What Are Combined Oral Contraceptives?

Pills that contain low doses of 2 hormones—a progestin and an estrogen—like the natural hormones progesterone and estrogen in a woman’s body.

Combined oral contraceptives (COCs) are also called “the pill,” low-dose combined pills, OCPs, and OCs.

Work primarily by preventing the release of eggs from the ovaries (ovulation).

How Effective?

Effectiveness depends on the user: risk of pregnancy is greatest when a woman starts a new pill pack 3 or more days late, or misses 3 or more pills near the beginning or end of a pill pack.

As commonly used, about 8 pregnancies per 100 women using COCs over the first year. This means that 92 of every 100 women using COCs will not become pregnant.

When no pill-taking mistakes are made, less than 1 pregnancy per 100 women using COCs over the first year (3 per 1,000 women).

• Return of fertility after COCs are stopped: no delay
• Protection against sexually transmitted infections (STIs): none

Side Effects, Health Benefits, and Health Risks

Some users report the following:

Changes in bleeding patterns including:
– Lighter bleeding and fewer days of bleeding
– Irregular bleeding
– Infrequent bleeding
– No monthly bleeding

Headaches
Dizziness
Nausea
Breast tenderness
Weight change
Mood changes
Acne (can improve or worsen, but usually improves)

Other possible physical changes:

Blood pressure increases a few points (mm Hg). When increase is due to COCs, blood pressure declines quickly after use of COCs stops.

• Are controlled by the woman
• Can be stopped at any time without a provider’s help
• Do not interfere with sex

Known health benefits

Known Health Benefits Known Health
Help protect against:
Risks of pregnancy
Cancer of the lining of the uterus
(endometrial cancer)
Cancer of the ovary
Symptomatic pelvic inflammatory
disease
May help protect against:
Ovarian cysts
Iron-deficiency anemia
Reduce:
Menstrual cramps
Menstrual bleeding problems
Ovulation pain
Excess hair on face or body
Symptoms of polycystic ovarian
syndrome (irregular bleeding,
acne, excess hair on face or body)
Symptoms of endometriosis
(pelvic pain, irregular bleeding)

Known health risks

Very rare:
Blood clot in deep veins of legs
or lungs (deep vein thrombosis
or pulmonary embolism)
Extremely rare:
Stroke
Heart attack

• Do not build up in a woman’s body. Women do not need a “rest” from taking COCs.
• Must be taken every day, whether or not a woman has sex that day.
• Do not make women infertile.
• Do not cause birth defects or multiple births.
• Do not change women’s sexual behavior.
• Do not collect in the stomach. Instead, the pill dissolves each day.
• Do not disrupt an existing pregnancy.