Differences in the incidence and characteristics of BDs
between singleton and multiple births
A total of 53,196 births between 2012 and 2018 that were associated with
BDs were included in the analysis, of which 49,872 were singletons and
3,324 were multiple births (Table 1). The mean incidence of BD for
multiple births was 109.99 per 1,000 births, which was significantly
higher than that for singleton births (26.29 per 1,000 births;
χ2=7600, P <0.001). Significant
differences were also found between singleton and multiple births
associated with BDs with respect to mean maternal age, the distribution
of maternal age group, maternal domicile, maternal education, maternal
parity, and infant sex (all P <0.05). Compared
with women who had singletons with
BDs, those who had multiple pregnancies associated with BDs were more
likely to be older, live in an urban environment, have a college-level
education or above, and be multiparous.