Categorized | Women's hair loss

Do birth control pills induce hair loss?

hormonal contraceptionHormonal contraception, which includes birth control pills, is one of the most widespread and effective methods that helps prevent unwanted pregnancies. However, this type of contraception may provoke some side effects, including hair loss.

How do birth control pills affect our hair?

To answer this question we should first take a look into the female reproductive physiology and the action of these preparations.

At the beginning of every menstrual cycle, the level of estrogen starts rising gradually. The increasing amount of estrogen creates ‘sperm-friendly’ cervical mucus and makes sure that the lining of the uterus is being filled with blood and nutrients. On average, a mature egg is released from the ovary on the 14th day of the cycle and this is called ovulation. Right after ovulation, the level of progesterone (another female sex hormone) starts increasing in order to continue to build up the uterine lining to prepare for a fertilized egg. If conception does not happen, the levels of both estrogen and progesterone drop. Without the high levels of these two hormones, the thickened lining of the uterus breaks down and sheds and this is menstruation.

Oral contraceptives

There are two main types of birth control pills:

  • Combination birth control pills– these contain both estradiol (an estrogen) and progestin (synthetic form of progesterone). The combination of estradiol and progestin hormones entering the female body by way of such contraceptive pills interferes in the reproductive process and imitates the natural changes in the blood levels of both hormones. They suppress ovulation and do not allow egg cells to develop and leave the ovaries, thicken cervical mucus making the neck of the uterus impervious to the sperm and change the endometrium in such a way as to not allow fertilized eggs to attach to the uterine wall.
  • Minipills – these contain only progestin, The dose of this hormone is usually lower than in combination birth control pills. These pills do not always suppress ovulation, but they affect the cervical mucus and prevent a fertilized egg from being implanted in the wall of the uterus.

Hormones affect all the processes happening in the human body and hair follicles which grow hair are not an exception. The hormones entering the body with birth control pills can affect the lifecycle of hair follicles – either by shortening the life cycle or by lengthening the cycle.

Types of hair loss induced by birth control pills.

Oral contraceptives can provoke hair loss in females by 2 different mechanisms – by facilitating androgenetic alopecia in those women who are genetically predisposed to hair loss and by drug-induced hair loss (a special case of telogen effluvium)1:

  • Androgenetic Alopecia. This is a genetic condition that develops in those women whose hair follicles are hypersensitive to a certain androgen (dihydrotestosterone or DHT) converted from testosterone. The hair follicles degrade under the influence of DHT and start producing thin and weak hair and gradually the follicles lose the ability to grow any hair at all. Usually the levels of androgens in females are rather low and the natural levels of estrogens can protect the follicles from the harmful effect of DHT. But, progestins contained in various birth control pills may have androgenic activity in varying degrees. So, if a woman who is genetically predisposed to alopecia starts taking oral contraceptives that contain the type of progestin with high androgenic activity, then she may experience either the onset of considerable hair loss or the intensification of the existing problem.
  • Telogen Effluvium. The life cycle of each hair follicle consists of 3 phases – growing (anagen), transitional (catagen) and resting (telogen). At the end of the latter, the hair falls out naturally and the follicle enters the growing phase again. Usually only 10% of follicles are in telogen phase simultaneously. Telogen Effluvium is diagnosed when hair follicles prematurely shift from the growing to the resting phase. In Telogen Effluvium, up to 50% of the hair follicles can be in resting phase at the same time. With the use of oral contraceptives, Telogen Effluvium hair loss can happen 2-3 months after the cessation of such pills. Estrogen in birth control pills can prolong the anagen phase of the hair follicle and so some women may even experience thicker and stronger hair when on oral contraceptives. But once these pills are not taken any more, those hair follicles that have been in the prolonged growing phase now enter telogen and consequently shed the hair. As a rule, it takes from 2 to 6 months for those women who have faced hair loss after the cessation of birth control pills to fully recover without specific therapy.

Despite all the above, some oral contraceptives with high estrogen levels and anti-androgenic effect can be administered in women with low levels of estrogen and predisposition to alopecia in order to stop hair thinning and shedding.

Alopecia induced by hormonal contraceptives is not a newly discovered condition. The first cases were reported back in 1965-1968. So, there are general recommendations for women who are going to start or are already taking birth control pills:

  1. Study your family history. If anyone from your family has ever suffered from androgenetic alopecia, then probably you are predisposed to this type of alopecia as well. In such cases, it is worth avoiding hormonal contraceptives and giving preferences to other non-hormonal methods of contraception, such as using condoms, spermicidal preparations, etc. If genetic causes of hair loss are detected, then you should seek professional advice from dermatologist or trichologist.
  2. The American Hair Loss Association recommends avoiding those birth control pills or other hormonal contraceptive preparations that are known to contain high levels of hormones with increased androgenic activity and use only oral contraceptive pills with a low-androgen index with low androgenic activity.
  3. If hair loss has started after you stopped taking your birth control pills, then either resume the intake or wait until your hormone levels settle down and the hair growth starts on its own.
  4. If your hair loss has started when you switched from one oral contraceptive to another, you should consult with your gynecologist and either return to the use of the first drug or find a third one that won’t cause such a side effect.

Conclusion

Up until now, the understanding of alopecia mechanisms remains vague. Trichologists are quite united in the opinion that women with predisposition to alopecia should avoid birth control pills containing high levels of androgenic progestins.

Also there are some researches which show that certain progestins can inhibit the activity of the 5 alpha-reductase enzyme which converts testosterone into dihydrotestosterone, and thus, can potentially help cope with androgenetic alopecia.2 Other studies claim that oral contraceptives can diminish the level of free or bioavailable testosterone.3 So the lower the level of free testosterone, the lower the level of the converted dihydrotestosterone which is the main culprit of androgenetic alopecia. Some birth control pills with anti-androgenic activity and high levels of estrogen can be used as a part of alopecia therapy. Whereas others with a high androgen index can promote the hair loss process.

One thing is obvious, whether or not you have any hair loss problems or genetic predisposition to alopecia, you can take birth control pills only if they are approved for you by your gynecologist.

References:

  1. Alopecia: A Practical Approach to Diagnosis and Management (Ivan Jen, Can Fam Physician. Mar 1980; 26: 410–414.) http://pubmedcentralcanada.ca/picrender.cgi?accid=PMC2383562&blobtype=pdf
  2. Inhibition of skin 5 alpha-reductase by oral contraceptive progestins in vitro. (Rabe T, Kowald A, Ortmann J, Rehberger-Schneider S.; Gynecol Endocrinol. 2000 Aug;14(4):223-30.) http://www.ncbi.nlm.nih.gov/pubmed/11075290
  3. The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis. (Zimmerman Y, Eijkemans MJ, Coelingh Bennink HJ, Blankenstein MA, Fauser BC.; Hum Reprod Update. 2014 Jan-Feb;20(1):76-105) http://www.ncbi.nlm.nih.gov/pubmed/24082040