If you’re trying to get pregnant, you might be wondering when the best time to take a pregnancy test is. Some manufacturers, doctors, and friends might advise against taking a test before you’ve missed your period. Find out why and how the probability of a positive pregnancy test changes based on the days after ovulation (DPO).
We use a pregnancy test that is 25 mIU/HCG sensitive as our baseline for calculations. This test will show positive results if the HCG hormone in a woman’s urine exceeds this level. It is important to note that the HCG hormone becomes present in the blood immediately after implantation of the embryo in the uterine wall. Later, it will show up in a woman’s urine.
Implantation occurs when a fertilized egg attaches to the lining of the uterus. If fertilization occurs on the 7th day after ovulation, the level of human chorionic gonadotropin (HCG) hormone will “jump” to 2 mIU. The following day, HCG levels double and amount to “whole” 4 mIU. At 9 days post-ovulation (DPO), the level of HCG again doubles and amounts to 8 mIU. Even though the woman is already pregnant, her hormone levels are too low for the test with 25 mIU sensitivity to detect it, resulting in a negative result. Only on the 11th day after ovulation, HCG levels for the first time cross the border in 25″.
If implantation happens on the 10th day after ovulation instead of the 7th, the first pregnancy test results may not be visible until 14 days after ovulation. We are defining delay and answering common questions, like “When can I take a pregnancy test after ovulation?” Manufacturers advise taking pregnancy tests after a delay of at least 14 days, which is the length of the second phase following ovulation. Therefore, it is recommended to take the test no earlier than the 15th day after ovulation.
