Nutrient intakes during pregnancy: the influence of smoking status and age

To examine the relation of antioxidant and other nutrient intakes in pregnancy to smoking and sociodemographic variables.

Cohort study.

St Mary's Maternity Hospital, Portsmouth.

Pregnant nulliparous women, with no existing complications of pregnancy, were recruited from antenatal booking clinics. A total of 774 women completed seven day food diaries, and supplied detailed data on their use of nutrient supplements.

Smokers had lower intakes of most micronutrients. After adjustment for the confounding effects of maternal age, height, and education, only vitamin C and carotenoid intakes remained significantly depressed. Age was strongly and significantly associated with the intake of most nutrients, including antioxidants, and this association was independent of other maternal factors. Antioxidant intake was therefore lowest in young women who smoked: for example smokers under 24 years had a mean vitamin C intake of 57 mg (SD 35) compared with 106 mg (SD 52) for non-smokers aged 28 and over (difference 49 mg, 95% CI 39, 59). The corresponding intakes of carotenoid equivalents were 1335 micrograms (SD 982) and 2093 micrograms (SD 1283) (difference 758 micrograms, 95% CI 496, 1020).

The study has identified, for the first time, young pregnant women as a group at particular risk of low micronutrient intake. The health implications of poor nutrition now need to be evaluated, particularly for those women who smoke.