An increased risk of the following serious adverse reactions has been associated with the use of oral contraceptives (see WARNINGS section):

• Thrombophlebitis
• Arterial thromboembolism
• Pulmonary embolism
• Myocardial infarction
• Cerebral hemorrhage
• Cerebral thrombosis
• Hypertension
• Gallbladder disease
• Hepatic adenomas or benign liver tumors

There is evidence of an association between the following conditions and the use of oral contraceptives, although additional confirmatory studies are needed:

• Mesenteric thrombosis
• Retinal thrombosis

The following adverse reactions have been reported in patients receiving oral contraceptives and are believed to be drug related:

• Nausea
• Vomiting
• Gastrointestinal symptoms (such as abdominal cramps and bloating)
• Breakthrough bleeding
• Spotting
• Change in menstrual flow
• Amenorrhea
• Temporary infertility after discontinuation of treatment
• Edema
• Melasma which may persist
• Breast changes: tenderness, enlargement, and secretion
• Change in weight (increase or decrease)
• Change in cervical ectropion and secretion
• Possible diminution in lactation when given immediately postpartum
• Cholestatic jaundice
• Migraine
• Rash (allergic)
• Mental depression
• Reduced tolerance to carbohydrates
• Vaginal candidiasis
• Change in corneal curvature (steepening)
• Intolerance to contact lenses

The following adverse reactions have been reported in users of oral contraceptives, and the association has been neither confirmed nor refuted:

• Premenstrual syndrome
• Cataracts
• Changes in appetite
• Cystitis-like syndrome
• Headache
• Nervousness
• Dizziness
• Hirsutism
• Loss of scalp hair
• Erythema multiforme
• Erythema nodosum
• Hemorrhagic eruption
• Vaginitis
• Porphyria
• Impaired renal function
• Hemolytic uremic syndrome
• Budd-Chiari syndrome
• Acne
• Changes in libido
• Colitis

Read the Ovcon (norethindrone and ethinyl estradiol tablets) Side Effects Center for a complete guide to possible side effects »

Reduced efficacy and increased incidence of breakthrough bleeding and menstrual irregularities have been associated with concomitant use of rifampin. A similar association, though less marked, has been suggested with barbiturates, phenylbutazone, phenytoin sodium, and possibly with griseofulvin, ampicillin, and tetracyclines.

Interactions With Laboratory Tests

Certain endocrine and liver function tests and blood components may be affected by oral contraceptives:

1. Increased prothrombin and factors VII, VIII, IX, and X; decreased antithrombin 3; increased norepinephrine-induced platelet aggregability.
2. Increased thyroid-binding globulin (TBG) leading to increased circulating total thyroid hormone, as measured by protein-bound iodine (PBI), T₄ by column or by radioimmunoassay. Free T₃ resin uptake is decreased, reflecting the elevated TBG, free T₄ concentration is unaltered.
3. Other binding proteins may be elevated in serum.
4. Sex-binding globulins are increased and result in elevated levels of total circulating sex steroids and corticoids; however, free or biologically active levels remain unchanged.
5. Triglycerides may be increased.
6. Glucose tolerance may be decreased.
7. Serum folate levels may be depressed by oral contraceptive therapy. This may be of clinical significance if a woman becomes pregnant shortly after discontinuing oral contraceptives.

Last reviewed on RxList: 8/7/2008
This monograph has been modified to include the generic and brand name in many instances.