Do You Ovulate on the Pill?

Oral Contraceptives and Their Effects on Ovulation

Birth control pills prevent pregnancy by blocking the ovulatory process and making the body less hospitable to sperm and implantation.

Most women are aware of “the pill,” and many have used it, but few know the intricacies of how it actually works. Birth control pills are useful not only for preventing unwanted pregnancies, but also for regulating menstrual cycles and even treating acne. Whatever your reason for taking the pill, it’s helpful to know how it works and what effect it has on your cycle.

Types of Birth Control Pills

While they are all designed to prevent pregnancy, not all birth control pills are created equally. Combination pills and progesterone-only pills are the most common types of birth control pills for regular use, and a prescription from a health care professional is required to obtain them. Another pill, often called the “morning-after pill,” is designed for emergency use only; most are available over the counter. Combination pills contain a mixture of synthetic versions of the hormones estrogen and progesterone. The progesterone pill, also known as the “mini-pill,” contains no estrogen and is typically recommended for women who are breastfeeding, because estrogen can affect levels of milk production.

How the Pill Works

All types of birth control pills are oral contraceptives designed to prevent pregnancy. The combination pill works by blocking ovulation. Using synthetic versions of estrogen and progesterone, the combination pill balances hormone levels so that estrogen never surges. Since a peak in estrogen is what signals the ovaries to release an egg during ovulation, the combination pill disrupts the signal and prevents ovulation.

The progesterone-only pill works by making the body less receptive to sperm and implantation. The increased progesterone thickens cervical mucus to make it more challenging for sperm to travel and makes the lining of the uterus too thin for implantation. While the progesterone-only pill sometimes disrupts the ovulatory process, its main function is to prevent the sperm and egg from meeting—and to make the environment less conducive to implantation if they do anyway.

The morning-after pill uses the same synthetic hormones as the other pills and works in a similar manner, but, unlike regular contraceptives that must be taken daily at the same time, the morning-after pill delivers its hormonal punch in one shot. The sooner you take the morning-after pill following unprotected sex, the more effective it will be at preventing pregnancy.

How the Pill Affects Your Cycle

Birth control pills essentially interrupt your normal menstrual cycle. Though many women still experience monthly bleeding while they’re on the pill, it’s not because from their period. Though a pill is taken daily, only 21 of them are active and contain hormones. The remaining seven days consist of either no pills or sugar pills without hormones. The abrupt termination of synthetic hormones after 21 days triggers a withdrawal bleeding that is similar to and often confused with a menstrual period.

Side Effects of the Pill

Since the hormones in the pill essentially trick your body into thinking you are pregnant, many of the pill’s common side effects include pregnancy symptoms like nausea, sensitive breasts, headaches, weight gain and mood swings. Irregular spotting is also a common side effect of the pill. Taking birth control pills can increase the risk of blood clots too. If you are over 35 and smoke or have a history of health problems, your doctor may recommend alternative methods of contraception instead.

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