Women who used oral contraceptives as teenagers are at a greater risk of depression as adults, according to a new Canadian study, but experts say don’t jump off the pill wagon yet.
The researchers surveyed more than 1,200 women and grouped them into three categories – those who used hormonal birth control pills as teenagers, those who used as adults only, and those who never used them at all.
They found that women who used the pill as teens were between 1.7 and three times more likely to develop clinical depression than women who never used the pill.
The risk was consistent even years after first use – when women had stopped taking the pill.
Lead researcher Christine Anderl, a postdoctoral fellow at the University of British Columbia’s psychology department, said the relationship between the pill and depression also went unchanged when other factors – like smoking history and age of first sexual intercourse – were controlled.
However, she stressed that these findings do not prove that one causes the other.
“It’s impossible to say anything about causality just based on this data,” she told Global News. “None of these variables explain the link, but that doesn’t mean that we might not have unintentionally missed the real thing.”
Anderl said studies on animals have shown changes to sex hormones during puberty can have an “irreversible” impact, but studies on humans are “less clear.”
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While there appears to be a wave of women choosing to get off the pills, Anderl said that the findings shouldn’t deter people from the method.
She hopes the study fosters more discussion about the pros and cons of contraceptives of all kinds.
“I think it’s a very personal choice for each woman,” she said. “Some options might just be better for one young woman than the other.”
Dr. Dustin Costescu, a family planning specialist and assistant professor in the Department of Obstetrics and Gynecology at McMaster University, agrees.
He suggested the study be taken with a grain of salt.
“Nobody is questioning the importance of birth control,” he told Global News.
“I think this study adds validation that if you’re having mood effects related to hormonal contraception use, there may be a better or different option out there for you.”
This isn’t the first time researchers have looked at a possible link between the two.
In 2016, a Danish study surveyed more than one million women and found a link between women currently on the pill and an increased risk for depression. The same study, considered to be the largest on the topic to date, showed the link was particularly strong in teens.
Costescu said the problem with studies on this topic is how common both the pill and depression are in people independently.
“Birth control is one of the most commonly prescribed medications globally. Depression is well known to be what’s called multifactorial in nature,” he said.
“It’s hard to study things that everyone’s using against an illness that’s very common and caused by multiple factors.”
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Oral contraceptives come in a variety of hormonal strengths and are not always prescribed strictly to prevent pregnancies. The women surveyed in the UBC study were not asked about the type of pill they were using, so that was not factored into this study. The data also did not show whether the risk of depression increased for women who took the pill for a longer period of time, past adolescence.
Anderl said their research is just “one piece of a much larger picture” and that further study is needed on the long-term effects.
The team has launched a follow-up study which will look at hormone levels of women aged 13 to 15 over several years. Along with looking at a link to depression, the new study will delve into the type of pill or hormone level and the reasons why the teens are taking them.
As the UBC researchers point out, oral contraceptives are particularly popular among teens. In the U.S., more than half of sexually active women aged 15 to 19 use the pill. In Canada, oral contraceptive use has dropped, according to a survey by the Society of Obstetricians and Gynaecologists of Canada, as more women rely on other forms.
Though the age of first sexual intercourse hasn’t changed, women are choosing to prevent pregnancies longer than in the past, Costescu said.
This means young women are on birth control pills for longer.
“We need to meet their goals and expectations,” he said, “which is a decade of not getting pregnant.”
The doctor’s advice for those experiencing mood changes on the pill – talk to a doctor first.
“With this study, it doesn’t mean stop the medication right now. It means have a conversation first.”
“I can tell you there is a method of risk control out there for everybody,” Costescue said. “The key is to have the conversation, listen to what the goals are, and find the right one.”