When is the Best time to take a Pregnancy Test?
You need to wait until the embryo has implanted into the uterine lining so that HCG (human chorionic gonadotropin) can leach from the embryo to the maternal serum. This usually happens about 9-11 days after ovulation or 4 to 6 days before you miss your period, provided that you have regular cycles. Women who ovulate irregularly will need to take an ovulation test to see when they ovulate and then count forward 9-11 days before trying to take a sensitive urine pregnancy test. Even then, the HCG levels may be too low to detect pregnancy until you get closer to missing your period or actually miss it altogether.
For low HCG environments, such as the day right after implantation, a blood test might be best because it is very sensitive and will give you a read out of what the actual level of HCG was in the serum. HCG levels vary a great deal from pregnancy to pregnancy so the absolute value of the HCG level isn’t as important as measuring the test again in 48 hours, after which a normal pregnancy will have doubled the serum HCG level. If you see this doubling, you know you are probably dealing with a healthy pregnancy and not an ectopic pregnancy or miscarriage.