Q:

I began birth control in June and I just started having sex with my partner. We have chosen not to use condoms at this time because we have discussed our sexual histories with each other and are one another's first partners. I am just wondering about the risks, specifically for pregnancy, if we do not use condoms. I understand that there is risk for STI's, but what are the risks for two individuals who have not had ANY other sexual contact with anyone else? Would it make that much of a difference to use a condom? I just want to know how much of a difference it would make if we used condoms.

A:

As health care providers, we assume that there is always a small risk of transmission of an STI, simply because of the odds that at least one member of a couple has had some intimate contact with another person. Even honest partners can have a memory that is clouded by alcohol, unwanted sex, and/or be too embarrassed to admit a brief sexual encounter.

Having said that, it sounds like you and your partner have been candid, are mutually respectful of one another's risk, and have not had any previous partners. Thus your risk of STI/STD transmission is extremely low. Short of interviewing you both, however, we cannot quantify your risk.

The risk of pregnancy for an average couple, using birth control pills perfectly, is less than 1:100 per year (based on an average frequency of intercourse 2x/week, or no more than 10x/ month). In reality, few women take their pills perfectly (same time every day, never a missed pill), so the true risk of pregnancy lies somewhere between 1:100 and 8:100. To keep your risk as low as possible, you should know what to do if/when you miss pills, which always calls for a back-up method such as condoms, for the week following any missed pills.