Characteristics (mean ± standard deviation or %) of the entire cohort and the sample used for our analyses.

The sample used for analyses was White parents (for which height data were available) who had their first, singleton child (of which birth weight was available) through a normal vaginal delivery or an emergency Caesarean section. aPHD; Parental height differences (paternal minus maternal height). bOther forms of assistance were: assisted breech delivery, assisted forceps, assisted vacuum extraction, water births and other problems without specification.