Had sex yesterday. no contraception. afraid of pregnancy. brown discharge today, does that mean she's pregnant?

Always possible: Whenever you have sexual intercourse there is a risk of becoming pregnant (even on birth control-though the risk is much lower). Your discharge is a non-specific finding. The best way to find out is to check a urine pregnancy test. Depending on the test, you can usually start checking a few days before your expected next period.

Plan B: Anyone having sex without birth control or condoms is at risk of getting pregnant. Use over the counter Plan B if intercourse was within 72 hours to decrease the risk of unplanned pregnancy. Use condoms next time to avoid these scares. She should see an Obgyn to discuss her birth control options

Brown D/c: just means that old blood is being cleaned from the uterus and is not a pregnancy indicator. However - if she misses her period - it would be very important to take a pregnancy test. Use protection if pregnancy is not desired.