Oct 29, 2008
Found this on-line and thought it interesting.
What Are My Chances Being Pregnant With a Negative Pregnancy Test? Am I Pregnant?
A repeatedly negative pregnancy test when you missed your period means that you are not pregnant and after a week of a missed period with negative pregnancy tests your chance being pregnant is 1%.
The timing of a positive pregnancy test depends on implantation. If you are pregnant then a urine pregnancy test is not expected to be positive until at the very earliest 3-4 days after implantation, which is about 10 dpo days after ovulation/fertilization (4 days before the next period), and about 51% of pregnant women have a positive pregnancy test 2 days before the expected next period. What are your chances of still being pregnant when you are trying to conceive and have a negative pregnancy test? What are your chances getting a positive HPT if you are pregnant? Below is a table showing your chances of still being pregnant with a negative pregnancy test on different days of your menstrual cycle:
Pregnancy Chances after a Negative Pregnancy Test in Relationship to Ovulation and the Days before or after the Expected Period
(DPO) AF due Chance of Still Being Pregnant %Not Pregnant %of women who test positive
12 DPO EP -3 12.3% 87.8% 51%
13 DPO EP -2 9.5% 90.5% 62%
14 DPO EP -1 8.0% 92.0% 68%
15 DPO AF 6.5% 93.5% 74%
16 DPO EP +1 5.3% 94.8% 79%
17 DPO EP +2 3.8% 96.3% 85%
18 DPO EP +3 2.5% 97.5% 90%
23 DPO EP +7 1% 99.0% 96%
Date are based on the fact that in each menstrual cycle there is an about 25% chance of getting pregnant as well as a scientific study published by Wilcox in JAMA in 2001.
Your chance of getting pregnant each month may be different depending on your age, certain medical issues, whether you ovulate or not, and if your are trying to get pregnant with IVF or other fertility medications.
Besides being pregnant, the next reason for missing your period is not ovulating (anovulation). That's why it's essential for every woman who TTC to chart her fertility and to know precisely each cycle if ovulation happened or not. Knowing if and when you ovulated usually removes any confusion you may have if your period didn't come. Start charting your fertility NOW. It helps you find out if you ovulated, whether you are fertile, and it will let you know early on if you are pregnant. If you know you ovulated and your period hasn't come 15+ DPO, then there could be only one reason: You are pregnant. If you know that you did not ovulate then you can often expect your period not to come and you are prepared for that.