Human Chorionic Gonadotropin (HCG) is a hormone produced by the body early in pregnancy. It originates from cells that will eventually form the placenta. Its primary function involves supporting the corpus luteum, a temporary structure in the ovary that produces progesterone, essential for maintaining the early stages of pregnancy.
HCG’s Role in a Healthy Pregnancy
In a healthy and developing pregnancy, HCG levels typically follow a predictable pattern of increase. After implantation, HCG becomes detectable in blood and urine, usually around 8 to 11 days post-conception. These levels rise rapidly, often doubling every 48 to 72 hours during the first trimester. This rapid increase is generally considered a positive indicator of a viable pregnancy.
The consistent rise of HCG supports the uterine lining and prevents menstruation, nurturing the early embryo. This pattern continues until HCG levels peak around 8 to 11 weeks of gestation. Following this peak, levels naturally plateau and then slowly decline for the remainder of the pregnancy.
Defining a Missed Miscarriage
A missed miscarriage, sometimes known as a silent miscarriage, occurs when a non-viable pregnancy remains within the uterus. The embryo or fetus may have stopped developing or died, but typical miscarriage symptoms like vaginal bleeding or cramping are absent. This lack of outward signs means individuals may be unaware a pregnancy loss has occurred.
Missed miscarriages are often detected during a routine prenatal appointment when a fetal heartbeat is not found or the embryo appears smaller than expected. Because the body has not recognized the loss, it may continue to display early pregnancy symptoms, which can be particularly confusing. This absence of spontaneous expulsion distinguishes it from other types of miscarriage.
HCG Behavior During a Missed Miscarriage
When a missed miscarriage occurs, HCG levels typically do not continue to rise as they would in a healthy, progressing pregnancy. Instead, the HCG pattern can vary. Levels may plateau, showing little to no increase over several days, or they might begin a slow decline. In some instances, HCG levels can even remain stable before eventually dropping significantly.
The continued presence of HCG, even if not rising appropriately, can explain why a pregnancy test might still show a positive result. It also accounts for the persistence of early pregnancy symptoms like nausea, breast tenderness, or fatigue. Placental cells may not immediately cease their function after the embryo or fetus is no longer viable. This delayed recognition means HCG production can continue without the characteristic doubling pattern.
The rate at which HCG levels decline after a missed miscarriage is highly variable. Some may experience a quick drop, while for others, the decline can be very gradual over several weeks. This slow decrease can prolong the physical and emotional experience of the loss. The lack of a rapid drop means a missed miscarriage might go undetected for an extended period, as hormonal signals do not immediately reflect the change in viability.
Diagnosis and Management Following a Missed Miscarriage
Diagnosing a missed miscarriage typically involves a combination of medical assessments. A transvaginal ultrasound is a primary diagnostic tool that can reveal the absence of a fetal heartbeat when one should be present based on gestational age. It may also show an empty gestational sac or a fetal pole smaller than expected for the dates. Serial HCG measurements are often used with ultrasound findings.
While HCG levels alone cannot definitively diagnose a missed miscarriage, their trend can provide supporting evidence. If HCG levels are not rising appropriately or begin to decline after initially rising, it raises suspicion when combined with ultrasound findings. Healthcare providers interpret these results together to confirm the diagnosis.
Following a diagnosis, several management options are available, tailored to individual circumstances and preferences. Expectant management involves waiting for the body to naturally pass the pregnancy tissue, which can take days or weeks. Medical management uses medication, such as misoprostol, to expel the tissue. Surgical management, often a dilation and curettage (D&C) procedure, involves surgical removal of tissue from the uterus. Consulting with a healthcare provider is important to discuss these options.