Subjects
The recruitment of subjects into the study occurred in 2002. The nulliparous women, most in the 5th to 7th months of pregnancy, were recruited into the study in waiting rooms by one of the authors, during their regular antenatal visits
at the participating teaching (public) hospitals. In the South Australian health system women can have most of their antenatal care with their general practitioner (28% in 2002) or a private obstetrician (34%) (10), attending hospital only on
a few occasions, including to give birth. This limited opportunities for enrolment of such women during antenatal hospital visits and meant that subjects were biased toward women who chose to have their antenatal care predominantly at teaching hospitals.