Estrogen VS Non Estrogen?

What is the difference between a Estrogen and a non Estrogen based contraceptive? Can the one cause weight gain?

First of all, the only contraceptive that commonly causes weight gain is the progestogen Depo injection. Weight gain is a rare side effect from all the rest.

Most of the serious side effects are caused by the oestrogen. Generally speaking, the progestogen only (mini pill) is safer and produces less side effects (with the exception of the implant and depo). The POPs only have a 3-4 hour efficacy window, 12 for Cerazette. Oestrogen containg contraceptives have a 12 hour window.

With POPs, 70% of women find that their periods cease completely after 6 months (and return when you come off the Pill), with the oestrogen containing Pills you will still have a monthly bleed.

Estrogen is not necessary in preventing pregnancy. Some people are sensitive to estrogen, or have estrogen dependent cancers and can not take it. Although the estrogen makes the pill easer on the body and can mimic the natural cycle. This combination (with estrogen and progestogen) is called multiphasic, which is more like the natural cycle

The POP (progestogen only pill) or mini pill must be taken at the same time everyday, and is more touchy to deal with.

Furthermore there are non-hormonal methods, barrier methods, (condom, cap, diaphragm, sponge, etc) spermicide, IUD, permanent sterilization and behavioural methods.