In the laboratory we can test for the presence of pregnancy by measuring the level of beta-HCG in either the urine or the blood. Both types of tests are reliable and highly accurate but home pregnancy testing can yield both false positives and false negatives if performed too early. Performing a pregnancy test within 7 days after the egg collection procedure can result in a false positive result because of residual HCG after the shot is given to trigger the final maturation of the eggs. In addition, the urine pregnancy test may be spuriously negative if performed less than 14 days after the embryo transfer. In our practice, we have had patients with a serum beta-HCG level of more than 200 mIU/mL who nevertheless had a negative urine pregnancy test.
We advise patients to obtain a blood pregnancy test 12 to 14 days after an IVF embryo transfer and to avoid home pregnancy testing. In-office blood pregnancy tests provide the most reliable and accurate result.
Our RE highly encouraged us to wait for the blood test, and my husband was extremely adamant that I not do a home pregnancy test. He did not want me to be given false hope by a positive home pregnancy test that turned out not to be a viable pregnancy. The 2-week wait was extremely difficult, but we kept ourselves busy by planning a 5-day trip in the middle of it. I am really glad I did not do a home pregnancy test with our first IVF because it probably would have been positive, despite the outcome of a chemical pregnancy. To have the hope of pregnancy erased the next day by a low beta would have been more than I could handle emotionally at the time. On our second IVF attempt, I waited until I got the positive beta from the RE, and then I took many home pregnancy tests so I could see that double line for myself.