Platelet distribution width and the risk of unexplained recurrent pregnancy loss: a meta-analysis.

OBJECTIVE: Changes of platelet distribution width (PDW) have been observed in women with unexplained recurrent pregnancy loss (URPL). However, relevant previous studies showed inconsistent results. We performed a meta-analysis to comprehensively evaluate the association between PDW and URPL.

METHODS: Observational studies reporting the difference of PDW between women with and without URPL were retrieved by searching PubMed, Embase, Web of Science, Wanfang, and CNKI. A random-effect model was used to pool the results by incorporating potential heterogeneity.

RESULTS: Eleven case-control studies with 1847 women with URPL and 2475 healthy women were included. Age was matched for all studies between cases and controls. Pooled results showed women with URPL had significantly increased level of PDW (mean difference [MD]: 1.54%, 95% CI: 1.04 to 2.03, p < 0.05; I2 =77%). Subgroup analysis showed consistent result for URPL defined as ≥ 2 (MD: 1.45%, p = 0.003) and ≥ 3 (MD: 1.61%, p < 0.001) failed clinical pregnancies, and in studies compared to women with normal pregnancy (MD: 2.02%, p < 0.001) and non-pregnant healthy women (MD: 1.34%, p < 0.001). Results of the meta-analysis also showed that increment of PDW was associated with higher odds of URPL (per 1 unit, odds ratio: 1.26, 95% CI: 1.17 to 1.35, p < 0.001; I2 = 0%).

CONCLUSIONS: Women with URPL had significantly increased levels of PDW compared to healthy women without URPL, which suggest that higher PDW may predict the risk of URPL.