Women who drank any alcohol while pregnant were more likely to have an unplanned pregnancy (PAE tier 1: OR 1.89 (95 % CI 1.40–2.55)), smoke (PAE tier 1: OR 1.94 (95 % CI 1.36–2.77)), have a household income of over AUD 100,000 (PAE tier 1: OR 1.71 (95 % CI 1.15–2.54)). They were less likely to perceive the effects of alcohol quickly (PAE tier 1: OR 0.47 (95 % CI 0.37–0.61)), be obese (PAE tier 1: OR 0.53 (95 % CI 0.38–0.75)) or of Asian/other ethnicity (PAE tier 1: OR 0.38 (95 % CI 0.27–0.52)). The PAE tier 2 comparisons revealed that pregnancy planning was only an important factor in those who ceased alcohol consumption in trimester one (PAE tier 2: OR 2.05 (95 % CI 1.47–2.87)), whereas smoking (PAE tier 2: OR 3.05 (95 % CI 2.00–4.67)), higher income (PAE tier 2: OR 2.43 (95 % CI 1.45–4.04)) and obesity (PAE tier 2: OR 0.35 (95 % CI 0.22–0.54)) remained associated only with women who drank throughout.
