[Analysis of the incidence and perinatal outcomes of multiple births in Zhejiang Province from 2008 to 2013].

Objective: To analyze the trends of multiple births rates and their perinatal outcomes in Zhejiang province from 2008 to 2013.

Methods: Data were obtained from hospital-based perinatal mortality surveillance system in Zhejiang, including all the hospitals in 30 monitoring counties (districts). All births (28 or more weeks of gestation) born in the monitoring hospitals were included in our study within 7 days after delivery from 2008 to 2013. Chi-square test was performed for statistical analyses for comparisons between regions. Trends in the incidence of multiple births and causes of perinatal death were analyzed using chi-square test for trend.

Results: From 2008 to 2013, the multiple births rate in Zhejiang province was increased and the rates were 2.32% (5 551/239 636), 2.49% (6 053/243 452), 2.61% (6 549/250 594), 2.82% (7 758/275 105), 2.91% (8 803/302 447) and 3.06% (9 051/295 709), respectively. And the perinatal mortality rates for multiple births were 4.32% (240/5 551), 3.45% (209/6 053), 3.76% (246/6 549), 2.86% (222/7 758), 2.77% (244/8 803) and 2.11% (191/9 051), respectively. A significant drop in the perinatal mortality rates for multiple births was observed between 2008 and 2013 (χ(2) trend = 66.52, P < 0.001). There was a significantly greater risk for perinatal death to multiple births when compared with single birth (OR = 3.62, 95% CI: 3.42-3.83). The three leading causes of perinatal death for multiple births were birth defect, premature and/or low birth weight, and twin-twin transfusion syndrome.

Conclusion: The multiple births rates in Zhejiang province showed an increasing trend. The perinatal mortality rates for multiple births were decreased annually, however, it was still higher than those in developed countries.