Understanding the Birth Control Pill

The first time I heard about the birth control pill was in high school when my friend started taking it for her severe cramps. Back then, I thought that it could just be used for pregnancy prevention! Today I'm breaking down the two types of birth control pills - how they work, side effects, contraindications and potential drug interactions. 

Combination Pills

This pill contains two types of synthetic hormones: ethinylestradiol and progestin. They can either have a 'fixed' dose of both synthetic hormones, or different doses in each pill to mimic the natural phases of the menstrual cycle.

Ethinylestradiol content ranges between 20-40ug, higher doses are given when there are drug interactions causing liver enzyme induction. Whereas lower doses are usually given when a woman's natural fertility is declining.  

There are different types of progestins used such as levonorgestrel, desogestrel, drospirenone and gestodene. Some forms of progestin have been associated with an increased risk of venous thromboembolism. 

How does it work?

The combined pills prevent pregnancy in a couple of different ways:

• Suppressing ovulation, by preventing LH surge

• Preventing follicles from maturing, thus suppressing FSH and LH

• Thickening cervical mucus, thereby preventing sperm movement

• Thinning the endometrial lining, thereby preventing implantation of the egg

Most of these products are available in 21 or 28 (21 days of active medication and 7 days hormone-free) day cycles. This method of contraception has a failure rate of 9%, and with perfect use has a failure rate of 0.3%.

With the combined pill you may notice a decrease in your flow, less period pain, regular periods and fewer PMS symptoms. This is because your true hormones - estrogen and progesterone - are not in charge of your cycle anymore. So, if you went on the combined pill to stop the above symptoms, they'll stop until you stop using the pill. Once you go off the birth control, they may come back! Studies are controversial, but the pills can actually increase breast cancer risk. 

The combined pill has shown a reduction in ovarian and endometrial cancer. 

What are some side effects?

Some side effects to pay attention to are: abdominal pain, chest pain, headaches, eye problems and severe leg pain. Consult your medical doctor if you begin to experience these symptoms.

A 2016 study by the University of Copenhagen studied over 1 MILLION Danish women and investigated the effects of depression and hormonal birth control use. They found that compared to non-users, women taking the combined pill were at a 23% higher risk for depression. Teens (15-19 years old) taking the combined pill had a 80% higher risk for depression.  

A 2013 study, was a review that looked at combined pills and nutritional deficiencies. Folate status may be implicated with the use of the pill, however evidence indicated that levels return to normal after 3 months of pill discontinuation. If a woman plans to become pregnant right after discontinuation, supplementation may be warranted. A decrease in vitamins B2, B6 and B12 was associated with pill use. In addition, Vitamin C levels were lowered in those taking the birth control pill, especially the combined pill as the estrogen may increase Vitamin C metabolism. Vitamin E levels also decreased with combined-pill use. 

Mineral deficiencies were also seen with birth control use. Plasma zinc levels were lower in women taking the combined pill. The pill can also interfere with selenium absorption. Lastly, magnesium can be affected by the pill as it can result in depletion. 

What are their absolute contraindications?

From the Compendium of Therapeutic Choices (2014):

• Breast cancer or hormone-dependent cancer

• Cerebrovascular disease

• Complicated valvular heart disease

• Current or past history of venousthromboembolism or pulmonary embolism

• Diabetes with microvascular complications

• History of, or current myocardial infarction (heart attack) or ischemic heart disease

• Less than 6 weeks postpartum, if breastfeeding

• Migraines with aura at any age

• Hypertension (over 160/100 mmHg)

• Severe cirrhosis or liver tumour

• Smoker over 35 years old

Drug interactions to be aware of

It's not advised that you take St. Johns Wort while taking the pill. You may also experience contraceptive failure if you are concurrently taking certain antibiotic medications. Either refrain from sex at this time, or pair the pill with a condom. Lastly, the combination pill does not protect against STIs, so you may also want to use a condom. 

Mini-pills

These pills contain progestin only, and are an alternative if a woman cannot take exogenous estrogens. 

How does it work?

Progestin-only pills reduce or prevent ovulation (in 60-80% of cycles), prevent sperm from entering the cervix, and thins the endometrial lining, thereby preventing implantation of the egg. Progestin-only pills need to be taking regularly and consistently because their effects can decrease after 22 hours. Manufacturers, recommend a backup method (ie. condom) during their first month of use. 

For postpartum women who are breastfeeding, the Canadian Contraception Consensus guidelines recommend progestin-only methods because there is a decreased risk of blood clots. They also have a neutral effect on milk supply.

This method of contraception has a failure rate of 9%, and with perfect use has a failure rate of 0.3%. 

What are some side effects?

They have a higher incidence of ectopic pregnancy (fertilized egg implants somewhere other than the uterus) and irregular bleeding. A 2016 study by the University of Copenhagen studied over 1 MILLION Danish women and investigated the effects of depression and hormonal birth control use. They found that compared to non-users, women taking the progestin-only pill were at a 34% higher risk for depression. Teens (15-19 years old) taking progestin-only pills had a 120% higher risk for depression.  

What are their absolute contraindications?

From the Compendium of Therapeutic Choices (2014):

• Pregnancy

• Current diagnosis of breast cancer

Drug interactions to be aware of 

Skip taking St. John's Wort, even if if you are experiencing depressive symptoms. For the progestin-only pill, antibiotics don't seem to have an effect on the efficacy. That said, a backup method may be warranted if you are taking them. 

Final Thoughts

Birth control pills can have significant effects on the body, aside from preventing pregnancy. If you're on either a combined or progestin-only pill you may want to speak to your Medical or Naturopathic Doctor about nutrient deficiencies as well as the risk of depression. 

If you found this information helpful, check out my handy chart of the nutritional deficiencies caused by the pill!

References

Palmerley, M., Saraceno, A., Vaiarelli A, Carlomagno G. (2013). Oral contraceptives and changes in nutritional requirements. Eur Rev Med Pharmacol Sci. Jul;17(13):1804-13.

Scholes, D., Ichikawa, L., LaCroix, A., Spangler, L., Beasley, J., Reed, S. and Ott, S. (2010). Oral contraceptive use and bone density in adolescent and young adult women. Contraception, 81(1), pp.35-40.

Skovlund, C., Mørch, L., Kessing, L. and Lidegaard, Ø. (2016). Association of Hormonal Contraception With Depression. JAMA Psychiatry, 73(11), p.1154.

Webberley, H. and Mann, M. (2006). Oral Contraception. Women's Health Medicine, 3(6), pp.262-268.