[Association between maternal age and adverse pregnancy outcome in twin pregnancy]

To study the association between maternal age and adverse pregnancy outcome in twin pregnancy.

The clinical data of 2 363 women with twin pregnancy from January 2006 to June 2016 were retrospectively reviewed. According to the age, the women were divided into six groups: <20 years (n=15), 20-24 years (n=158), 25-29 years (n=894), 30-34 years (n=936), 35-39 years (n=320), and ≥40 years group (n=40). The above groups were compared in terms of related baseline features and incidence rates of adverse pregnancy outcomes (preterm birth, birth defect, stillbirth in late pregnancy and small-for-gestational-age birth). A generalized estimating equation was used to investigate the risk of adverse pregnancy outcomes in different age groups.

After control for the factors including place of residence, primipara, pregnancy pattern, and gestational diseases, the incidence rates of very preterm birth and moderately preterm birth in the ≥40 years group were 2.60 and 1.99 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of very preterm birth and late preterm birth in the 20-24 years group were 1.99 and 1.33 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of stillbirth in late pregnancy in the <20 years group, the 20-24 years group, and the ≥40 years group were 9.10, 2.88 and 3.97 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of small-for-gestational-age birth in the <20 years group and the 35-39 years group were 2.70 and 0.73 times than those in the 25-29 years group respectively (P<0.05).

In twin pregnancy, pregnant women, aged <20 years, have a higher risk of smaller-for-gestational-age birth and stillbirth in late pregnancy, those aged ≥40 years have a higher risk of very preterm birth, moderately preterm birth and stillbirth in late pregnancy, and those aged 20-24 years have a higher risk of very preterm birth, late preterm birth and stillbirth in late pregnancy.