Increased Breastfeeding Frequency Enhances Milk Production and Infant Weight Gain: Correlation with the Basal Maternal Prolactin Level.

Abstract

Background: Breastfeeding is an important health concern for postpartum women. Objective: This study aimed to investigate the effect of breastfeeding frequency on the level of serum prolactin (PRL), milk intake, and infant weight gain. Materials and Methods: The time and duration of each breastfeeding episode were recorded by participants from day 1 to 28 postpartum. According to their diaries, we divided participants into the low-frequency breastfeeding group (Group I; <10 breastfeeding episodes/day) and high-frequency breastfeeding group (Group II; >/ = 10 breastfeeding episodes/day). A total of 23 mother-infant pairs were enrolled; blood samples were drawn between 1600 and 1800 hours. The PRL levels were examined using the DPC Immulite system. Results: Overall, 71.8% (23) of the enrolled mother-infant pairs completed the follow-up. Infant birth weight was higher in Group II than in Group I (3275.6 ± 93.3 g versus 2918 ± 82.1 g). On day 28 postpartum, infants in Group II ingested significantly more milk per feeding (71.6 ± 4.0 mL versus 54.1 ± 5.2 mL) and gained more weight from birth (142.9% ± 4.5% versus 130.2% ± 2.4%) compared with those in Group I. The mothers of Group II had significantly higher basal serum PRL levels (116.4 ± 11.8 ng/mL versus 72.7 ± 7.77 ng/mL), but a significantly lower increase in PRL postsuckling (168.5% ± 23.1% versus 291.6% ± 37.6% of basal PRL). The frequency of suckling was positively correlated (r = 0.5) with the basal PRL level. Moreover, infant weight gain was significantly higher in male (144.7% ± 4.7%) than in female (132.3% ± 2.9%) infants. Conclusions: Increase in frequency of breastfeeding of over 10/day is associated with baseline PRL levels and increased milk production and weight gain. These results provide useful information for breastfeeding women.