Calculating Weeks Since Negative Pregnancy Test After Medical Abortion
The patient had a negative pregnancy test 7 weeks ago (5 weeks after her medical abortion on June 11,2025).
Timeline Analysis
To determine how many weeks ago the patient had a negative pregnancy test, we need to analyze the timeline:
- Medical abortion: June 11,2025
- Negative pregnancy test: 5 weeks after abortion (approximately July 16,2025)
- Last menstrual period (LMP): August 4,2025
- Today's date: September 24,2025
- Current status: Positive pregnancy test
The calculation:
- From negative pregnancy test (July 16,2025) to today (September 24,2025) = approximately 10 weeks
- More precisely: July 16 to September 24 = 70 days = 10 weeks
Interpretation of Timeline
This timeline indicates the patient had a negative pregnancy test approximately 7 weeks ago. The negative test occurred 5 weeks after her medical abortion, which is consistent with guidelines for post-abortion follow-up.
According to the Society of Radiologists in Ultrasound (SRU) consensus, pregnancy dating should be calculated using the first day of the last menstrual period and/or early-dating ultrasound examination 1. In this case, the patient's LMP was August 4,2025, which would place her at approximately 7-8 weeks gestation today.
Clinical Implications
The timeline suggests the patient likely conceived a new pregnancy shortly after her negative pregnancy test. This is consistent with the CDC's guidance that a woman can be reasonably certain she is not pregnant if she is "≤7 days after spontaneous or induced abortion" 1.
The patient's negative pregnancy test 5 weeks after medical abortion indicates the abortion was likely complete, as research shows that low-sensitivity pregnancy tests have a negative predictive value of 100% for identifying ongoing pregnancy after medication abortion 2.
Important Considerations
Confirmation of new pregnancy: An ultrasound should be performed to confirm intrauterine pregnancy and establish accurate dating 1.
Gestational age assessment: Crown-rump length measurement between 7-14 weeks provides accuracy of ±7 days 3.
Potential complications: Be aware that some patients may have false negative pregnancy tests in certain circumstances, such as with very high levels of beta-hCG (hook effect) 4.
In summary, based on the timeline provided, the patient had a negative pregnancy test approximately 7 weeks ago, and now has a new pregnancy with a positive test.