Social factors and pregnancy weight gain in relation to infant birth weight: a study in public health centers in Rasht, Iran.

OBJECTIVES: This study aimed to examine the relationship between total pregnancy weight gain, maternal educational level, working status and infant birth weight among mothers and infants in urban health centers in Rasht, Iran.

DESIGN: Pregnant women from six different public health centers in urban areas were studied in a prospective design. Data on women's age, parity, level of education, working status, infant birth weight, mothers' height, and prepregnancy weight and total weight gain during pregnancy were collected. The subjects were grouped based on their prepregnancy BMI and according to Institute of Medicine (IOM) recommendation for total pregnancy weight gain. The subjects were also categorized based on their years of schooling as less, intermediately and highly educated. In this study women were considered as either housewives or employed.

SETTING: Public health centers in urban areas in Rasht, Iran.

SUBJECTS: A total of 1914 pregnant women were studied.

RESULTS: These data showed that pregnancy weight gain was not different between women with normal prepregnancy weight and underweight when educational levels and working status were taken into account. Besides, pregnancy weight gain was positively related to the level of education. Analysis of variance showed that infant birth weights were not similar in mothers who gain weight less, within and above recommended ranges. In all, 60% of the normal weight women and 56.7% of the underweight women had weight gain less than the lower cutoffs of IOM recommendation. Results of logistic regression analysis showed that low level of mother's education was the only predictor for low birth weight (LBW) (>12 y education OR = 0.27(0.10-0.69)) and 5-12 y education OR = 0.62 (0.2-0.94).

CONCLUSION: These results showed that pregnancy weight gain lower recommended ranges are highly prevalent in Iranian women in public health centers in urban areas in Rasht. Moreover, mother's level of educational level may be considered as the most important determinant of birth weight and LBW in this population.