JUN 03, 2024 9:00 AM PDT

Synthetic Estrogen Linked to Increased Anxiety in Female Rats

WRITTEN BY: Annie Lennon

Female rats given synthetic estrogen found in birth control exhibited more anxiety-like behaviors than those given natural estrogen. The corresponding study was presented at the Endocrine Society's annual meeting, ENDO 2024

According to the CDC, 12.6% of women aged between 15 and 49 years old in the US use oral contraceptive pills. Types of contraceptive pills include combined oral contraceptives, which contain a combination of estrogen and progestin, and progestin-only pills. 

Some women stop taking birth control pills due to behavioral side effects. Alesia Prakapenka, Ph.D., an assistant professor in the Biomedical Sciences program at Midwestern University, said in a press release: "It is plausible that estrogen type is a key player in mood or cognitive related side effects of hormone-based contraceptive use."

In the current study, researchers investigated how natural and synthetic varieties of estrogen influence cognition and behaviors like anxiety. To do so, they conducted an experiment with 36 young adult female rats aged 3- 4 months old. The rats were given one of the following: synthetic ethinylestradiol plus dienogest, natural estradiol plus dienogest, or a vehicle control treatment. 

Four weeks later, the researchers tested the rats' spatial memory and anxiety-like behavior. They also gathered blood samples form the the rats to assess for levels of estradiol, progesterone, androtenedione and testosterone levels via liquid chromatography-mass spectrometry. 

Ultimately, they found that female rats treated with synthetic estrogen displayed more anxiety-like behaviors than those who received the control substance or natural estrogen. Spatial memory was similar among all the groups. 

"Altogether, our findings support the notion that estrogen type matters for behavioral outcomes associated with contraceptive use, identifying estrogen type as a potential clinical tool for management of behavioral side effects in females," said Abigail Hegwood, M.S., from the Prakapenka Lab at Midwestern University, in a press release


Sources: Neuroscience News

About the Author
Bachelor's (BA/BS/Other)
Annie Lennon is a writer whose work also appears in Medical News Today, Psych Central, Psychology Today, and other outlets.
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