Starting a new birth control method can be tricky. Aside from actually picking a method, you might also have to put up with some annoying side effects as your body adjusts to a new medication. Twitter: @Emily_Stikeman A new double-blind study out of Sweden took a closer look at how people feel after starting a new birth control method. They gave 340 women either birth control pills or a placebo for three months. Altayb / Getty Images All of the women took a pill — either birth control pills with ethinylestradiol (a form of estrogen) and levonorgestrel (a form of progestin) or a placebo — every day for 21 days, followed by a break for 7 days. They did this for three months. Not even the researchers knew which participants were assigned to which group, making this a double-blind, randomized, placebo-controlled study (which is a pretty big deal in the world of birth control research). All the women were between the ages of 18-35 and were screened for certain health conditions before being included in the study. None of the women were using hormonal birth control at the start of the study, though some of them had used it in the past. And they were instructed to use non-hormonal birth control throughout the study (like condoms), since they wouldn't know if they were getting the birth control or the placebo. Before and after the study, all the participants took questionnaires designed to measure well-being and depression. Instagram: @darlingdistraction / Via instagram.com On the post-study questionnaire, the women in the birth control group showed a relatively small but statistically significant reduction in general well-being when compared to the placebo group. They also scored lower on measures of self-control and vitality. However, there were no statistically significant effects when it came to depressed mood or depressive symptoms. You can find an example of the questionnaire here. So why did women taking the pill feel more meh than women taking the placebo? Tap to play or pause GIF Tap to play or pause GIF giphy.com The study's author, Dr. Angelica Lindén Hirschberg, professor at Karolinska University Hospital, told BuzzFeed Health via email: "We do not know the mechanism, but we think it could be a direct effect of the progestin component on the brain." That's not a bad theory, said Dr. Mary Jane Minkin, OB-GYN and professor at Yale School of Medicine. All different types of birth control pills contain the same type of estrogen, but it's the progestin that varies from brand to brand, she said. And some people may react differently to different progestins. It explains why your best friend might love the same pill that made you moody and nauseous. So it's possible that some of the women in this study reacted negatively to the progestin in this pill, which was levonorgestrel. "When I [have a patient] go on a birth control pill, I really try to tailor the birth control pill to the patient," said Minkin. It's also possible that the women in the birth control group were experiencing some of the common side effects that happen when you first start hormonal birth control. Tap to play or pause GIF Tap to play or pause GIF FOX / Via giphy.com "Many women will experience breast soreness, breast enlargement, perhaps some mood changes, perhaps some erratic bleeding or breakthrough bleeding, some people may notice a weight change in either direction." said Dr. Alyssa Dweck, OB-GYN and author of the upcoming book The Complete A To Z Guide To Your V. These are fairly common side effects that can vary depending on the person and the pill formulation, but they tend to subside after two-to-three months. That's why gynecologists typically tell their patients to give it a few months to really see how you do on new birth control method, says Dweck, though they can always stop or change earlier if the side effects are more serious. The study didn't ask specific questions related to symptoms, but it's probably not a stretch to assume that a few annoying side effects might make you feel less amped about life that month. But there are also some study limitations worth nothing here. Tap to play or pause GIF Tap to play or pause GIF LOGO / Via giphy.com Like the fact that "general well-being" is a fairly broad topic that is hard to isolate from other variables, said Dweck. And the fact that the study only included 340 women and one birth control formulation. The length of the study may also be a limitation, since it's not uncommon for women to experience some mild side effects when they first start taking hormonal contraception.Plus, it's entirely possible that some women could guess they were in the birth control group, whether it be from breakthrough bleeding or suddenly having way easier cramps. Finally, we don't know if this reduced well-being affected anyone's decision to continue taking this particular birth control. As we know, loads of people deal with various side effects when they feel the pros outweigh the cons. If you take anything away from this study, it should be that not all birth control pills are alike, and the same formulation won't work for everyone. Twitter: @kadyrabbit If you're experiencing any side effects when taking birth control, bring it up to your doctor! This can include changes to your mood, libido, skin, headaches, etc. The solution could be as simple as switching you to another pill with another type of progestin that might work better for you. In fact, even name brands and their generics can react differently in certain people, said Dweck. "The progestins are very different, and we've got lots of things to try," said Minkin.