Hormonal Contraception

The purpose of the present study is to characterize the endocrine and metabolic responses to a modest, short-term energy deficiency (\~250 kcal/day) across the menstrual cycle in recreationally active women using different contraceptive methods (oral contraceptive, hormonal IUD, and non-hormonal IUD). This study will leverage daily urinary hormone metabolite tracking and comprehensive metabolic assessments, providing foundational data addressing an important and previously unexamined interaction between energy availability and hormonal regulation in contraceptive users.

The aim of the project is to elucidate the impact of diverse sex hormone profiles on the adaptability of muscle mass to physical training. Additionally, the project aims to investigate secondary effects on adipose tissue, tendons, and other physiological parameters associated with physical function.

The aim of the present study is to investigate the psychosexual effects of combined hormonal contraception regimens, comparing them in terms of estrogen type and dosage, hormonal combination regimen and different routes of administration, in women seeking a hormonal contraception method to prevent unwanted pregnancies. In particular, the study focuses on the incidence of mood disorders and sexual dysfunctions associated with distress in the entire study population using combined hormonal contraception. It will also examine the incidence of these conditions under the influence of specific combined hormonal contraceptives, as well as whether different types of progestins and the route of administration (oral, vaginal or transdermal) may affect the occurrence of mood disorders and sexual dysfunctions.

Oxytocin is a hypothalamic neuropeptide that is best known for its peripheral physiological effects in the female organism i.e., uterine contractions during birth. The neuropeptide furthermore affects reward processing and metabolic functions such as eating behavior and body weight. Oxytocin receptors are present in brain regions associated with the processing of rewards, e.g., ventral tegmental area (VTA), nucleus accumbens (NAcc) and nucleus stria terminalis. Previous studies indicate that oxytocin interacts with sex hormones such as estradiol in a sex-specific manner. Despite known sex differences in oxytocin function, most studies i.e., on the metabolic effects of oxytocin in humans have so far focused on young, healthy men. Intranasal oxytocin administration has emerged as a method to experimentally investigate central nervous effects of oxytocin in the absence of relevant side effects. In the proposed study the investigators aim to systematically investigate the acute effect of intranasal oxytocin on reward processing in relation to circulating and synthetic sex hormones in healthy, naturally cycling women and in women taking hormonal oral contraceptive pills. The investigators will administer 24 international units (IU) of intranasal oxytocin vs. placebo and investigate neural correlates in a 3T MRI scanner including functional imaging during a reward processing task, changes in brain anatomy and connectivity. Additionally, metabolic functions, eating behavior and changes in mood and wellbeing will be assessed and blood will be drawn to assess parameters of hormonal and metabolic status.