I today went to see a gynecologist and i was told that i am 8 weeks and 4 days pregnant but my last period was 13 december... is it possible that i might have had my period while i was pregnant?. i havent had my period since then. thanks in advance.

Fetal dates ?'s: If your last bleeding episode was "13 December", it may not have been a menstrual period. There are occasions where a second twin may miscarry, with some bleeding. At this point, it is impossible to tell, but if your ultrasound shows a viable "8w 4d " pregnancy, your last "true" menstrual period would have been in November. Your OB physician may have other information, so check with him/her.

Pregnancy dating: We (OB MD's) use the last known menstrual period (LMP) as a standard way to "date" a pregnancy even thought the first two weeks of that time from ovulation has not occurred and conception was also not present. That is why the EDC (estimated date of confinement) is an estimate. Any spotting/bleeding since 12/13 was probably implantation bleeding. Fetal dating gets more accurate later.