Today, most home pregnancy tests boast of being about 99% reliable. responsible for verifying the presence of thehCG hormone – human chorionic gonadotropinthe hormone produced by the placenta when a woman is pregnant – home pregnancy tests can detect pregnancy through urine 12 to 14 days after conception. The hCG level usually doubles every 72 hours for 8 to 11 weeks of pregnancy, then remains constant and then drops after delivery.
If present at the time of the urine test, the pregnancy hormone will cause a chemical reaction that will indicate whether a pregnancy exists or not. Often a pregnancy is signified by the appearance of two lines, and a negative result will be shown by a single line.
While these home tests are in most cases reliable, it may be thata false positive appears at the time of the result. A deeply traumatic experience, both for women who deeply want to get pregnant, but also for those who absolutely do not want to be. Here are the reasons that could explain this strange result.
You let the test sit too long
If you do a test at home, it is important to scrupulously respect the instructions specified in the instructions for use and in particular the waiting times. If you don’t wait long enough, the result is obviously not going to be reliable. But conversely, if you let it sit too long, theurine on the test can evaporate and give the impression of two lines instead of one.
The pregnancy test is expired
Another common reason women receive a false positive result is because of pregnancy test expiration date. If its date has passed, the chemical responsible for detecting hCG will no longer be able to do so correctly, and thus, the risk of error is higher.
You are undergoing fertility treatment
If you are undergoing treatment for your fertility, it is possible that the medicine you take or the injections that are part of in-vitro fertilization (IVF) contain hCG. If you test too soon after taking medication or after an injection, you may get a false positive.
It can happen to women”who are very motivated and trying to conceive, and they will often take the pregnancy test early and see a positive result, which is obviously very exciting for them at firstsays Zev Williams associate professor of obstetrics and gynecology to the magazine Glamour. But it could just be the result of the fertility drugs they took. This is something we warn patients about, so they don’t get false hopes when they see the positive test..”
You still have hCG in your blood after childbirth or miscarriage
According to one study of Lancet published in April 2021, miscarriages affect one in 10 women in their lifetimewith an estimated 23 million miscarriages worldwide.
After childbirth or a miscarriage, hCG can persist in the body for several months. According to one other study published in The Journal of Clinical Endocrinology and Metabolism, it takes four to six weeks for levels to return to normal. Indeed, part of the placenta may still be present and therefore release hCG for a certain period.
You had an ectopic pregnancy
An ectopic pregnancy occurs when the pregnancy takes place outside the uterus, i.e.a fertilized egg develops outside the uterusoften in the fallopian tubes, cervix or ovaries.
The embryo will then produce hCG which will indicate a positive result, but the pregnancy is not viable : an embryo cannot develop in an area other than the uterus. An ectopic pregnancy can even be dangerous for the health of the mother.
Its main symptoms are intense pain in the abdomen and pelvis during pregnancy, abnormal vaginal bleeding, dizziness or shoulder pain. In case you experience any of these symptoms, do not hesitate to contact your doctor.
Sources:
- Miscarriage matters: the epidemiological, physical, psychological, and economic costs of early pregnancy loss, The LancetApril 2021
- Hypothesis: persistently elevated hCG causes gestational ovarian overstimulation associated with prolonged postpartum hyperandrogenism in mothers of aromatase-deficient babies, The Journal of Clinical Endocrinology and Metabolism, August 2013
Read also:
- “Having a miscarriage”: why we must (finally) put an end to this formulation
- Why are obese women advised to lose weight to get pregnant (when it is not helpful)?
- Miscarriage: it would be linked to changes in the vaginal microbiome
