Public health policy to redress iodine insufficiency in pregnant women may widen sociodemographic disparities.

OBJECTIVE

To evaluate the impact of a mandatory bread fortification programme on estimated iodine intakes of childbearing women and to describe the extent to which uptake of a maternal iodine supplement recommendation is associated with sociodemographic characteristics.

DESIGN

A postpartum survey was conducted using a self-administered questionnaire. Details on pre- and post-conceptional supplement use, bread intake, iodized salt use and maternal sociodemographic and obstetric characteristics were obtained.

SETTING

Eleven maternity wards and hospitals located across New Zealand.

SUBJECTS

Seven hundred and twenty-three postpartum New Zealand women.

RESULTS

Mean iodine intake from fortified bread was 37 μg/d prior to conception. Younger women, women with higher parity, single women and those with unplanned pregnancies were less likely to meet the pregnancy Estimated Average Requirement (EAR) for iodine (all P ≤ 0·022). Although not statistically significant for all months of pregnancy, women with less education and income were less likely to meet the EAR (P ≤ 0·11 and P ≤ 0·2 for all months, respectively) and indigenous Māori women and Pacific women were less likely than New Zealand Europeans to meet the EAR (P ≤ 0·17 and P ≤ 0·051 for all months, respectively). During pregnancy, iodine-containing supplement uptake at the recommended level (150 μg/d) was non-uniform across sociodemographic subgroups, with the most disadvantaged women benefiting the least from this public health policy.

CONCLUSIONS

The disparities in supplement uptake noted here highlight the need for prioritizing further efforts towards universal salt iodization, such as the mandatory fortification of additional processed foods with iodized salt.