Recent Australian government policy has encouraged large numbers of women of childbearing age to enter private health insurance. This paper describes how increased uptake of private health insurance may impact on the rate of normal birth, caesarean section and the costs of providing maternity care in low risk primiparous women in New South Wales. A hypothetical model was developed using data from the NSW Midwives Data Collection. Costs were calculated using data established from previous research in NSW (Homer et al 2001). It suggests that, as the proportion of low risk primiparous women with private health insurance increases, the rate of normal birth may decrease with a subsequent increase in rate of caesarean section. As the rate of caesarean section rises, the cost of providing intrapartum and postpartum care may also increase. I argue that increased rates of private health insurance membership have the potential to increase the rate of caesarean section and the cost of providing maternity care to low risk women. It is evident that government policy can impact on the outcome of maternity care in Australia in ways that might not have been predicted. Paradoxically, the care of healthy childbearing women may cost the Australian government more to provide in the future.