The patterns and determinants of birth intervals in multiparous women in Babol, northern Iran

The present study aimed to determine the patterns and factors associated with birth intervals in multiparous women in Babol, northern Iran. We conducted a cross-sectional study of 500 multiparous women at health centers and referred to the hospital for delivery in Babol, northern Iran in 2007. Data were collected using a questionnaire, including birth intervals, demographics, fertility variables, such as maternal education, maternal age at birth, gender of index child, history of still births, child status (infant mortality or still birth) of index child, parity, duration of breast feeding, residence area, contraception method used, and attendance at a family planning clinic. The data were analyzed using a logistic regression model. The mean (+/- SD) birth interval was 61 +/- 25.7 months. In 3.8% of women the birth interval was < 2 years, in 41.7% it was 4-5 years and in 28% it was > or = 6 years. The majority of women (76.8%) were age 20-34 years old at the time of pregnancy. About one-fourth (22.4%) of women were > or = 35 years old at the time of pregnancy and 0.8% of women were < 20 years old at pregnancy. Maternal age, duration of breast feeding, sex of index child, history of still births, history of infant mortality of the index child, type of contraception used, regular attendance at a family planning clinics and parity showed a significant correlation with birth interval (p < 0.05).