Neonatal outcomes
Preterm birth (extremely preterm (+2 SD), 5-min Apgar score below 7, cord blood pH below 7.05 at birth, resuscitation of the newborn, use of a respirator, use of antibiotics, admission to a neonatal intensive care unit, stillbirth (delivery of a stillborn at 22 weeks of gestation or later) and neonatal death (death of a live-born at 0–6 days of age). Demographic factors are presented in table 1. Of these, alcohol or drug misuse during pregnancy (Z72.1– Z72.2), pre-existing diabetes (E10–E12, O24.0–O24.3) and pre-existing hypertension (I10, O10–O11) werederived from the HDR and other variables from the MBR. The area of residence at the time of delivery was divided into urban, densely populated or rural according to national classification by Statistics Finland.26 Prepregnancy body mass index was calculated on the basis of height and weight measures reported by the pregnant women. Adequacy of prenatal care was calculated on the basis of the recommended number of antenatal clinic visits in Finland (13–17 visits in full-term pregnancies)27 adjusted for gestational age at birth. Inadequate prenatal care was defined as attendance at fewer than half of the recommended number of visits.