News Highlights
Obesity increases risk of blood clots for women taking birth control pill
Obesity and taking combined contraceptives—including the birth control pill, patch and ring—are two of the many factors known to increase a woman’s risk of blood clots. But for women that fit both these criteria the risk appears greater, according to new research.
Synthetic forms of the hormones estrogen and progestin, the main ingredients in combined contraceptives, increase the risk of venous thromboembolic disease (VTE), the formation and travel of blood clots in the body. These clots include deep vein thrombosis, which form in the legs or pelvis, and pulmonary embolism, clots that block the arteries from the heart to the lungs.
Obese women are thought to have an increased risk of clots. This may be due the factors tied to obesity that promote clotting, such as slow blood flow and increased body mass index—a measure of obesity relative to weight and height.
This study done in the Netherlands examined patients diagnosed with blood clots between 1999 and 2004. Over 3,800 patients were compared to over 4,600 controls. The odds of getting a blood clot increased by a factor of 3 in obese women not taking oral contraception. In obese women taking oral contraception, the odds of getting a blood clot increased by a factor of nearly 24 times.
The results of this study add evidence to the theory that there is a causal relationship between obesity and the risk of blood clots. Genetic disorders that already increase the risk of VTE are more dangerous when obesity enters the equation.
Although the risk of blood clots is low in most women of reproductive age who use combined contraceptives, the elevated risk that comes with obesity should be considered when choosing a contraception method.
Pomp ER, le Cessie S, Rosendal FR and Dogger CJM. Risk of venous thrombosis: obesity and its joint effect with oral contraceptive use and prothrombotic mutations. British Journal of Haematology. 2008;139:289-96.
FOR HEALTH PROFESSIONALS
Breast cancer risk small for oral contraceptive users
Oral contraception (OC) is a much smaller risk factor for developing breast cancer than previously thought, according to the latest research.
For the last 40 years, debate has focused on the impact that the estrogen and progesterone hormones contained in birth control pills have on the development of breast cancer. Now researchers are saying that the risk is likely very small for a number of reasons.
Today’s pills contain much less estrogen than in the past, and the forms of estrogen that are used have less severe side effects associated with their use, namely acne and mood changes. In fact, the benefits of the pill outweigh the risks for most young women. Hormonal contraception also provides benefits that have nothing to do with sex. Decrease in bone loss and benign breast disease are both tied to the pill. Same goes for protection against endometrial and ovarian cancers.
There are many risk factors for breast cancer, and the greatest of these is age. An older woman’s risk of breast cancer is ten times that of a younger woman. The risk doubles when a mother, sibling, or daughter has breast cancer.
Oral contraceptive use is one of the weakest known risk factors for breast cancer, increasing the risk by 1.24 times. This figure is based on data pooled from a number of studies that together involved over 50,000 women with breast cancer and 100,000 without. The small risk was no longer present 10 or more years after discontinuation.
Another large study conducted in 2002 found that OCs did not increase a woman’s risk of breast cancer. This finding was based on examining 4,500 cases of breast cancer and 4,500 controls. This calls into question the results of studies held in the past, when pills contained higher doses of progestin and estrogen in different combinations.
Women can be reassured that the oral contraceptive pill plays a very small role in breast cancer risk. The risks associated with the newer formulations of the hormones are still unknown, but likely to be very small. Future studies will provide more precise estimates of the risks for new pills on the market today.
Casey PM, Cerham JR and Pruthi S. Oral contraceptive use and the risk of breast cancer. Mayo Clin Proc. 2008;83(1):86-91.
Should women in the older reproductive age group use hormonal contraception?
Women 40 years of age and older have many things to consider when choosing hormonal contraceptives. They are less likely to get pregnant, but if that happens there is a higher risk of complications like diabetes and hypertension.
The risk of blood clots is higher in women using contraceptives containing estrogen, a risk that is heightened by age and obesity. Women 40 and up using combined contraceptives still have a low risk of blood clots—a one in a thousand chance—but it is four times that of an adolescent. Women who have genetic disorders that predispose them to clots should choose methods that do not contain estrogen. Combined contraception elevates their risk of having clots.
Smoking and high blood pressure multiply the risk of stroke or heart attack for women taking combined contraception. Women who are over 35 and smoke or have high blood pressure should consider other options. So should older diabetic women who already have an increased risk of these medical complications. Women in this age group who are healthy, however, have not been shown to have an increased risk of stroke or heart attack, even if they are over 30 when they start it.
The effect of combined contraceptives on risk of stroke in women with migraines is controversial. Some studies have shown increased risk only in women who have migraine with aura, whereas others have not separated the two in their analyses.
Recent studies of large samples found no increase in the risk of breast cancer with oral contraceptive use, and that also stands for women who started using combined contraceptives at the age of thirty and older (see the article in this edition reviewing breast cancer risk with combined contraceptives). There is also evidence that even women who have a family history of breast cancer are posed no more a risk than anyone else.
There are also many benefits associated with hormonal contraceptive use that may help with needs of perimenopausal women. Irregular and heavy bleeding may improve with oral contraceptive use, injectable progestins, and the levonorgestrel-containing intrauterine device. Vasomotor symptoms may also be relieved by both combined and progestin-only forms of contraception. As women age, bone density decreases and users of estrogen-containing contraceptives show increases in bone mineral density.
Oral contraceptives also decrease the risk of ovarian cancer by more than 50%, and that protection lasts for up to 30 years. Endometrial cancer risk is also decreased by 50% or more with a greater duration of use, persisting for at least 20 years. The risk of colorectal cancer may also be decreased.
The author of this review recommends combined contraceptives for healthy, non obese women in this age group who do not smoke, who have no hypertension, diabetes or migraines. Women with any of these conditions should instead consider progestin-only or intrauterine forms of contraception. Women who are obese but have no other medical conditions can generally use combined contraceptives, but the risks and benefits must be evaluated on an individual basis. Nonhormonal options to consider include sterilization and barrier methods.
Kaunitz AM. Hormonal contraception in women of older reproductive age. N Engl J Med 2008;358:1262-70.
New Content on sexualityandu: Genital Piercing
Just as some people get their ears pierced, others choose to pierce their genitals and nipples with jewelry. Whether you are thinking about getting your first piercing down there, or you are a veteran in the piercing parlours, there are procedures you can follow to minimize the health risks.
Learn more about genital piercing.
Ask Sexualityandu
Sometimes my birth control patch starts to peel off at the edges and I’m not sure if it is still working. What should I do when this happens?
The patch may be reapplied if it has not been stuck to another surface, there are no debris on the adhesive, and it has not been reapplied. If it is partly or completely lifted off the skin and these criteria are met, you may attempt to stick it on again.
If this does not work, or these criteria are not met, then it depends on how long the patch has been partly off. If it has been less than 24 hours, put on a new patch and continue as usual and you will be protected. Change this patch on your usual patch change day even though it will be less than a week from when it was applied. If the patch has been only partially applied for an unknown amount of time or for longer than 24 hours, then start a new four week cycle with a new patch and a new patch change day, and use a backup method of contraception for one week.
Does Depo-Povera® decrease your sex drive when used for long periods of time?
Decreased sex drive, although uncommon, has been reported in 1-5% of women using Depo-Provera®. It is not necessarily related to how long you use it. There are many causes for decreased sex drive. Talk to your doctor about this and about potentially trying another method of birth control to see if your libido gets a boost.
I am currently using Depo-Provera®. I have heard that a lot of people have problems getting pregnant after they stop using it – is this true?
Depo-Provera® is an injectable progestin given as a shot in the muscle, although it may also be given in the fatty tissue just under the skin (subcutaneously) in a slightly different dose. It does not alter a woman’s ability to become pregnant, but it certainly delays the return to fertility. The medication is absorbed gradually so that one shot lasts for three months at a time. This lag time in clearing the medication from the system also means that its effects may linger and may prevent ovulation for up to one year, but on average for 9 months. After this delay, pregnancy rates are similar to women who haven’t used Depo-Provera®.
I am currently using the Nuvaring® and would like to start trying to get pregnant soon. Will using the Nuvaring® affect my ability to get pregnant?
A Nuvaring® user should release an egg within 2-4 weeks of taking it out, on the condition that periods were regular before starting the ring. If before you started using the Nuvaring® your cycles were irregular and you were having difficulty becoming pregnant, the problem may reappear when the Nuvaring® is stopped. If that’s the case, you may need to consult a gynaecologist.
I have been on the pill for about 18 years. I was always told it was safe and it will not prevent me from having a baby when I am ready. I am now 37 and got off the pill five months ago. I have not had my period since and I’m not going through menopause. The doctor gave me medicine to have a period to make sure my ovaries are working and they are. I have not had a period since and I really want to get pregnant. Did being on the pill that long interfere with my chances? I don't want to take fertility drugs if I can prevent it—what do you suggest?
The pill does not decrease fertility and women should return to normal cycles within three months of stopping the pill. A history of irregular cycles prior to starting the pill is an indication of reduced fertility that often goes undetected until later in life when a woman stops the pill and tries to become pregnant.
Fertility declines with age and decreases significantly at 37 years of age. You may need fertility drugs to stimulate your ovaries. Have your family doctor refer you to a gynaecologist to ensure there are no other issues and to help you become pregnant if necessary. Make sure your referral from the family doctor mentions your age and the difficulties you’ve had with irregular cycles so your appointment is prioritized.
For more information, see Top Ten Myths About the Pill.
