QuestionMy last period was March 17, 2004. I was on antibiotics from February 18 - March 19, in relationship to strep throat and mono.
I take ortho tri cyclen. I am 18, and was visiting my boyfriend in college - and we had a lot of sex over the 7 - 12 of April. I hadn't missed any pills, but I had some diarrhea, and that in conjunction with the antibiotics earlier inspired me to take Plan B on the evening of the 12th. My health care provider had instructed me to take both pills at one time rather then 12 hours apart. I should have started my period on the 14 of April, but haven't. Should I be worried about pregnancy or concerned? Is it just that shot of hormones that is delaying my period? Thank You.
AnswerIt is doubtful that you became pregnant for several reasons. Most antibiotics will not lower the efficacy of the pill (some will) and as long as you did not miss any pills, you probably were well protected and did not ovulate. Secondly, if you have a normal 28-29 day cycle (from the first day of your period until the first day of your next period) ovulation occurs on cycle day #14 (if you were not on the pill). You can only become pregnant if you have unprotected sex on cycle day #13, 14, 15, or 16. If your last period started on March 17, you could only have conceived on March 29,30,31, and April 1. If you had sex between April 7-12 it would have been too late for an egg to have survived or to have ovulated. Plan B was used correctly and the pills can be taken at the same time or one in the morning and one at night. Plan B will not delay your period. I would wait seven days from your expected day of menses and then repeat the pregnancy test, if you do not get your period by April 21.
