[Trend and outcome of multiple pregnancies in Beijing, 1996-2010]

To describe the trend of multiple pregnancies and to compare the results with single pregnancy in Beijing from 1996 to 2010. Prevalence rates of pregnancy complications were compared between multiple and single pregnancies.

In 1996, 1997, 1998, 1999, 2000, 2005, 2010, live births in two hospitals in Beijing were included to describe the trend of multiple and single pregnancy. Case-retrospective analyses were used. Information was collected, including maternal age, fetus number, delivery mode, with/without pregnancy induced diseases as hypertension, diabetes or anemia, gender of the baby, birth-weight and gestation etc. Linear regression analyses were applied to assess the trend of birth-weight and the rates of prevalence.

63 661 babies and 62 895 puerperal were involved in this study. From 1996 to 2010, prevalence of multiple pregnancies increased by 0.02%, prevalence of cesarean delivery among multiple pregnancy women increased by 2.25% and the proportion of women older than 30 years increased by 3.52% and 2.89% among multiple or single pregnancy women, annually. However, the birth-weight did not show obvious change in both multiple and single birth babies. No obvious change was observed in the prevalence of low birth weight. Prevalence rates of premature birth increased by 1.62% and 0.16% among multiple and single pregnancy women, annually. From 1996 to 2010, the mean values of birth-weight among single birth babies were larger than 3 250 grams and under 2 500 gram among multiple birth babies. Rates of prevalence on pregnancy induced hypertension and anemia were higher in multiple pregnancy women than in single pregnancy women. Differences of rates on prevalence rates of pregnancy diabetes between multiple and single pregnancy women were not statistically significant.

Prevalence of multiple pregnancies increased from 1995 to 2010 in Beijing. Mothers of multiples were more likely to get pregnancy complication than the single pregnancy women.