Meta-analysis of associations between maternal breast cancer and the risk of adverse delivery outcomes

Background: Research into the effects of breast cancer on delivery outcomes has generated inconsistent findings.

Objectives: To pool data from existing observational studies of the effect of breast cancer on preterm delivery and low delivery weight.

Search strategy: A systematic literature search of PubMed, Embase, and Web of Science databases using keywords including, "breast cancer" and "birth outcome" up to March 7, 2017, was performed.

Selection criteria: Observational studies of the effect of breast cancer on delivery outcomes were included.

Data collection and analysis: Articles were reviewed independently by two authors and data were extracted. Risk ratios and 95% confidence intervals were calculated.

Main results: Preterm delivery data were included from seven studies including 6 687 579 patients and low delivery weight data were retrieved from five studies including 6 687 103 patients. Maternal breast cancer was associated with an increased risk of preterm delivery (pooled risk ratio 1.82, 95% confidence interval 1.44-2.30) and low delivery weight (pooled risk ratio 1.41, 95% confidence interval 1.15-1.74). No publication bias was detected in the meta-analysis.

Conclusions: The present meta-analysis demonstrated that maternal breast cancer was associated with increased risk of preterm delivery and low delivery weight.