Couple days of bleeding or am I pregnant?

Patient: Could I be pregnant? On February 6th, the day after my last period, my boyfriend’s ejaculate dripped onto my vagina. Just one drop and I washed up right away. Then a few weeks later, we were in his bed and I may have sat in some of his pre-ejaculate. We haven’t had sex. But could I be pregnant? On march 13th and 15th, I bled for about an hour each morning. It was really really light. My normal periods are very heavy and last 7 days. So I’m not sure if this was my period or what. I took 4 pregnancy tests, 3 before the days I bled, and 1 on the 21st of march. They all came back negative, however I did not use my first urine of the morning because the instructions said after you miss,it isn’t required to be the first one. My cycle used to range anywhere from 30-42 days between periods, but recently it has been more like 24-30 days between. I’m 18 and not sure why my periods are still irregular. Is there something wrong with me? Could I be pregnant? Was the couple days of bleeding my period? Help please. I’ve been having cramps the last couple days, but no bleeding yet. My breasts always get sore before my period and that hasn’t occurred and didn’t the last one either. What is going on?

Doctor: Thank you for your query.Even a drop of semen can make a woman pregnant if the count & motility of the semen sampl e are good. Even though it was washed off, we never know how effective & spontaneous this washing was. Regarding sitting on the pre-ejaculate we cannot comment because the contact of it with vagina has to be there for the sperms to swim up the genital tract. Pregnancy may not be on cards in your case as you say that the home pregnancy test done even on the 21st of March is negative. Just to be sure you can go for a blood test for pregnancy which will be more accurate in diagnosing pregnancy. The other best option would be to consult a doctor who will do a scan to know the underlying reasons causing for delay in the menstrual cycle.Hope that answers your query. Have a good day.