Experiencing a positive pregnancy test after a suspected miscarriage can be unsettling and confusing. While it contradicts the expectation of a negative result, a positive test is possible. This article explains why this happens and outlines important steps to consider.
Understanding Pregnancy Tests and Miscarriage
Home pregnancy tests detect human chorionic gonadotropin (hCG) in urine. This hormone begins to be produced by cells that form the placenta shortly after a fertilized egg implants in the uterus. As a pregnancy progresses, hCG levels typically rise rapidly, often doubling every 36 to 48 hours in the initial weeks.
A miscarriage is the spontaneous loss of a pregnancy before 20 weeks of gestation. Most miscarriages occur during the first trimester. Common signs may include vaginal bleeding and abdominal pain.
Reasons for a Persistent Positive Test
A pregnancy test might remain positive after a miscarriage due to the continued presence of human chorionic gonadotropin (hCG) in the body. Even after a pregnancy loss, hCG levels do not immediately drop to zero. Instead, they decline gradually as the body processes these hormonal changes.
Pregnancy tests are designed to detect even very low levels of hCG. Therefore, if any detectable amount of the hormone is still circulating, the test can register as positive. This indicates the presence of the hormone, not necessarily an ongoing viable pregnancy. The body needs time to eliminate the hCG that accumulated during the pregnancy.
Factors Influencing Test Outcomes
Several factors influence how long human chorionic gonadotropin (hCG) remains detectable after a miscarriage. The gestational age at which the miscarriage occurred plays a role; if the pregnancy was further along, initial hCG levels would have been higher, requiring more time to decline. For example, hCG levels can return to normal within a few days for a very early loss, but may take up to a month or more for a miscarriage that occurs later in pregnancy.
The completeness of the miscarriage also affects the decline. If some pregnancy tissue remains (known as an incomplete miscarriage), it can continue to produce hCG, leading to a slower decrease in hormone levels. In a complete miscarriage, hCG levels typically decrease by approximately 50% every 48 hours. Individual physiological variations mean the exact timeline for hCG to return to a non-pregnant level (typically below 5 mIU/mL) can vary from a week to around six weeks.
When to Seek Medical Guidance
If a pregnancy test remains positive after a suspected miscarriage, or if concerning symptoms arise, seek medical guidance. Heavy bleeding, such as soaking through more than two pads an hour for several hours, warrants immediate medical attention. Other symptoms like severe abdominal pain, fever, chills, or foul-smelling vaginal discharge also require prompt medical evaluation.
Medical follow-up is necessary to confirm miscarriage completeness and to monitor hCG levels. Healthcare providers may perform blood tests to track hCG decline and may use ultrasound to check for any remaining tissue. A persistent positive test several weeks after a miscarriage could indicate retained products of conception or, in rare instances, other conditions that require treatment.