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Notes on Women's Health
Notes on Women's Health

Can You Get Pregnant While on the Pill? Here’s How it Can Happen

Can You Get Pregnant While on the Pill?Oral contraceptive pills (also known as “the pill”) are a widely popular and effective form of birth control. Millions of women in the U.S. rely on birth control pills to prevent pregnancy. In fact, the Centers for Disease Control states that oral contraception pills are the second most common form of birth control for women in the U.S. age 15-49. The most common reason for taking birth control pills is to prevent pregnancy; however, women can also take birth control pills for other purposes, such as reducing menstrual cramps, regulating menstruation and reducing migraines. 

Contraceptive pills are considered a highly effective form of birth control when taken properly. However, unintended pregnancies can happen when the right guidelines are not followed. These unintended pregnancies are typically preventable. Here is what you need to know about getting pregnant on the pill so you can avoid any surprises.

How Do Birth Control Pills Work?

Combination birth control pills, containing both estrogen and progesterone, work primarily by preventing your body from ovulating. Ovulating occurs when a woman’s ovaries release an egg during menstruation each month.  The estrogen and progestin hormones found in birth control prevent the ovulation cycle. Progestins also help protect women from unintended pregnancy by thinning the endometrium (where an egg is implanted after fertilization), making it less suitable for implantation, thickening of the cervical mucus, making it impenetrable to sperm and impairment of fallopian tube mobility.   

There are also progesterone-only birth control pills. In contrast to combination birth control pills, some progestin only-pills do not consistently suppress ovulation, making the changes on cervical mucus, fallopian tube mobility and the endometrium the critical factors that prevent conception. 

It’s important to note that birth control pills do not protect women against sexually transmitted infections (STIs).   

How Effective Are Birth Control Pills?

When used correctly, combination birth control and progestin-only birth control is 99% effective for preventing pregnancy. However, there are a few factors that can reduce its effectiveness. In reality, approximately 9 out of 100 women taking birth control become pregnant each year.

How You Can Become Pregnant While on the Pill

As stated, when taken perfectly, birth control pills have high success rates for preventing pregnancy. However, there are a few instances that can decrease its effectiveness. Here are some of the factors that can cause birth control to fail:

  • Missing a day: Birth control works best when taken on a regular schedule – every day at the same time. Missing a day or forgetting to take it can cause the hormones that work to prevent pregnancy to become inconsistent. If you do not think you can commit to taking a pill at the same time each day, another form of birth control may be better suited for you. Learn about the different forms of birth control that are offered at Dr. Garofalo’s practice.
  • Not starting a new pack right away: Try to stay ahead of your prescription so you can start your new pack the day after the old one ends. Even missing a single day between packs may increase your chances of becoming pregnant. And don’t forget to take the pills at the end of the pack, either. Though they don’t do anything chemically, they are really important as a way to keep on schedule.
  • Vomiting: If you’re taking the pill while you’re sick, it’s possible you may vomit it out before it has absorbed into your system. If you vomit shortly after taking a birth control pill, it is recommended to take another pill to ensure it is absorbed.
  • Medications: Some medications may interfere with birth control, including antibiotics like rifampicin and anti-fungal drugs like griseofulvin. You should use backup contraception while on these medications and for 48 hours after finishing them.

What Do I Do If I Miss a Day?

The CDC recommends that for a single missed pill, take the missed pill as soon as possible. Backup contraception is not always necessary in this case but is a good idea anyway in the interest of absolute safety. If you have missed more than one pill, only take the most recently missed pill, discarding the rest. In this case, you should use backup contraception until you have taken your pills every day for a full week.

If you are worried your birth control has failed and you had unprotected sex, you may need to take emergency contraception (the morning after pill). Depending on the type of pill, this can prevent the start of a new pregnancy for up to 3-5 days after unprotected sex. However, it is not a good idea to consistently rely on emergency contraception, since these pills are much more powerful than regular birth control and may cause side effects.

If you think you may be pregnant or have any additional concerns, please reach out to your OB-GYN. A qualified doctor can help address your concerns and figure out the best course of action for your needs.

About the Connecticut OBGYN Practice

Dr. John Garofalo, M.D., is a CT OBGYN based in Fairfield County, providing care for Norwalk, Darien, New Canaan, Weston, Rowayton and the surrounding areas. He has more than 20 years of practice and surgical experience covering many facets of obstetrics and gynecology.

Laury Berkwitt, APRN, is a nurse practitioner specializing in women’s health in Fairfield County, Connecticut. Women undergoing signs and symptoms of menopause can make an appointment with Laury for Hormone Replacement Therapy. Laury has a passion for providing quality women’s health care in a safe and comfortable manner by creating a trusting patient-practitioner relationship. She has been in practice for more than 10 years, caring for women of all ages.