Hand holding birth control pill packet


Hi Sexpert;

I’ve been on birth control the past 2 weeks, being new to it, I’ve either missed a day or taken them hours late numerous times. I’ve had unprotected/no pull-out sex about 5 times this week, including today which was my original ovulation day (before I started BC), am I at risk for pregnancy?


Dear Forgetful;

Thank you so much for your question! With our busy lives, forgetting to take an oral contraceptive method of birth control (i.e., the pill) happens to lots of people. It is great that you are making efforts to reduce your risk of pregnancy by using contraception; however, not taking it consistently while engaging in unprotected penetrative sex can increase your risk of becoming pregnant.

Birth control pills like many other forms of contraception are not 100% effective at preventing pregnancy. If you use birth control pills perfectly, meaning that you take it every day at the same time, it is over 99% effective. In reality, the pill is 91% effective because people are not perfect and forget to take or miss pills. If you forget to take the pill more than two days, the chance of ovulation (when a mature egg is released from the ovary and has the potential for fertilization) increases, meaning your risk of getting pregnant also increases.

How soon birth control takes effect after starting it depends on what kind of birth control you take. Combination pills (containing estrogen and progestin) can take anywhere from five to seven days after the first dose to become effective depending on when you begin taking the pill. Progestin-only pills, also known as mini pills, are effective after two days of starting the pill. During this time, it is best to use a second form of contraception such as an internal or external condom to prevent pregnancy. Progestin-only pills are really most effective if you take them at the same time every day. If you take the progestin pill three or more hours late, it is recommended that you use a backup-method for the next two days. If you are taking a combo pill and miss a day, you can take two pills the next day to get back on schedule. If you miss two or more consecutive pills anywhere in a combo pill pack, a backup birth control method, such as condoms or a diaphragm, is recommended for seven days. If you are unsure of which kind of birth control you are taking, ask your primary care physician, gynecologist, or a provider at McCosh and they will be able to provide more information regarding the effectiveness of the birth control you use.

If you are concerned about being pregnant, it is best to take a pregnancy test which can be purchased at the University Store, CVS on Nassau Street, or at McCosh Health Center. If you have any questions regarding how to use a pregnancy test or which one to purchase, feel free to make an appointment with a provider at McCosh.

If you choose daily birth control as your preferred method of contraception, is it very important that you take the pill every day to ensure its effectiveness. Missing just one day increases your risk of becoming pregnant. Setting a daily alarm or opting for a text reminder service can be helpful. If you continue to miss pills, it may be advisable to speak to your healthcare provider to discuss other contraceptive options, such as an intrauterine device (IUD), birth control patch, implant, or shot – which are sort of “set it and forget it” methods. If you are ever in doubt in regards to the effectiveness of your birth control or if you want to explore other options of contraception, speak to your primary care provider, gynecologist, or a provider at McCosh Health Services. You can make an appointment online at www.princeton.edu/myuhs.

— The Sexpert

Information on birth control provided Planned Parenthood, WebMD, and Bedsider