Breast Cancer Prevention Institute
Breast Cancer Prevention Institute
OCD brochure
What smart women know before choosing the Pill

Breast Cancer Prevention Institute


Smart women who take the pill or any hormonal contraception want to be able to weigh the risks and benefits so they can decide what is best for them.

The first thing a woman should know is the efficacy of hormonal contraception. According to the Center for Disease Control, 9 out of 100 women each year who take the Pill faithfully as directed will get pregnant.(1) There is a 6-9% chance of pregnancy over a year with all hormonal contraceptives whether delivered in patches, pills, injections, IUDs or vaginal rings. This is also reflected in abortion statistics. According to the Guttmacher Institute, 17% of women who have abortions were taking hormonal contraception the month they became pregnant.(2)

The second thing a woman should know is how it will affect her health. We all know that all medications will have unwanted side effects and impact our health. Women should know the effects which are serious and even life-threatening as well as more minor effects that may make the Pill “worth the risk.” There are multiple major effects that cause the pill to be potentially lethal.  


Major Side Effects

1 The Pill can cause your blood to clot
These clots can form in your heart, brain, and travel to your lungs from the legs.

2 The Pill can make it easier to get potentially lethal infections
The Pill increases your risk of human papilloma virus (HPV) and human immunodeficiency virus (HIV).

3 The Pill can cause cancer
The Pill is a known group 1 carcinogen for breast, cervical and liver cancers according to the UN’s International Agency on Research of Cancer (IARC).

4 Long-term hormonal contraception was associated with an increase in glioma, a brain cancer.(3)

5 The development of Multiple Sclerosis has been linked to hormonal contraception.(4)

back to top


The Pill can make your blood clot

Blood clots can form in the heart, the brain, or travel to the lungs from the legs.

Blood clots in a heart artery cause a heart attack (MI)

Blood clots in a brain artery cause a stroke (CVA)

Blood clots in your leg veins cause  a deep venous thrombosis (DVT). These blood clots can break off from the legs and go to the lungs causing a fatal pulmonary embolism (PE) and are known as venous thromboembolisms (VTE).

Women with heredity conditions that cause clotting (example: deficiencies in protein C & S, antithrombin III, or Factor V Leiden) cause even higher rates of clotting.

blood clot

back to top

MI: There is twice the risk of heart attack

Women with no conventional risk factors (hypertension, hypercholesterolemia, diabetes, or smoking) who used the Pill had twice the risk of heart attack. The duration of the Pill use did not matter.(5)

  Among women who had used the Pill, the risk of MI was highest among:

Those with hypertension had 5 times the risk.

Those who smoked had over 12 times the risk.

Those who had diabetes had 16 times the risk.

Those who had high cholesterol had 23 times the risk.



CVA: There is over twice the risk of stroke in women on the Pill

  By a meta-analysis which combined the results of 16 studies, there is near 3 times the risk of ischemic stroke in women who used the Pill.

  The risk is even higher with other risk factors. But for women who take birth control pills and smoke, have high blood pressure or have a history of migraine headaches, the stroke risk is significantly higher.(6)

 back to top

VTE: There is two to three times the risk of lung blood clots

The Pill increases the risk of blood clots in the deep veins of women’s legs (DVT). If the blood clots in the legs break off (VTE) and lodge in the lungs, a pulmonary embolism (PE), can lead to death if the PE is large.

By study, oral contraceptives increase the risk of deep venous thrombosis 5 times.(7)

Pulmonary embolism in women who use the Pill for less than a year was tripled compared to women who did not use the Pill.

The risk of pulmonary embolism decreased with decreasing doses of estrogen in the Pill.

Pulmonary embolism increased dramatically by 60-80% if the Pill had androgenic progestins, as found in Yaz and Yasmin, such as desogestrel, gestodene, drospirenone, and cyproterone.(7,8)

The Ortho-Evra patch used for contraception causes clots higher than the rates with the Pill as the patch causes 60% higher estrogen levels than in the Pill users.





Women on the Pill are more likely to develop potentially lethal infections

Women on the pill increased their risk of getting HIV infection by 60% when compared to women not taking the pill.(9)

Women on the pill were twice as likely to transmit HIV to their partner.

Women on the pill were twice as likely to get infected with HPV (human papilloma virus) which causes cervical cancer.(10)


back to top


The Pill can cause breast cancer


Since 1975, the risk of in-situ breast cancer has increased 400% in premenopausal women. Invasive cancers have increased 40% overall in the U.S.

In 2000, the National Toxicology Advisory Panel put estrogen on its list of carcinogens. There are metabolites of estrogen which directly damage DNA causing mutations and cancer.

In 2006, a meta-analysis in the Mayo Clinic Proceedings showed a 44% increase risk of breast cancer in women who took the Pill before having a child.(11)

In 2007, the UN’s International Agency on Research of Cancer (IARC) reported in their Monograph 91 that estrogen-progestin combination drugs (the Pill) were a group 1 carcinogen for breast, cervical and liver cancers.(12) Although the risk of uterine and ovarian cancers were lower on the pill, there is 4 times more breast cancer in women than uterine and ovarian cancers combined.

In 2009, Dolle showed a 320% increase risk of triple negative breast cancer in women on the Pill, which is the most difficult and deadly form of breast cancer to treat.(13)


The Pill can cause cervical cancer

  The risk of cervical cancer increases after more than five years on the Pill.
Women who use the Pill for five to nine years have twice the risk of cervical cancer.
Women who use the Pill for 10 years or more have more than three times risk of cervical cancer.(14)

The Pill can cause liver cancer


  Primary liver cancer (hepatocellular carcinoma) is rare in developed countries and the pill increases its risk over 50% in women.(12)

A meta-analysis of 12 studies showed the Pill increased liver cancer 50%. Six studies showed the longer the Pill is used, the higher the risk.
The pill also increases the risk of benign tumors, hepatic adenomas and focal nodular hyperplasia (FNH) of the liver.

Minor Side Effects

The minor side effects listed below and which are experienced by women on oral contraceptives are the most common. They are not life threatening as are the major side effects, but may impact your sense of well-being.

Weight gain
Decreased libido
Gall bladder disease
Breast tenderness
Mood changes
Inter-menstrual spotting
Vaginal discharge
Visual changes with contact lenses


In conclusion


There are many ways a woman can control her fertility without interfering with her delicately balanced endocrine system and which have less impact on her health. A woman’s menstrual cycle is regulated by the brain’s pituitary gland and hypothalamus. Their hormones secreted in the brain act upon the ovaries in a delicately controlled monthly cycle. Hormonal contraception interferes with this delicate balance that is achieved only when a woman is in good health.

According to the CDC, 88% of US women between 15 and 45 years old, or 61 million women, have used hormonal contraception.(15) When confronted with statistical risks, many women may believe that with low risks, “it won’t happen to me.” Even though the risk of serious side effects is low, when they are taken by millions of women, it results in tens of thousands of women whose health has suffered a major medical event damaging their health. This is reflected in the noticeable increase in very young women with breast cancer. For example, over the last 30 years there has been a 400% increase in non-invasive breast cancers in women under 50.

Major side effects may be life threatening or fatal. Safer options are available. A woman’s fertility may last over 40 years during which time she is exposed to major and minor medical risks of hormonal contraception. As a woman is only fertile about 100 hours a month, or about 4 days, daily exposure to synthetic unnatural hormones may be seen as unnecessary and excessive.

Is it ever worth taking a Group 1 carcinogen to control fertility?

Certainly, mild acne and menstrual cramps can be treated with less dangerous medications. There are other methods which control fertility without putting a woman’s health and life at risk. For instance, natural family planning (NFP) methods have no negative impact on a woman’s health.(16)

Millions of women will get pregnant each year despite properly taking their hormonal contraception.

NFP methods have been shown through research studies to be as effective as the Pill.(17)



Now that you have
the facts,
you can make an informed choice.


References back to top

(1) Effectiveness of family planning methods adapted from World Health Organization (WHO) Department of Reproductive Health and Research, Johns Hopkins Bloomberg School of Public Health/Center for Communication Programs (CCP). Knowledge for health project. Family planning: a global handbook for providers (2011 update). Baltimore, MD; Geneva, Switzerland: CCP and WHO; 2011; and Trussell J. Contraceptive failure in the United States. Contraception 2011;83:397–404.
(2)  Guttmacher Institute. Induced abortion in the United States. July 2014. Available at:
(3) van Hylckama Vlieg A, et al. Venous thrombotic risk of oral contraceptives, effects of oestrogen does and progestogen type: results of the MEGA case-control study. BMJ 2009;339 doi: 10.136/bmj.b2921.
(4)  Hellwig, K, et al. Hormonal contraceptives and multiple sclerosis susceptibility (S34.003). Neurology April 8, 2014;82 no.10 S34.003. Abstract can be found at:
(5)  Tanis BC, et al. Oral contraceptives and the risk of myocardial infarction. NEJM 2001;345:1787-93.
(6)  Gillum, LA. Ischemic stroke risk with oral contraceptives. JAMA July 5, 2000;284:72-78.
(7)  van Hylckama Vlieg A, et al. Venous thrombotic risk of oral contraceptives, effects of oestrogen dose and progestogen type: results of the MEGA case-control study. BMJ 2009;339 doi:10.136/bmj.b2921.
(8)  Lindegaard O, et al. Risk of venous thromboembolism from use of oral contraceptives containing different progestogens and oestrogens. Danish cohort study 2001-9. BMJ 2011;343:d6423.
(9)  Wang CC, et al. Risk of HIV infection in oral contraceptive pill users: a meta-analysis. JAIDS 1999;May 1 21(1):51-58.
(10)  Franceschi S, et al. Genital warts and cervical neoplasia: an epidemiological study. Br J Cancer 1983;48:621-28.
(11)  Kahlenborn C, et al. Oral contraceptive use as a risk factor for premenopausal breast cancer: A meta-analysis. 2006 Mayo Clinic Proc 2006;81(10):1290-1302.
(12)  IARC 2007 Monograph 91. Combined estrogen-progestogen contraceptives and combined estrogen-progestogen menopausal therapy. Available at:
(13)  Dolle J, et al. Risk factors for triple negative breast cancer in women under the age of 45. Cancer Epidemiol Biomarkers Prev 2009;18(4):1157-65.
(14)  Moreno V, et al. Effect of oral contraceptives on risk of cervical cancer in women with HPV infection. The IARC multicentric case control study. Lancet 2002;Mar 30;359(9312):1085-92.
(15)  Daniels, K, et al. Contraceptive methods women have ever used:  Unites States 1982-2010. US Dept of Health & Human Services, Centers for Disease Control & Prevention, National Health Statistics Reports. No. 62, Feb 14, 2013.
(16)  Ovulation method of natural family planning. Available at:
(17)  Dr. Zhang DW et al. The effectiveness of the ovulation method used by 688 couples in Shanghai. Reproduction and Contraception. June 1993;13,(3):194-200.

©2015  Breast Cancer Prevention Institute
All rights reserved.

Ordering information

Call toll-free: 1-86-NO CANCER (1-866-622-6237)

Breast Cancer Prevention Institute

Breast Cancer Prevention Institute
Breast Cancer Prevention Institute

All images and content are Copyright 2015 Breast Cancer Prevention Institute.
Small quantities of this brochure can be printed for personal use.

dropshadowtr.gif (161 bytes)
dropshadowbl.gif (166 bytes) dropshadowbr.gif (161 bytes)