A newer type of birth control pill that has gained popularity in recent years carries the same risk of breast cancer as a more traditional version, according to a study.
In the past, most women preferred a “combination” contraceptive pill containing two hormones, estrogen and progestin.
In recent decades, however, more and more people have opted for a progestogen-only pill – although prescriptions for the two different types are now the same.
Now a new study shows that the progestogen-only pill carries the same increased risk of breast cancer as its older equivalent.
In the past, most women preferred a “combination” contraceptive pill containing two hormones, estrogen and progestin. But now prescriptions for the progestogen-only pill are on par
Previous research has shown that women who use combined birth control pills or have recently stopped using them have about a 20 percent increased risk of developing breast cancer compared to women who do not take them.
A team from the University of Oxford analyzed data from more than 9,000 women who developed invasive breast cancer between the ages of 20 and 49 and 18,000 closely matched women who did not develop the disease.
The analysis found that those who were taking or had recently stopped taking the newer progestogen-only pill also had a 20 to 30 percent increased risk of breast cancer.
However, this effect seemed to wear off once the women stopped taking it, with no additional risk 10 years after stopping contraception.
Their findings were also applicable to both types of hormonal contraceptives taken in any form – be it an injection or an implant.
WHICH CONTRACEPTIVE METHODS ARE THERE CURRENTLY AVAILABLE?
Contraception aims to prevent pregnancy. A woman can become pregnant when a man’s sperm reaches one of her eggs.
Contraception tries to prevent this by keeping the egg and sperm separate, by stopping egg production, or by preventing the sperm and egg from attaching to the lining of the uterus.
Contraception is free for most people in the UK. Available options include:
- caps or diaphragms
- combined pill
- condoms
- contraceptive implant
- contraceptive shot
- contraceptive patch
- female condoms
- IUD (Intrauterine Device or IUD)
- IUS (intrauterine system or hormonal coil)
- Natural Family Planning (Fertility Awareness)
- progestin-only pill
- vaginal ring
The team said their research, published in the journal Plos Medicine, helps fill a gap in knowledge about the risks associated with taking hormonal contraceptives.
But they said those risks need to be weighed against the known benefits of taking it.
Gillian Reeves, Professor of Statistical Epidemiology and Director of the Department of Cancer Epidemiology at Oxford University, said: “I don’t really see that there is any indication here that women really need to change what they do.
“Yes, there is an increase here, and yes, nobody wants to hear that something they take increases their risk of breast cancer by 25%.
“The main purpose of this research was really to fill a gap in our knowledge.
“We have known for many years that combined oral contraceptives that women have been using for decades also have an effect on breast cancer risk, a small increase in risk that is transient.
“We weren’t quite sure how effective these progestin-only contraceptives would be.
“What we have shown is that they are exactly the same in terms of breast cancer risk, they seem to have a very similar effect to the other contraceptives and the effect that we have known for many years.”
Kirstin Pirie, statistics programmer at Oxford Population Health and one of the lead authors, said: “The results suggest that current or recent use of all types of progestogen-only contraceptives is associated with a similar small increase in breast cancer risk associated with.” the use of combined oral contraceptives.
“Given that a person’s underlying risk of developing breast cancer increases with age, the absolute excess risk of breast cancer associated with either type of oral contraceptive is lower in women who use it at a younger age .
“However, these excessive risks must be seen in the context of the known benefits of using contraceptives during the woman’s reproductive years.”
dr Commenting on the study, Kotryna Temcinaite, Head of Research Communications at Breast Cancer Now, said: “These research suggest that there is a small increased risk of developing breast cancer in women while using a newer progestogen-only drug or while stopping shortly thereafter contraceptives.
“The risk is about the same as with the older combined estrogen-progestin pill that we have known for some time. With both types of birth control, this extra risk of breast cancer decreases over time when you stop using it.
A team from the University of Oxford analyzed data from more than 9,000 women who developed invasive breast cancer between the ages of 20 and 49 and 18,000 closely matched women who did not develop the disease. The analysis found that those who were taking or had recently stopped taking the newer progestogen-only pill also had a 20 to 30 percent increased risk of breast cancer
“The study did not look at what hormonal contraceptives the women might have used in the past, or how long they had been on progestogen-only birth control.
“It also didn’t take into account whether a family history of the disease contributed to her risk. Therefore, more work is needed to help us fully understand the effects of using this type of birth control.
“Breast cancer is rare in young women. A slight increase in risk during the time a woman is using hormonal contraceptives means only a small number of additional cases of the disease will be diagnosed.”
Professor Stephen Duffy, from the Center for Prevention, Detection and Diagnosis at Queen Mary University of London, added that the results are “reassuring in that the effect is small”.
NHS figures in 2008 showed that there were just under six million prescriptions for the combined hormonal contraceptive in England, compared with less than two million for the progestin-only pill.
However, by 2020 the gap had closed and prescriptions for both totaled around 3.2 million.