[Multiple birth trends in the region of Castilla y León (Spain) in a 13 year period].

Introduction: Multiple pregnancy has increased in prevalence in the last few years, which could lead to more foetal and maternal morbidity issues. The aim of this study is to describe the trend of multiple pregnancy deliveries in Castilla y León during the last 13years and the subsequent impact on foetal and maternal health.

Material And Methods: Data was collected from the hospital discharge reports registered in the Regional Health-care database (SACYL: Health care in Castilla y León) between 2001 and 2013. A cross sectional descriptive study was conducted, including trend analysis with log-linear joint point model, a rhythm metric study, as well as a risk assessment with multivariate analysis.

Results: A pronounced upward trend was observed in the proportion of multiple deliveries in this time period, compared to single ones, with an annual percentage change of 3.4% (95% CI: 2.5-4.4). Multiple pregnancy was significantly correlated with advanced maternal age, abnormal glucose tolerance, dystocia and caesarean section delivery, premature birth, foetal malposition, foetal macrosomia, stillbirth, in vitro fertilisation, and hypertensive episodes of pregnancy. In vitro fertilization showed a 9.3 fold increased risk in multiple pregnancy (95% CI: 7.4-11.5), with maternal age increasing the risk up to 5% per year of age (OR: 1.05: 95%CI: 1.04-1.05). No seasonal rhythm was observed in multiple deliveries compared with single ones.

Conclusion: Multiple pregnancy has experienced a continuous increase, with no seasonal trend, and is associated with the increase in assisted reproductive technology and advanced maternal age. This involves more problems regarding foetal and maternal morbidity and mortality.