Miscarriage is commonly diagnosed using a combination of tests, the most standard of which include the hCG blood test, an ultrasound, fetal heart scanning, and a pelvic exam.
Quantitative hCG Blood Test
Human chorionic gonadotropin (HCG) is a hormone produced by the body during pregnancy. It becomes detectable in your about a week after ovulation when the fertilized egg implants in the uterus. In the early weeks of pregnancy, the level of hCG can double every two to three days. When it is not increasing appropriately, this can often be an indication of a miscarriage. Almost invariably, falling hCG levels are enough to tell you that there’s a problem. To confirm a diagnosis, doctors will need at least two hCG levels taken at least two days apart for results to be useful. While helpful in later pregnancy, the usefulness of an hCG test decreases as the pregnancy progresses. In fact, by the time a heartbeat is detectable, an ultrasound will be far more useful in evaluating the pregnancy.
Ultrasound Scans
Ultrasound machines use sound waves to get a rough image of the fetus and gestational sac. In early pregnancy, until around week eight, most practitioners will use a transvaginal ultrasound, which is inserted into the vagina, rather than an external abdominal ultrasound. With the ultrasound, a miscarriage may be diagnosed under the following circumstances:
There are visible abnormalities or the lack of development of the gestational sac.There is a lack of a fetal heartbeat that was previously seen.The embryo does not have a heartbeat when larger than 5 millimeters in size.
These parameters can vary and often need to be supported by additional tests. It could be, however, that ovulation occurred later in the menstrual cycle and that the pregnancy was not as far along as the doctor had believed. Even being off by a few days can make a difference in how an ultrasound is interpreted.
Fetal Heart Rate Monitors
Fetal heart rate monitors, sometimes called fetal dopplers, are handheld ultrasound devices that solely detect the sound of your baby’s heart through your abdomen. Typically speaking, the heartbeat becomes audible on a fetal monitor somewhere between the seventh and 12th week of gestation. The exact time can vary based on the position of the uterus, the position of the placenta, and numerous other factors. In the early stage of pregnancy, the lack of a heartbeat may not be considered conclusive of a miscarriage. By contrast, after 12 weeks, it is a strong indication of a pregnancy loss. A full ultrasound will typically be ordered if the fetal heartbeat cannot be found.
Pelvic Examination
A doctor may include a pelvic exam as a part of the diagnosis to check whether the cervix is dilating. A dilated cervix is usually a strong indication that a woman is miscarrying. If there is spotting or light vaginal bleeding and the cervix is not dilating, this may suggest a threatened miscarriage, a relatively common condition in which the pregnancy is still viable. In most cases, the doctor will send the woman home and monitor her condition closely. Because spotting in early pregnancy is not uncommon, the doctor may choose to hold off additional testing unless the bleeding persists.
A Word From Verywell
Vaginal bleeding and cramping during pregnancy don’t necessarily mean that you’re having a miscarriage. In most cases, you and your baby will be just fine, and you will deliver on time without any complications. It is important to not ignore your symptoms, even if you’re not absolutely certain about what you’re experiencing. Whatever the cause, minor or serious, it’s best to get it looked earlier rather than later. Early diagnosis allows for fewer complications.
