Background: To investigate the trends and changes in the incidence and overall outcome of twin pregnancies in Finland, a retrospective study was conducted with emphasis on maternal complications, covering a 28-year study period.
Methods: All 23,498 twin pregnancies with 46,363 live born and 633 stillborn children in Finland during 1987-2014 were included in the study. Data were collected from the national Medical Birth Register and the Care Register on Hospital Care (Finnish Institute for Health and Welfare, Finland) regarding the parturients' characteristics and incidences of several pregnancy and childbirth complications. The incidences of twin pregnancies and maternal complications during pregnancy and childbirth are the main outcome measures of the study. The results are expressed in percentages, means, medians, ranges and standard deviations (SD), when appropriate.
Results: Twins comprised 1.4% of all births in Finland in 1987-2014. Parturients' mean age has remained stable, but the share of over 35 year-old parturients is increasing. The incidences of pre-eclampsia, intrahepatic cholestasis of pregnancy, gestational diabetes and postpartum haemorrhage have risen during the study period. Almost half (44.9%) of twins were born preterm, almost half via Caesarean section (47.1%), and 27.7% of twin labours were induced.
Conclusions: Several pregnancy complications increased during the study period. Advanced maternal age among twin parturients has risen, enhancing the risks for developing complications in a pregnancy already of a high-risk category, and predisposing to preterm delivery. National and international guidelines are necessary to improve the overall outcome of twin pregnancies.
Keywords: Multiple pregnancy; Register data; Twins.