To study whether the dietary patterns of Finnish pregnant women are associated with their weight gain rate during pregnancy.

A validated 181-item FFQ was applied retrospectively to assess the diet during the eighth month of pregnancy, and maternal height and maternal weight at first and last antenatal visits were recalled. Information on sociodemographic characteristics, parity and smoking of the pregnant women was obtained by a structured questionnaire and from the Finnish Birth Registry. Principal components analysis was used to identify dietary patterns that described the diet of pregnant women based on their food consumption profile.

Finland.

Subjects consisted of 3360 women who had newly delivered in 1997–2002 and whose baby carried human leucocyte antigen-conferred susceptibility to type 1 diabetes in two university hospital regions, Oulu and Tampere, in Finland.

Out of seven dietary patterns identified, the ‘fast food’ pattern was positively associated (β = 0·010, se = 0·003, P = 0·004) and the ‘alcohol and butter’ pattern was inversely associated (β = –0·010, se = 0·003, P < 0·0001) with weight gain rate (kg/week) during pregnancy after adjusting for potential dietary, perinatal and sociodemographic confounding factors. Both of the dietary pattern associations demonstrated dose dependency.

Pregnant women should be guided to have a well-planned, balanced, healthy diet during pregnancy in order to avoid rapid gestational weight gain. The association between diet, health and maternal weight gain of the women who consumed alcohol during pregnancy should be studied further.