The pregnancy test
The most sensitive, accurate and reliable pregnancy test is a blood test for the presence of b-HCG (human chorionic gonadotrophin).The HCG is produced by the embryo, and is the embryo's signal to the mother that pregnancy has occurred.
B-HCG can be measured in the blood and positive B-HCG (more than 10 mIU/ml) in the blood can be detected as early as 2 days before the period is missed.
Most clinics start testing B-HCG 14 days after egg collection.As the embryo grows rapidly, B-HCG normally double every 2 to 3 days.
Thus, one reliable sign of a healthy pregnancy is the fact that the B-HCG are increasing rapidly, and often doctors will ask for a repeat test.
A rising B-HCG is reassuring.
Typically, in a healthy singleton pregnancy, the B-HCG level is about 100 mIU/ml about 16 days after ovulation, though this level can vary considerably. The level are higher in multiple pregnancies; and lower in non-viable pregnancies and ectopic pregnancies.
Levels Vary from lab to lab but discuss all results with your doctor.
If the levels don't double as expected, this suggests that the pregnancy is unhealthy. Possibilities include a non-viable intrauterine pregnancy which will miscarry; or an ectopic pregnancy. Differentiating between the two conditions is obviously important, and this is where vaginal ultrasound plays a key role.
The major advantage of blood tests is the fact that they measure the actual level of the HCG in the blood - and this factor can be very helpful in managing pregnancy problems. many women after their fertility treatment sneak a test at home using a kit bought from the pharmacy.
Modern urine pregnancy kits are now quite sensitive and can detect a pregnancy as early as 1 to 2 days after missing a period (at a blood HCG level of about 50 to 100 mIU/ml).
The benefit of urine pregnancy test kits is that they are less expensive; and testing can be done at home by the patient herself.
However, instructions need to be followed carefully, and errors in interpreting the test results are not uncommon. These errors could occur if the urine is too dilute; or if the test is not done properly; or if there is a urinary tract infection exists.
