What are the possible causes of weight gain on the pill?
Any fat gain is unlikely to be related to the pill, although there may be a few women who gain weight when they start taking it.
The oestrogen in contraceptive pills is known to have an effect on fat cells, but although it makes them larger, it doesn’t cause them to multiply.
One of the reasons you might appear to gain a little weight when you start taking the contraceptive pill is that you could retain more water at certain times of your cycle than you’re used to, but this shouldn’t be a significant amount of weight, and it’s not permanent. Weight gain on the pill can be particularly noticeable in your breasts, hips and thighs.
Like some of the other potential side effects of the contraceptive pill, this slight weight gain is a temporary inconvenience and should only last a few months.