For women on the oral contraceptive pill, mood changes are common and can be a reason why they stop taking it. A new study has found a link between taking the combined oral contraceptive pill and the risk of depression, especially in younger women.
The combined oral contraceptive (OC) pill, which contains estrogen and progestogen, has been used in the United States since 1960. The hormones stop the ovaries from releasing an egg and also make it hard for sperm to reach an egg or for an egg to implant itself in the lining of the uterus. When taken correctly, the combined OC is more than 99% effective at preventing pregnancy. The combined OC pill can also be used to treat heavy menstrual bleeding, polycystic ovaries, endometriosis, and acne.
Mood changes are a side effect experienced by some women when they start taking OCs. It can influence their decision to start or continue taking the pill, particularly if they have a history of depression. But past research into the effect of OCs on depression risk has yielded inconsistent findings, possibly because women who discontinued OCs due to mood changes were omitted from these studies, producing what’s known as a 'healthy user' bias.
A new study by researchers at Sweden’s Uppsala University used a large sample to explore the risk of depression associated with starting the combined oral contraceptive pill and the effect of OC use on depression over time.
Using data collected from the UK Biobank, the researchers followed 264,557 women from birth to menopause. Data included their use of combined OCs, when they were first diagnosed with depression and when they first experienced symptoms of depression without receiving a diagnosis.
They compared women who’d been taking OCs to those that never had and analyzed the data to estimate the associated risk of depression for all women and for women separated into two age groups: adolescents (started OCs before age 20) and adults (started OCs at age 20 or older).
The researchers found that during the first two years of OC use, there was an increased rate of depression compared with women who’d never used OCs. In terms of age, the data showed that women who began using OCs as teenagers had a 130% higher incidence of depressive symptoms. Among adult women, the corresponding increase was 92%.
They say that the high percentage seen in adolescent women may be attributable to the hormonal changes of puberty.
“The powerful influence of contraceptive pills on teenagers can be ascribed to the hormonal changes caused by puberty,” said Therese Johansson, lead author of the study. “As women in that age group have already experienced substantial hormonal changes, they can be more receptive not only to hormonal changes but also to other life experiences.”
The researchers found that after two years, the increased incidence of depression declined in women who continued to take OCs. But, for adolescents, the incidence of depression remained high even after they stopped taking the pill, something that wasn’t observed in adult OC users.
They emphasized that, for most women, combined OCs are effective, and they don’t produce negative mood changes.
“It is important to emphasize that most women tolerate external hormones well, without experiencing negative effects on their mood, so combined contraceptive pills are an excellent option for many women,” Johansson said. “Contraceptive pills enable women to avoid unplanned pregnancies, and they can also prevent illnesses that affect women, including ovarian cancer and uterine cancer. However, certain women may have an increased risk of depression after starting to use contraceptive pills.”
The researchers say their findings should be used to ensure health professionals are aware of the possible link between OCs and depression and to inform women that depression is a potential side effect.
“Although contraception has many advantages for women, both medical practitioners and patients should be informed about the side effects identified in this and previous research,” Johansson said.
In the current study, the researchers only looked at combined OC pills. There are other methods of contraception that they intend to explore in future research.
“Since we only investigated combined contraceptive pills in this study, we cannot draw conclusions about other contraceptive options, such as mini pills, contraceptive patches, hormonal spirals, vaginal rings or contraceptive rods,” said Johansson. “In a future study, we plan to examine different formulations and methods of administration. Our ambition in comparing different contraceptive methods is to give women even more information to help them take well-informed decisions about their contraceptive options.”
The study was published in the journal Epidemiology and Psychiatric Sciences.
Source: Uppsala University
