The medical term “threatened abortion” is a specific diagnosis used by healthcare providers to describe a common complication in early pregnancy. It occurs when a pregnant person experiences vaginal bleeding before the 20th week of gestation. This diagnosis indicates that pregnancy loss is possible, but not certain, and the pregnancy may continue successfully.
The Clinical Definition
Threatened abortion is defined by the presence of vaginal bleeding or spotting before the 20th week of pregnancy, usually occurring within the first trimester. The key criterion separating this diagnosis from other early pregnancy complications is the status of the cervix. In a threatened abortion, a physical examination confirms that the cervical os, the opening to the uterus, remains closed.
This closed cervix is a positive finding because it confirms that pregnancy loss has not become inevitable. The diagnosis also requires that the embryo or fetus still be viable, meaning an ultrasound shows it is alive, often with a detectable heart rate. This combination of bleeding, a closed cervix, and a viable pregnancy defines the situation as “threatened,” distinguishing it from inevitable or complete miscarriage.
Recognizing the Signs
The most common sign of a threatened abortion is vaginal bleeding, which varies significantly. This bleeding may be very light, appearing as spotting or a brownish discharge, or it may be heavier, similar to a light menstrual period. Bleeding heavier than a typical menstrual flow is generally associated with an increased risk of the pregnancy not continuing.
Another common symptom is mild abdominal discomfort or cramping, which can feel like period pain. This cramping is usually intermittent and may also be felt as lower back pressure. If the cramping becomes severe or the bleeding becomes excessive, it may indicate the status is changing to a more advanced type of pregnancy complication.
Diagnostic Procedures and Next Steps
The immediate goal of a healthcare provider is to confirm the diagnosis and rule out more serious conditions. A pelvic examination is performed to assess the source of the bleeding and confirm that the cervical os remains closed. If the cervix is open, the diagnosis immediately shifts to an inevitable or incomplete miscarriage.
The most informative diagnostic tool is the transvaginal ultrasound, used to establish the pregnancy’s location and viability. The ultrasound confirms the pregnancy is inside the uterus, ruling out an ectopic pregnancy, and checks for a fetal heartbeat. Blood tests also measure the level of human chorionic gonadotropin (HCG), often with repeat measurements to ensure the level is rising appropriately.
Once the diagnosis is confirmed, the typical medical recommendation involves expectant management and close monitoring. There is generally no specific treatment proven to stop the bleeding or prevent a miscarriage. Advice often includes avoiding strenuous activities, refraining from sexual intercourse (pelvic rest), and monitoring changes in bleeding or cramping. Patients are instructed to return immediately if bleeding increases substantially or if severe pain develops.
Understanding the Prognosis
Despite the anxiety the term causes, a significant number of pregnancies diagnosed as a threatened abortion continue successfully. Studies show that approximately 75% to 80% of these cases ultimately result in a full-term birth, especially when a fetal heartbeat is confirmed early on. The presence of a fetal heartbeat on the initial ultrasound is the best indicator for a positive outcome.
The prognosis is influenced by several factors, including the amount of bleeding, gestational age, and the presence of a subchorionic hematoma. A larger volume of bleeding or a large collection of blood behind the placenta (subchorionic hematoma) may increase the risk of the pregnancy not continuing.
While the majority of pregnancies continue, those who experience a threatened abortion have a slightly increased risk of later complications. These risks include a higher chance of preterm birth, premature rupture of membranes, and lower infant birth weight. The diagnosis serves primarily as a signal for increased monitoring throughout the remainder of the pregnancy.