Birth Control Pills. Day? for how long?

Dear Ma'am,   Thank you for your query regarding birth control pills. The active medication in combined birth control pills is an estrogen (ethinyl estradiol) usually in the dose of 20- 30 ug and a progestrogen (norethistrone, Levonorgestrel,  desogestrol) in the same or varying amounts. (eg. Ovral, ) Newer pills contain drospirinone with the estrogen.  ( Yasmin, Yaz) There are some pills which only contain progesterone ( Cerazette) which are used in women in whom estrogen can't be given or is breast feeding. Pills may be Mondphasic, biphasic or triphasic depending upon the relative amounts of Active drug in the pill. May be taken monthly (21- active pill and 7 placebos, or 24 active pills depending upon the brand you buy). Some pills are designed to be taken for 3 months continously so that 4 menses occur in a year. They can be taken at any fixed time of the day to be started from D1 of the menstrual cycle, preferably at night to minimize side effects. More importantly it is essential to note that no pill is missed.  Before commencing the pill: A gynaecological consult is needed to rule out - Active pregnancy. - Thrombophila. - Severe liver disease. - Malignant breast lump. - Hypertensive Heart disease. - Other drug use interfering with efficacy of COC - Screening for sexually transmitted diseases. A young women may continue a combined oral pill till - Desire for pregnancy. - Beyond 40 years with comorbidities. - Long acting method of contraception is required. - New onset comorbidities,  especially a thrombosis event or a breast or gynaecological cancer. The failure rate for COC's is less than 1 in 100 women years of ideal use. Do let me know if there are any further queries. Regards, Aditi