Combined oral birth control pill

Combined Oral Birth Control Pill

The combined oral birth control pill, commonly referred to as "the pill," is a type of oral contraceptive that contains two hormones: estrogen and progestin. These hormones work together to prevent pregnancy by inhibiting ovulation, thickening cervical mucus, and altering the uterine lining.

Mechanism of Action

The primary mechanism by which the combined oral contraceptive pill prevents pregnancy is by suppressing ovulation. The estrogen component inhibits the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland, preventing the development and release of an egg from the ovaries. The progestin component thickens the cervical mucus, making it difficult for sperm to enter the uterus, and alters the endometrial lining, reducing the likelihood of implantation.

Types of Combined Oral Contraceptives

Combined oral contraceptives are available in various formulations, differing in the type and dosage of estrogen and progestin. Common types include:

• Monophasic pills: Each active pill contains the same dose of estrogen and progestin.
• Biphasic pills: The hormone dosage changes once during the cycle.
• Triphasic pills: The hormone dosage changes twice during the cycle.

Benefits

In addition to preventing pregnancy, combined oral contraceptives offer several non-contraceptive benefits, such as:

• Regulation of menstrual cycles
• Reduction in menstrual cramps and pain
• Decreased risk of ovarian and endometrial cancers
• Improvement in acne

Risks and Side Effects

While generally safe for most women, combined oral contraceptives can have side effects and risks, including:

• Increased risk of venous thromboembolism
• Elevated blood pressure
• Nausea, headaches, and breast tenderness
• Mood changes

Women who smoke and are over the age of 35 are at a higher risk of cardiovascular complications and are generally advised to use alternative forms of contraception.

Contraindications

Certain conditions contraindicate the use of combined oral contraceptives, such as:

• History of thromboembolic disorders
• Uncontrolled hypertension
• Migraine with aura
• Breast cancer

Usage

The pill is typically taken once daily, at the same time each day, for 21 days followed by a 7-day break during which withdrawal bleeding occurs. Some formulations include 28 pills, with the last 7 being inactive placebo pills to maintain the habit of daily intake.

Also see

• Progestin-only pill
• Intrauterine device
• Contraceptive implant
• Emergency contraception

• Birth control
• Contraception
• Dictionary of birth control
• Reproductive health