Hi, and thanks for your medical question on eHealth forum!
Well, yes, thick white discharge can be due to pregnancy, and if you have missed the periods, take a pregnancy test. A thick white discharge can be normally seen at the time of ovulation. So if you are any where near your ovulation date, then this is a possibility (say 10-17 days after the start of your last period as you are in). Thus though pregnancy too causes a white discharge, chances are less that you are actually pregnant now (if you are near ovulation date)âhowever you can become in the next few days if there is fertilization of egg with the sperm and it gets implanted. It is too early to confirm pregnancy now.
Yeast infection to begin with only causes a white vaginal discharge without causing itching or pain during sex.
Consult your gynecologist since a confirmed diagnosis cannot be given on net. Hope this helps. Take care!