The effect of fennel syrup on prolactin levels of blood serum in newly delivered mothers: A triple-blind randomized controlled trial

Background: Prolactin is essential for the production and continued breastfeeding of mothers. In Iran's traditional medicine, a large number of herbal plants including fennel have been reported to increase lactation. Objectives: This study aimed to explore the effect of fennel on prolactin levels of newly delivered mothers. Design: This was a randomized, controlled, triple-blind trial with one-to-one allocation into two groups. Setting: This study was conducted at the Social Security Hospital in Hamadan, IRAN. Participants: Participants included women who had vaginal delivery within 24 hours prior at the maternity hospital, with singleton infants, who weighed above 2500 grams, ≥37 weeks for gestational age, without any risk factors such as hemolysis, sepsis, asphyxia, and jaundice in her newborns. Method: Sixty nine pairs of mother and baby were randomly assigned into intervention (n=35) and control (n=35) groups. Mothers in the intervention group received 3 grams of fennel daily and those in the control group received a placebo. Mother's prolactin levels on the first day and 15 days after administration of fennel and placebo was measured with ELISA device by the research assistant who was blinded to the type of group. SPSS software (version 13) was used to analyze the data. Results: At the beginning of the study, the average mother's prolactin level in the two groups was different, but this difference was not significant. After 15 days of intervention, prolactin level in the intervention and control groups increased compared to its initial value at the beginning of the study and this difference was significant. But after adjusting the amount of prolactin on the 15th day based on the first prolactin, there was no significant difference between the prolactin mean of two groups (P-value=0.76). Conclusion: These finding indicate the use of fennel syrup by mothers for 15 days has no effect on the prolactin level of mother. Although the increase in prolactin levels was observed in other studies, the effect of fennel syrup on prolactin levels has not been confirmed in the early 15^th days after delivery.