Irregular Periods After Yasmin: Understanding Pregnancy Tests & Cycle Changes

Question
I am 20 years old. I have a 4-year old son will be 5 this November. My last menstrual cycle was on 7-20-04. I went to the doctor on 8-23-04 they took blood to see if I was pregnant. The test came back negative. My cycles are regular except this month. How accurate are the blood pregnancy tests. Also last year I had a problem with irregular cycles which my doctor finally recommended a medicine called Yasmin. I was on the pills for 4 months and this year ever since my cycles have always been regular. I also found out last year that I had small cysts on my ovaries and that my ovaries were swollen. I'm not sure if they still are because my doctor hasn't did any examines on me since the beginning of last year.IF they are still swollen could that be why I haven't gotten pregnant. I have a 4- year old son if I've already had a child should there be a problem with me having another.

Thank You for your help.

Answer
Pregnancy tests (blood or urine) are accurate if done at the correct time (seven days after missing  your period). If the pregnancy test was negative at that time, you are not pregnant. A further way to confirm this is to take two blood pregnancy tests, 48 hours apart. If the result is less than 5, you are not pregnant. If the test shows that there is a drop in the values in 48 hours, it indicates a miscarriage. If there is a rise in 48 hours, it indicates a viable pregnancy. If there is a plateau in 48 hours (stays the same), it may indicate the possibility of an ectopic pregnancy.