Researchers find link between oral contraceptives and blood pressure in women

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Researchers at the Indian Institute of Technology (IIT) Madras and the University of Minnesota are studying the impact of oral contraceptives on blood pressure (BP) in women.

The team identified oral contraceptive use and general fluctuation in oestrogen in women aged 20-25, but that did not influence their BP during lower body exercise and activation of skeletal muscle sensory neurons. In persons with cardiovascular disease, however, they contributed to exaggerated BP response.

The lead investigators of the study are Manda Keller Ross and Miguel Anselmo from the Minnesota University and Ninitha A. J., an assistant professor in the biotechnology department of IIT Madras. Their findings were published in the American Journal of Physiology Regulatory, Integrative and Comparative Physiology. 

Increased sympathetic nerve activity from skeletal muscle sensory neurons during exercise is known as exercise pressor reflex (EPR). This results in increased blood flow from the heart to the skeletal muscle. EPR is greater in men than in premenopausal women and is exaggerated in persons with cardiovascular disease. 

Oestrogens are cardioprotective, reduce sympathetic activity, and increase blood flow to the skeletal muscle through nitric oxide available in the body.

Dr. Ninitha said, women take oral contraceptives to prevent pregnancy, reduce acne, menstrual cramps, and risk of ovarian cysts. She cited a study that found that 70% of women athletes took oral contraceptives at some point in life. “The findings of this study have wide application and are of importance as it sheds light on the influence of oral contraceptives on blood pressure response to exercise in women,” she said.

Dr. Keller Ross said when at around 50 years of age women enter menopause and ovaries stop producing hormones, cardiovascular risk increases. Hence, there is a need to determine whether the use of contraceptive pills is a contributing factor to cardiovascular risk in menopausal females.