News Highlights
The links between ovarian cancer risks and contraception
A new study has looked at the impact that tubal ligation, and long-term use of birth control pills and intrauterine devices (IUDs) have on a women’s risk of ovarian cancer. This study followed a group of over 107,000 nurses aged 30-55 years for a period of up to 28 years from 1976 to 2004.
For women who used the pill for 5 years or more, the longer she was on the pill, the more her risk of ovarian cancer was decreased. With 10 or more years of use, the risk of ovarian cancer decreases by 38%. After a woman stops taking the pill, this benefit lasts for up to 20 years. After 20 years, the protective effect was no longer present.
The results of this study are consistent with many others that have demonstrated a decrease in ovarian cancer risk associated with oral contraceptive use.
Women who have had their tubes tied to prevent pregnancy, called tubal ligation, also have a decreased risk of ovarian cancer. The effects of different types of tubal ligation techniques and the time since the procedure have not been explored.
Contrary to what has been seen in two other studies, this study suggests that women who used IUDs may have an increased risk of ovarian cancer. However, the types of IUDs used thirty years ago, during the ‘70s and’80s, may not reflect the IUDs currently on the market. The link between IUDs and ovarian cancer must be studied further.
Infertility, described in this study as more than two years of unsuccessful attempts to conceive, was also associated with an increase in the risk of ovarian cancer. Other smaller studies have shown either a small increase or no increase in risk.
Other types of contraception such as rhythm method, diaphragm, condoms, foam, and spousal vasectomy were not associated with ovarian cancer risk.
Tworoger SS, Farifield KM, Colditz GA, Rosner BA, and Hankinson SE. Association of oral contraceptive use, other contraceptive methods, and infertility with ovarian cancer risk. Am J Epidemiol 2007;166:894-901.
Oral contraceptives do not affect risk of death from breast cancer
The relationship between oral contraceptives and breast cancer is important given the large proportion of women who use oral contraceptives at some period during their lifetime. Two previous studies have shown no increase in the risk of breast cancer associated with oral contraceptive use, and another study showed a slight increase in the risk of diagnosis if the pill was used in the last ten years. One study suggested an increased survival from breast cancer associated with birth control pill use.
According to a new study, oral contraception use has no effect on the survival of women who have been diagnosed with breast cancer.
Women aged 20 to 54 years old who were diagnosed with breast cancer were questioned regarding their history of using oral contraception and matched to a cancer database where information about their survival was collected.
Oral contraceptive use did not affect women survival after they were diagnosed with breast cancer. Variables such as age at first use, duration of use, and time since last use also had no effect on survival from breast cancer. The investigators also examined different types of birth control pills and found no association between survival and type of pill used.
Wingo PA, Austin H, Marchbanks PA, Whiteman MK, Hsia J, Mandel MG, Peterson HB and Ory HW. Oral Contraceptives and the Risk of Death from Breast Cancer. Obstetrics and Gynecology 2007;11(4):793-800.
FOR HEALTH PROFESSIONALS
Contraceptive failure rates
Within a year of using a new contraceptive, 12.4% of women experienced contraceptive failure.
These findings were published in a U.S. study that looked at patterns of typical contraceptive use and failure, based on a survey from over 7,600 women aged 15-44 between 1995 and 2002.
The most effective methods of reversible contraception during the first 12 months of use were injectables (such as Depo-Provera®) and oral contraceptives. The failure rate for injectables was 7% and the failure rate for oral contraceptives (OCs) was 9%. Withdrawal and male condoms resulted in failure 18% and 17% of the time, respectively. Fertility awareness methods resulted in the highest failure at 25%.
This study also examined estimates of contraception failure related to age, poverty and union status. Women aged 30 and older were less likely to have a contraceptive failure than women less than 30 years old. Women of lower socioeconomic status and women in cohabiting union had the highest risk of failure.
Kost K, Singh S, Vaughan B, Trussell J and Bankole A. Estimates of contraceptive failure from the 2002 National Survey of Family Growth. Contraception 2008;77:10-21.
Ask Sexualityandu
I had a Mirena® inserted over 2 months ago. I am really happy with it and I haven’t had any major side effects aside from a little irritability and unpredictable periods. The problem is that since I’ve had the IUD, I have had almost no sexual appetite at all! I have never heard of this as a side effect. Is this common?
Although this is not a common side-effect, it has been reported in less than 1% of women who use the Mirena®. Some of the progestin from the device enters your system and can cause the ovary to produce less testosterone. This is likely to lessen after the device has been in place for several months and less progestin is absorbed into your body.
Sometimes when my boyfriend is giving me oral sex, he blows air into my vagina – is this safe?
Blowing air into the vagina, or vaginal insufflation, can cause serious problems in pregnant women, but it rarely harms those who are not. An air embolism occurs when the air gets into blood vessels through the lining of the uterus. This complication can be fatal, so a sexual partner should never blow into the vagina of a pregnant woman.
Vaginal insufflation can also cause problems when air under pressure travels from the vagina through the cervix, uterus and fallopian tubes into the abdominal cavity. Air irritates the abdominal cavity and can cause serious pain and a phenomenon called “free air”—but that is more commonly associated with a hole in the gastrointestinal tract, a problem that generally requires surgery for treatment. Free air from vaginal insufflation only requires observation rather than surgery, but there have been multiple cases of women receiving unnecessary surgeries because the history of their sexual activities was not known.
I will be away on a three week vacation when I am due for my Depo-Provera® shot. What should I do?
Normally Depo-Provera® is given every 12 weeks. But if you can get your injection before 14 weeks from your last shot, you should be protected from pregnancy. If it will be 14 weeks or more before you can get your shot, then you will not be protected right away. If you had intercourse in the last 10 days, you should have a pregnancy test before your next shot and then use a backup method of contraception for the first two weeks after your injection. However, you will need another pregnancy test in 2 weeks. If you did not have intercourse in the last 10 days, you don’t need to do another pregnancy test 2 weeks after the first one. Another option is to have your shot early since it can be given as frequently as every 10 weeks, and you can rest assured you’ll be protect from pregnancy without any gaps of fertility.
