Exogenous estradiol and progesterone administration in healthy women does not affect decision making in Iowa gambling task.

Decision-making is based on the integration of various emotional and cognitive processes and is the precondition for planned, structured action. Earlier studies show an increased risk tolerance during fertile phases of the cycle, i.e. the days before ovulation with high estradiol and low progesterone levels. Various studies indicate an influence of the menstrual cycle on decision-making behavior, potentially due to cyclical fluctuations in hormone levels. Estradiol and progesterone in particular can be regarded as the key hormones in cycle regulation. Previous research in humans has primarily been based on self-reported cycle information and correlative relationships. In the described study, we have investigated the influence of an experimental administration of estradiol, progesterone and both hormones in combination in a placebo-controlled, randomized study with young, healthy women (N = 116, mean age 25.7 years). The established and widely used Iowa Gambling Task (IGT) served as the outcome measure. To assess decisions under ambiguity and risk, we separately analyzed task performance in early and late trials of the task. The treatment groups did not differ significantly in either outcome. We discuss the findings against the background of the existing research literature on menstrual cycle and hormone effects as well as specific characteristics of the task and conclude that the previously reported effects are either task or context specific or the hormonal fluctuations of the cycle were not reflected by our manipulation.