When women begin taking hormonal birth control they sometimes complain of side effects such as mood swings and weight gain. Now a large study conducted in Denmark has confirmed a link between taking birth control and depression.

When women take birth control, they introduce a mix of estrogen and progesterone into their system either through a pill, a patch worn on the skin, a ring, a shot or an intrauterine device. The researchers found that using hormonal birth control, especially in young women, was associated with being diagnosed with depression for the first time and with the use of antidepressants.

The researchers followed 1 million women ages 15 to 34 over a period of 14 years. About two women in 100 were diagnosed with depression first after being prescribed birth control, compared with one person in 100 who were not on birth control.

To eliminate the possibility that women weren’t correctly remembering when they were prescribed birth control, diagnosed with depression or prescribed antidepressants, the researchers drew that information from bar codes on prescriptions given to the study participants.

By coincidence, these results were released just before a different study reported on a possible birth-control shot for men. That study found it was 96 percent effective at preventing pregnancy, but the researchers stopped the trial. Why? While 75 percent of men said they were willing to use the birth control, a quarter of the men felt ill effects.

Research is continuing but it seems birth control, despite the side effects, will remain more of an issue for women than men.