Brain region smaller in birth control pill users

Researchers have found that women taking oral contraceptives, commonly known as birth control pills, had significantly smaller hypothalamus volume, compared to women not taking the pill. Located at the base of the brain above the pituitary gland, the hypothalamus produces hormones and helps regulate essential bodily functions including body temperature, mood, appetite, sex drive, sleep cycles and heart rate.

Structural effects of sex hormones on the human hypothalamus have never been reported, according to the researchers. This may be in part because validated methods to quantitatively analyse MRI exams of the hypothalamus have not been available.

"There is a lack of research on the effects of oral contraceptives on this small but essential part of the living human brain. We validated methods for assessing the volume of the hypothalamus and confirm, for the first time, that current oral contraceptive pill usage is associated with smaller hypothalamic volume," said a researcher.

Oral contraceptives are among the most popular forms of birth control and are also used to treat a host of conditions, including irregular menstruation, cramps, acne.

According to a 2018 report from the Centers for Disease Control and Prevention's National Center for Health Statistics 47 million women aged 15-49 in US reported current use of contraceptives. Of those, 12.6 per cent used the pill.

For this study, researchers recruited 50 healthy women, including 21 women who were taking oral contraceptives. All 50 women underwent brain MRI

"We found a dramatic difference in the size of the brain structures between women who were taking oral contraceptives and those who were not," Lipton said.