Question: 

If I cum inside a girl while she's on the birth control pill, can she get pregnant?

Answer by family medicine physician Heather Eberspacher, MD:

The pill is a tiny oral medication a woman can take at the same time each day to prevent pregnancy. Also called an oral contraceptive, the pill can help make periods more regular and less heavy. Some birth control pills can also help clear up acne. 

If your partner uses the pill perfectly, it's 99% effective. But nobody's perfect, so the actual effectiveness is closer to 93% effective. That means about 7 people out of 100 pill users get pregnant each year. 

Ways to increase birth control pill effectiveness:

• Take the pill at around the same time every day
• If you accidentally miss a day, take your missed pill as soon as you can. Then take the next pill at your normal time
• Know which drugs limit the pill's effectiveness

I always emphasize that you are never locked into one birth control option. If one method doesn't work for you, you can try something else. 

If you want to combine two different birth control options – like the pill and a condom – you'll have a much lower risk of unplanned pregnancy. Condoms have the added benefit of protecting you against sexually transmitted infections like HIV, gonorrhea and chlamydia.

Do condoms work? 

When used correctly and consistently, condoms are another form of birth control. There are two types of condoms:

1. External (male) condoms are worn over the penis during sex. External condoms are 98% effective when used correctly and consistently. Before you put on your condom, make sure to get any air out of the tip.
2. Internal (female) condoms are used in the vagina or anus during sex. Internal condoms are 95% effective when used correctly and consistently. Be sure the internal condom doesn't get twisted. The thin, outer ring should remain outside the vagina or anus during intercourse.

Ways to increase condom effectiveness:

• Choose the right size of condom. Too small of a condom can lead to tears, which will allow semen to escape. Too large of an external condom may slide off the penis
• Latex condoms provide the best protection against HIV. If you or your partner has a latex allergy, plastic or synthetic rubber condoms are good alternatives
• Use water-based or silicone-based lubricants with condoms. Oil-based lubricants can cause condoms to tear, which can cause pregnancy
• Don't use an external (male) condom with an internal (female) condom because it can cause tearing
• Use a condom just once, then dispose of it in the trash. Reusing condoms can cause unplanned pregnancy
• Don't use condoms that are expired, torn or damaged