence surrounding the recurrence risk of unexplained stillbirth remains controversial.

Care in subsequent pregnancies following stillbirth: an international survey of parents

“…The risk of stillbirth recurrence in the current study was 2.9%, which is similar to that reported in the systematic review by Lamont et al (2.5%) . Our findings around increased antepartum surveillance are also consistent with previous research .…”

Is it still important to study if ambient air pollution triggers stillbirth?

“…Residual confounding may have also biased the studies reviewed by Siddika et al ,3 as most of the register-based studies were unable to take into account those maternal factors associated with elevated risk of stillbirth, such as obesity, infections, occupation, stress, parity, alcohol, coffee, passive smoking, spontaneous abortions or stillbirth in a previous pregnancy, pre-existing hypertension and diabetes, preeclampsia, eclampsia, placental abruption, premature birth and fetal growth restriction 2 13. To minimise potential bias related to confounding by individual variation in these risk factors and to assess potential effect modification, large prospective cohort studies with detailed information on maternal factors collected from preconception or early in pregnancy are needed.…”

Protecting families from recurrent stillbirth

“…3 This approximately fivefold increase in risk is greater than that of stillbirth associated with pre-existing medical conditions, such as diabetes or hypertension. 4 Heightened antenatal surveillance is recommended in both of these maternal conditions and should be considered for women with a previous stillbirth.…”

“…5-7 Lamont and colleagues were unable to explore the contribution of specific causes of stillbirth to risk in a subsequent pregnancy. 3 If heightened surveillance is recommended for pregnant women with a history of stillbirth, it should be offered to all affected women not just those with an identifiable and potentially recurring cause.…”