The Side Effects of Microval

Microval, also called Levonorgestrol, is manufactured by Wyeth Pharmaceuticals. It is a contraceptive drug designed to prevent pregnancy in women who chose to take it as an oral contraceptive. The contraceptive is particularly beneficial for women who are not able to take the hormone estrogen because it only contains the hormone progesterone. Microval is not marketed in the United States but is available in Australia, Chile, Venezuela and South Africa.


Microval is a progesterone-only contraceptive. (Progesterone is a female hormone secreted by the ovaries.) Its action as a contraceptive is to alter the cervical mucus, affect the endometrium (the cells that line the uterus) and disrupt the implantation of the egg into the uterus. Microval will even prevent ovulation in some patients. Microval should be taken as prescribed to get the maximum effects.

Side Effects

Microval may cause side effects. Its minor side effects may include enlargement, tenderness and secretion. There may also be nausea and or vomiting as well as a change in libido. It may also affect menstrual flow or cause slight inter-menstrual bleeding (usually temporary) along with on-and-off feelings of depression.

Potential Side Effects

These side effects include migraine, bloating and abdominal cramps along with an allergic rash, dysmenorrhoea (painful menstrual periods) and cervical changes that includes erosion and secretions. In addition there may be vaginal candidasis (yeast infection), drowsiness and puritis (an itch) along with intolerance to contact lenses. Report these symptoms to your physician for advice.

Additional Side Effects

Other side effects may include hair loss, changes in appetite and nervousness and dizziness along with vaginitis and cataracts. A serious side effect is the increased risk of thromboembolic and thrombotic disease, which is the development of a blood clot in a blood vessel leading to thrombophlebitis (a blood clot in the leg) or cerebral hemorrhage (bleeding blood vessel in the brain). This medication must be immediately discontinued if these conditions occur.


The use of an oral contraceptive like Microval is contraindicated (which means that it may increase risks) in women who have known or suspected pregnancy, undiagnosed abnormal genital bleeding or known or suspected carcinoma of the breast or genital organs. Other contraindications include cerebral-vascular or coronary artery disease as well as liver disease.


Pap smears or Papanicolaou smears (a test to detect precancerous cells in the cervix) should be done before taking Microval and periodical tests should be administered while taking it. Patients who are at risks for getting diabetes mellitus should have a blood-glucose reading done before taking Microval and periodical blood-glucose tests done during the administration. To avoid the risk of serious cardiovascular problems women taking contraceptives like Microval should not smoke.