Claude C Butler Explains:
Weight gain, from taking birth control pills, has been proved a myth by multiple studies in the last decade. If on a pill and you notice a slight weight gain it might be a temporary side effect (that will go off in 3-6 months) or you need to consult with your physician about changing it. Birth control pills are either progestin-only pills or combination pills, which contain estrogen and progestin. The chemical composition of estrogen is said to be constant across most pills and it is the progestin that varies across brands. So a change in pill might solve the issue. Make sure you give any pill at least three months for any side effects to pass.
Estrogen based pills stimulate renin-angiotensin compounds in the kidneys that can lead to fluid retention.
