Hormonal contraceptives and gut microbiome

Application of oral combined hormonal contraceptives (CHC) results in a decrease of serum levels of estradiol and progesterone. Since recent studies showed that sex hormones are related to changes in gut microbiota composition, we set out to investigate the effect of CHC on the gut microbiota on a cohort of healthy pre-menopausal women. We analyzed the gut microbiota composition by 16S rRNA gene sequencing from stool samples collected every other day during one menstrual cycle, in parallel with monitoring the serum levels of estradiol and progesterone. Our results show that CHC are related to lower gut microbiota diversity and changed abundance of several genera. This is the first study that shows the effect of CHC on the gut microbiota and calls for further investigation of the underlying mechanisms.Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-1903-9.