1. Oral daily pills (21 days of pills + 1 pill free week)
2. Monthly injectables (once a month)
3. Vaginal rings ( inserted for 3 weeks + 1 ring free week)
4. Skin patches ( 1 patch per week for 3 weeks + 1 patch free week)

They contain a mixture of synthetic estrogen and progesterone hormones in different concentrations. Now how do they work? Simple, they prevent ovulation from happening all together and as a backup plan, they make implantation harder in the uterus, so yeah its quite an effective contraceptive.

It also has some nice bonus benefits such as reduction of heavy menstrual flow and some women actually use the daily pills for this benefit. It also has been said to reduce the risk of cervical and ovarian cancers and its use is generally independent of intercourse.

On the flip side, it may cause some weight gain and for the oral pills which is the most readily available, affordable and used, it may be hard to keep up with the daily schedule thus leading to missed pills. While on the subject of missed pills, here is what to do if that happens : if one or two days maximum were missed, simply continue taking the pills the moment you remember and you are good. However, if it is more than two days missed, still take the tablet immediately and continue however u will need to use barrier protection for the next seven days.

Lastly, if u miss a pill within the last week of the pill Callender, you continue once you remember but however, you will commence the next sachet immediately and skip the pill free period for that month in addition to using barrier protection for the next seven days.

Warning: people who have preexisting conditions that can predispose them to thromboembolic crisis (formation of clots within the vessels) should avoid combined hormonal contraceptives. Conditions like prolonged bed stay, recent stroke, any form of vascular disease including hypertension, and also females above 35 years who smoke are not advised to use this either. Also as a pre operative precaution, hormonal contraceptives should also be stopped.
Other forms of combined hormonal contraceptives have essentially the same side effect profile and a few more advantages because they have higher levels of compliance which means chances of forgetting to take them are significantly reduced.