Breast-feeding rate comparison by parity and delivery age in Japan

To examine the effects of maternal age on breast-feeding, we classified mothers who delivered vaginally aged 20-42 into 1-year age groups and investigated breast-feeding states. We also studied differences between primiparas and multiparas in breast-feeding.

The subjects were 2,605 primipara mothers (age at delivery ranged from 16to 45 years; the gestational age of their infants ranged from 37 to 42 weeks, birthweight ranged from 2,501 to 4,300 g) and 3,261 multipara mothers (age 18-45 years; the gestational age of their infants ranged from 37-42 weeks, and their birthweight ranged from 2,502-4,726 g) at 12 baby-friendly hospitals in Japan.

The percentage of infants exclusively breast-fed at 1 week and 1 month after birth in the primipara mothers was 80% among mothers in their 20s but lower than 60% among mothers aged above 35. On the other hand, the percentage of infants exclusively breast-fed in the multipara mothers was almost 90% among mothers in their 20s and remained at 70% or over among mothers in their 40s. The percentage of infants exclusively breast-fed was significantly higher in the multipara mothers than in the primipara mothers in many age groups at both 1 week and 1 month of age.

The percentage of infants exclusively breast-fed rate decreased as the maternal age increased. We found that multipara mothers can breast-feed even in their 40s, but primipara mothers may encounter difficulty breast-feeding at ages above 35. Our results suggest a need to consider not only their age but number of children, i.e., breast-feeding experience, to provide effective support to breast-feeding mothers.