Effects of Doxycycline on Periods

By Adam Cloe Ph.D./M.D. ; Updated July 27, 2017

Doxycycline is a antibiotic that has a variety of side effects, which includes acid reflux and the possibility for an allergic reaction. It can also cause some other very serious side effects, such as permanent yellowing of teeth and, in infants or children, a sudden stoppage of bone growth. As with any antibiotic, the risks of side effects must be balanced with the advantages of using that particular antibiotic.


Doxycycline is an antibiotic that is related to tetracycline. It can be used to treat a variety of infections, including bacterial and certain kinds of parasitic infections. It is often used to treat acne and diseases of the urinary tract and reproductive system. It can also be used prophylactically to prevent malaria.

Doxycycline and the Menstrual Cycle

Doxycycline is often anecdotally reported to interact with the menstrual cycle. Many women report that their period is delayed. This delay can last anywhere from a few days to several weeks. This delay is reported to occur both in women who are sexually active and those who aren't.

Causes of Delayed Periods

The menstrual cycle is very sensitive to hormonal levels. These hormones can be affected by a variety of factors, including nutrition, stress and alterations in the circadian rhythm. While it is possible that doxycycline can interact with hormone levels, the conditions that often warrant doxycycline treatment (infection or malaria prophylaxis) can also lead to stress and dietary changes.

Doxycycline and Oral Contraceptives

Many doctors recommend that patients who are using oral contraceptives utilize another method of birth control while taking doxycycline. This is because doxycycline causes certain enzymes in the liver to become more activated. Because these enzymes also break down oral contraceptives, doxycycline treatment could compromise the effectiveness of these medications. Because oral contraceptives work by controlling hormone levels, any drug that interacts with them could disrupt the hormone cycle.


Clinical studies have determined that doxycycline does not decrease the effectiveness of oral contraceptives. Nevertheless, because of the medication's potential to disrupt the hormonal cycle, many physicians still recommend "backup" contraception for patients taking doxycycline.

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