Evaluation of the Contraceptive Efficacy

Combined oral contraceptives are not the preparation of first choice in breastfeeding women as they may influence the quality and quantity of breast milk. In these cases, a progestogen-only pill is a suitable alternative, since progestogen-only pills contain no estrogen at all and a much lower dose of progestogen than do combined oral contraceptives

Therefore, progestogen-only pills may also be more acceptable than combined oral contraceptives to women suffering from medical conditions that are associated with the use of combined oral contraceptives (e.g. nausea, headache and breast tension).

The most widely prescribed form of hormonal contraception is the combined oral contraceptive, which offers good contraceptive efficacy and a number of non-contraceptive benefits.

However, the combined pill has also been associated with some adverse effects, mainly related to the vascular system, i.e. a slightly higher risk of venous thromboembolic events .

Most studies have linked the risk of venous thromboembolic events dose dependently to the estrogen component. Estrogen-containing oral contraceptives may, therefore, be contraindicated in women with risk factors for venous thromboembolic events.

The current progestogen-only pills contain levonorgestrel, norethisterone, lynestrenol or ethynodiol diacetate have a multifaceted, mode of action .

Ovulation inhibition is achieved in about half of the cycles and contributes only partly to the effectiveness of the method, with effects on the cervical mucus and the endometrium, thus providing additional contraceptive reliability .

Drawbacks of the traditional progestogen-only pills in comparison to COCs are the high incidence of irregular bleeding, the higher rate of ectopic pregnancies and a slightly lower contraceptive efficacy. If a newly developed progestogen-only pill improves on one or more of these drawbacks, it may be a valuable addition to the traditional progestogen-only pills .

Levonorgestrel, also known as the morning-after pill, is a first-line oral emergency contraceptive pill with approval from the World Health Organization to prevent pregnancy. It is FDA-approved to be used within 72 hours of unprotected sexual intercourse or when a presumed contraceptive failure has occurred .

Desogestrel is a selective progestogen with a lower androgenic activity than the progestogens used in the traditional progestogen-only pills. Therefore, a dose that is high enough to obtain inhibition of ovulation is not likely to trigger androgen-related side-effects. Levonorgestrel is a second-generation synthetic progestogen that is the active component of the racemic mixture of norgestrel. It binds to progesterone and androgen receptors, where it can delay gonadotropin-releasing hormone from being released from the hypothalamus .

Drospirenone is a synthetic spironolactone analogue and progestin with progestational and anti-mineralocorticoid activity. Drospirenone binds to the progesterone receptor; the resulting complex becomes activated and binds to specific sites on DNA. This results in a suppression of LH activity and an inhibition of ovulation as well as an alteration in the cervical mucus and endometrium. This leads to an increased difficulty of sperm entry into the uterus and implantation. This drug is used in oral contraceptives.

Eligibility Criteria:
Inclusion Criteria:

* Age: 18 - 45 years.
* Non obese women with BMI between 18.5 : 29.9 kg/m2.
* Healthy women with good physical and mental health.
* Sexually active.
* Women have normal cycles (regular interval, duration, and amount of bleeding.
* Women willing to accurately fill in the diary card with daily information on vaginal bleeding and pill intake
* Women willing to give written informed consent.

Exclusion Criteria:

* obese medical history
* Contraindications to the use of progesterone only pills with medical eligibility criteria mec category 3 or 4: (malabsorptive procedures, current or history of ischemic heart disease, history of cerebrovascular accident, systemic lupus erythematosus, breast cancer, cirrhosis, liver tumors or antimicrobial therapy).
* Women with allergy from study medications.
* Women refusing to participate in the study.