Many years ago I remember seeing a young woman who had just been diagnosed with a stroke and the reason was because she was on a birth control pill.
She had a history of the arterial thromboembolic disease but she did not know this was a contraindication to using birth control pills. Sadly she died.
Oral Contraceptive Pills or birth control pills as they are sometimes called are a good way of preventing pregnancy, especially in women less than 35 and who are not smokers.
However, they are not for everyone. Women who have an active or history of breast cancer, stroke, heart attack, deep venous thrombosis or pulmonary embolism should stay clear off OCPs.
Other contraindications include ladies who have an undiagnosed abnormal 
vaginal bleeding, uncontrolled high blood pressure, or a history of a migraine with aura.
Sorry, but there is more. Women with jaundice with prior use of BCPs, pregnant women, smokers ( more than 15 sticks/day and older than 35 years) should not be on the pill.
The next set of conditions are relative contraindications so while they are not an absolute, avoid OCPs if you have a family history of breast cancer, embolisms, diabetes, hypertension, history of or current depression or bone mineral density changes.
In the same vein, you should know that OCPs may cause fluid retention so if you have a condition like a migraine, epilepsy or asthma (these conditions are exacerbated by fluid retention) you may want to reconsider BCPs as your first choice.
Finally, even if you don’t have any of the absolute or relative contraindications
you should stop using BCPs if you develop any of the followings while taking the pills: visual problems, jaundice, worsening depression, unusually severe migraine, or a big rise in your BP. If you are going for a major surgery, stop the pills 4 weeks before or if you are going to be immobilized for a long time please stop the pills.
By and large, the pills remain a very good choice for those who are good candidates and is encouraged if needed.
