When it comes to “perfect” sex, timing is everything!


My doctor put me on an antibiotic for a sore throat, and the pharmacist warned me that it is going to interfere with my birth control pills.  Two of my sorority sisters said they use “pulling out” whenever they need extra protection.  Does this really work?  And should I worry about the antibiotic making my pills less effective?

These are two great questions!  Let’s knock out the easy one first – do antibiotics interfere with birth control pills?

We covered this question in detail a few months ago, but the short answer is that as long as you’re taking your pills at the same time every day (give or take 2 hours) then back-up contraception shouldn’t be necessary.  If you’re having problems taking your pills consistently because of your illness – your sore throat is so severe that you can’t swallow them, or you’re vomiting and having diarrhea to the point that your body can’t absorb them, then you should use some back-up protection just in case. 

Now, on to the question of whether withdrawing the penis from the vagina before ejaculation (“pulling out,” “the withdrawal method,” “coitus interruptus”) will prevent pregnancy. 

Whenever we talk about the effectiveness of any form of birth control, we look at two very important statistics: annual pregnancy rates during typical use and during perfect use.

Perfect use is where everything works according to plan and instructions: you never miss a pill; you use a condom every time and nothing slips off or breaks; your boyfriend pulls out in time, every time. 

But as we all know, life ain’t perfect.  So we also look at the typical use rates of pregnancy – how effective the method is in the real world, where condoms slip and pills get skipped and guys forget to retreat.

For women counting on the withdrawal method alone, 4% will become pregnant each year with perfect use while 27% will become pregnant each year with typical use.  To give you a comparison, 2% of women using condoms alone will become pregnant with perfect use while 15% will become pregnant with typical use. 

As you can see, the withdrawal method isn’t very good.  It puts tremendous pressure on the male partner.  He has to be able to reliably tell when he’s going to ejaculate and have the control to pull out.  This is difficult under the best conditions; throw in extenuating circumstances like alcohol or drug consumption and it gets even harder (no pun intended).  

The big question you have to ask yourself is, “What would a pregnancy mean to my life”?  If it is not an option, then make sure to take your pills consistently, keep a box of condoms close by and forget about withdrawal.  Or better yet – tell your boyfriend to get you some hot soup and himself a cold shower.  You need to take it easy until you feel better!

Beth Askue, MS, CNP
Student Health Services
The Ohio State University