Low-dose estrogen birth control pills may be a good option for women looking for birth control that doesn't cause weight gain, since estrogen can sometimes lead to mild fluid retention that affects body weight. However, most birth control pills do not directly cause weight gain.
Some people may notice slight changes in their weight while using birth control, often due to temporary fluid retention, increased muscle mass, or natural weight changes that occur with age.
To determine which birth control option is best for you, it’s important to consult a gynecologist. If you experience significant or persistent weight gain, your healthcare provider can check for underlying health issues that might be contributing to it.
Injectable birth control containing medroxyprogesterone acetate (Depo Provera) may cause some weight gain, especially in women under 18 or those with a body mass index (BMI) over 30.