The accuracy of a pregnancy test after in vitro fertilization (IVF) will depend on the type of hormonal supplements and medications given during the course of treatment. Many women will receive injections of human chorionic gonadotropin (Hcg) to help sustain any resulting pregnancy, and this could cause pregnancy test results to be inaccurate. This is because Hcg is the same hormone produced by a developing embryo and is the one detected by most pregnancy tests to give a positive result. Artificial injections of Hcg could lead to a false positive.
In women who receive Hcg during the course of treatment, a pregnancy test after IVF may not be accurate if they are not actually pregnant. A home pregnancy test could pick up on the artificial hormones and give a positive result even in women who are not pregnant. Women who are in fact pregnant, though, will receive an accurate result. As a general rule of thumb, it is a good idea to wait 24 hours after every 1,000 units of Hcg given during treatment. After this time, a pregnancy test should be accurate, although every woman should discuss testing protocol with her doctor.
Women who do not receive Hcg during treatments may yield the same accuracy levels as any other woman when taking a pregnancy test after IVF. Most home pregnancy tests are about 99% accurate when taken one day after a missed menstrual period. When taken earlier, it is possible to get a false negative result because Hcg may not be present in high enough quantities for a standard test to detect at that time. Each type and brand of test may have its own sensitivity rating, so women are encouraged to research the kind they will be using.
No pregnancy test should be read after ten minutes has passed. Although rare, false positives have been known to appear once the testing period has lapsed. Any lines appearing after ten minutes are called evaporation lines, and they are the result of moisture evaporating off the test strip where a positive result would have appeared.
Most of the time women will be advised to take a pregnancy test after IVF in a doctor’s office or fertility clinic to ensure the most accurate results. Improperly taken tests could affect the outcome. Under the controlled atmosphere of a clinic, results may be more accurate. Blood tests which test the exact level of Hcg in the a woman’s system are the most accurate and are right nearly 100% of the time.
If a pregnancy test after IVF is negative, but no menstrual period comes after several weeks, a second test may be given. False negatives are fairly common when using urine tests and are usually the result of testing too early. An ultrasound may also be performed to attempt to detect a potential pregnancy, or to determine what other factors may be preventing the onset of a period.
