New Zealand’s Chief Science Advisor has recommended weight loss interventions be made available to women planning a pregnancy. In a postpartum survey of 723 New Zealand women, 44% of all pregnancies were unplanned, and in multivariate analysis, younger women, women with less income, women with higher parity, and single women were more likely to have an unplanned pregnancy (all P ≤ 0.002). In addition, three‐quarters of pregnancies to indigenous Māori and Pacific women were unplanned. In conclusion, New Zealand women known to have the highest rates of overweight and obesity were also most likely to have unplanned pregnancies, thereby preventing their access to any forthcoming preconception weight loss programs.