Beliefs and Norms Associated with the Use of Ultra-Processed Commercial Milk Formulas for Pregnant Women in Vietnam.

Commercial milk formula for pregnant women (CMF-PW) is an expensive, ultra-processed food with a high concentration of sugar, the consumption of which may be linked to negative health outcomes. However, CMF-PWs are promoted as beneficial for pregnant women and lactating mothers as well as their children. To date, little is known about the factors associated with the use of CMF-PW among pregnant women. We performed this analysis to examine the association between the use of CMF-PW and related beliefs and norms among pregnant women in Vietnam. We interviewed 268 pregnant women in their second and third trimesters from two provinces and one municipality representing diverse communities in Vietnam. Multinomial (polytomous) logistic regression, structural equation modeling (SEM), and propensity score matching (PSM) analysis were used to examine associations between beliefs and social norms related to CMF-PW and reported consumption, characterized as occasional, recent, and never during the current pregnancy. Overall, 64.6% of pregnant women reported using CMF-PW during the current pregnancy and 34.7% consumed CMF-PW on the day prior to the interview. Strong beliefs that CMF-PW will make a child smart and healthy (53.7%) and the perception that use of CMF-PW is common (70.9%) were associated with increased use on the previous day (beliefs: aOR: 3.56; 95% Confidence Interval (95% CI): 1.65, 7.71; < 0.01 and social norms aOR: 2.29; 95% CI: 1.13, 4.66; < 0.05). SEM and PSM analyses confirmed these findings for both occasional and regular CMF-PW use. Results are consistent with observations of CMF-PW product labels and marketing tactics in Vietnam. The prevalent use of CMF-PW in Vietnam is associated with the belief that these products make children smart and healthy and the perceived social norm that most mothers use these products, which mirrors marketing messages and approaches employed by the CMF industry.