Efficacy of fennel and combined oral contraceptive on depot medroxyprogesterone acetate-induced amenorrhea: a randomized placebo-controlled trial

Abstract

ObjectivesWe aimed to determine the efficacy of fennel and low-dose combined oral contraceptive (LD-COC) on inducing menstrual bleeding and method continuation in women using depot medroxyprogesterone acetate (DMPA) who had no menstrual bleeding within the previous 45 to 140 days. Study designIn this double-blind double-dummy trial, 78 married women referred to public health centers in Hamadan, Iran, who complained of menstrual cessation induced by DMPA were randomly assigned into fennel, LD-COC or placebo groups with an allocation ratio of 1:1:1. All participants received two fennel or placebo capsules and one placebo or LD-COC pill daily for 21 days. We evaluated menstrual bleeding using the Higham pictorial chart within 40 days following initiating intervention. Data were analyzed using chi-square or analysis of variance. ResultsThere was no loss to follow-up. Significantly more women in the fennel (73%) and LD-COC (81%) groups experienced menstrual bleeding compared to the placebo (19%) group [relative risk (RR) 3.1, 95% confidence interval (CI) 1.6 to 6.2; RR 4.2, 95% CI 1.9 to 9.4, respectively]. Mean amount of menstrual bleeding among those who experienced menstruation was significantly higher in the fennel group (21 cc) than both the LD-COC (14 cc) and placebo (12 cc) groups. Also, women using fennel (73%) and LD-COC (65%) were significantly more likely than those using placebo (31%) to have subsequent DMPA injection [RR 2.5 (95% CI 1.3 to 4.9) and RR 2.0 (95% CI 1.1 to 3.7), respectively]. ConclusionsFennel and LD-COC can resolve DMPA-induced amenorrhea and increase continuation rate of this contraceptive method.