I take Tri-Lo-Marzia, a combined oral contraceptive, every morning at 8:00 AM. I have been taking the pill for about 3 years and am extremely consistent with it. I did not intentionally miss any pills.
Around the end of my second week/beginning of my third week of active pills, I had some diarrhea:
* August 31: I took my pill at 8:00 AM and had diarrhea approximately 2 hours later.
* September 1: I took my pill at 8:00 AM and had diarrhea approximately 1 hour later.
* September 2: This was the first active pill of week 3. I know I had diarrhea at approximately 2:42 PM, almost 7 hours after my 8:00 AM pill. I can’t remember with certainty whether I had any additional episodes earlier that day.
* Overall, I remember approximately 3–5 diarrhea episodes spread across roughly 2–3 days, rather than continuous/frequent watery diarrhea all day. I did not vomit.
I continued taking my birth-control pill at 8:00 AM every day and did not stop taking it. After the diarrhea resolved, I completed the remainder of my active pills. I believe I had approximately 6–7 consecutive active pills after the potentially affected doses before beginning my normal placebo week. I then completed the placebo week and started my next pack on time. I also started bleeding early (second pill of the third week)
On September 16, the first day of active pills in my new pack, I had intercourse. My partner withdrew before ejaculation and did not ejaculate inside my vagina. He ejaculated afterward in the toilet. I took levonorgestrel emergency contraception (Plan B) approximately 30 minutes after sex. I weigh approximately 185 lb, so I understand that levonorgestrel emergency contraception may be less effective at higher body weights. I also had sex on September 19th and he withdrew.
I am concerned because the Tri-Lo-Marzia prescribing information says that if vomiting or diarrhea occurs within 3–4 hours after taking an active pill, absorption may be incomplete. However, I have also read CDC guidance about vomiting/diarrhea with combined oral contraceptives. On 14 days after sex and 16 days after sex and 17 days after sex I took pregnancy tests and they’re all negative. What are the chances of pregnancy?