Pregnancy Loss Symptoms and Diagnosis Diagnosing Miscarriage by Ultrasound By Krissi Danielsson Krissi Danielsson Krissi Danielsson, MD is a doctor of family medicine and an advocate for those who have experienced miscarriage. Learn about our editorial process Updated on December 10, 2020 Medically reviewed by Brian Levine, MD, MS, FACOG Medically reviewed by Brian Levine, MD, MS, FACOG Brian Levine, MD, MS, FACOG, is board-certified in obstetrics-gynecology, as well as reproductive endocrinology and infertility (REI). He is the director and founding partner of CCRM New York and was named a rising star by Super Doctors from 2017 to 2019. Learn about our Medical Review Board Print webphotographeer / Getty Images Table of Contents View All Table of Contents Diagnosing Miscarriage How Guidelines Vary Ultrasound Is Uncertain Calculating Miscarriage Risk Experiencing Miscarriage Resources If you're concerned that you may be miscarrying, you may wonder how a miscarriage is diagnosed. How can ultrasound help to determine if you are having an early pregnancy versus a missed miscarriage, and what are the limits of this test in early pregnancy? Diagnosing Miscarriage With Ultrasound When administering an early ultrasound exam, such as during the first trimester of a woman's pregnancy, it can be hard for medical professionals to distinguish an early pregnancy from a missed miscarriage. A missed miscarriage is a pregnancy loss in which the embryo has either stopped developing or was never formed, but the mother is not yet having clear miscarriage symptoms such as vaginal bleeding or spotting, the passing of tissue through the vagina, and/or pain or cramping in the abdomen, lower back, or pelvic area. To avoid a misdiagnosis, doctors use specific guidelines to determine when ultrasound results may signal a miscarriage. For example, in a report by the Society for Obstetrics and Gynecology of Canada, researchers recommended that miscarriage is diagnosed if a trans-vaginal ultrasound reveals the following: Gestational sac is larger than 8mm and has no yolk sac Gestational sac is larger than 16mm and has no embryo No heartbeat in an embryo larger than 5 mm In addition, if an earlier ultrasound revealed a fetal heartbeat and a subsequent ultrasound finds no heartbeat, this also indicates a miscarriage. Falling levels of hCG (human chorionic gonadotropin, a hormone that's made during pregnancy) alongside an ultrasound that shows an empty gestational sac or no fetal heartbeat may also lead to a miscarriage diagnosis. Symptoms of a Missed Miscarriage How Guidelines Vary It's critical to note that different countries and different medical associations may vary in their exact approaches to the issue of distinguishing an early pregnancy from a missed miscarriage. And, of course, as scientific research on the topic evolves, guidelines may change. The reason that guidelines such as these are important is that most pregnancy losses occur in the first trimester. In addition, there are several situations which can make it more difficult to make the distinction. In other words, there are several situations which can increase the risk of a misdiagnosis. These can range from an inaccurate estimation of your due date to a vanishing twin, a condition in which one twin is miscarried while the other remains alive. What If Your Ultrasound Is Uncertain? In following the ultrasound guidelines for diagnosing a miscarriage, there will be many times when the ultrasound cannot conclusively say if you have an early pregnancy or a missed miscarriage. In order to avoid the possibility of a misdiagnosis, your doctor may recommend waiting and repeating an ultrasound in a week. In a normal pregnancy, the gestational sac (and embryo if seen) should be significantly larger in one week, whereas a missed miscarriage will show no growth or only minimal growth. During this week, if you have a missed miscarriage instead of an early pregnancy, you may develop symptoms of a miscarriage. It may be helpful to familiarize yourself with the most common signs and symptoms of an early miscarriage. How to Cope With Abnormal Ultrasound Results Calculating Miscarriage Risk Calculating a mother's risk of pregnancy loss depends largely on her age. According to the American College of Obstetricians and Gynecologists, the risk of miscarriage for women changes significantly with age. The Woman's Age Average Risk of Miscarriage 20-30 years old 9-percent to 17-percent 35 years old 20-percent 40 years old 40-percent 45 years old 80-percent If You Experience a Miscarriage If you do experience a missed miscarriage, which can be extremely traumatic (both physically and emotionally), there are resources available that can help you and your partner get through this difficult period. Ask your doctor if there are any in-person support groups in your area, and/or seek out anonymous online support in one of the many online miscarriage support groups or support communities. You can also check out online resources like Miscarriage Matters, a site run by a charitable organization that offers online live chats. Miscarriage Resources If you're just hearing about missed miscarriages and more, you may be feeling confused about all of the terminology used to describe miscarriages, for example, terms such as a blighted ovum, a chemical pregnancy, a molar pregnancy, and more. Ask questions. If you don't understand something your obstetrician is saying, ask her to explain it in a different way. Wondering about the possibility of miscarriage, or coping with a miscarriage, is difficult enough when you are able to understand the medical lingo. It can be even more frightening if you feel like you are listening to a foreign language. Here are some answers to the questions people often ask with first trimester miscarriages but write down any questions you have so that you remember to ask. Answers won't bring back a baby lost to miscarriage but may help you as you cope in the weeks and months to follow. Coping With Miscarriage in the First Trimester 3 Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Morin L, Cargill YM, Glanc P. Ultrasound Evaluation of First Trimester Complications of Pregnancy. J Obstet Gynaecol Can. 2016;38(10):982-988. doi:10.1016/j.jogc.2016.06.001 Barnhart K, Sammel MD, Chung K, Zhou L, Hummel AC, Guo W. Decline of serum human chorionic gonadotropin and spontaneous complete abortion: defining the normal curve. Obstet Gynecol. 2004;104(5 Pt 1):975-81. doi:10.1097/01.AOG.0000142712.80407.fd The American College of Obstetricians and Gynecologists. ACOG Practice Bulletin. Additional Reading Ashoush, S., Abuelghar, W., Tamara, T., and D. Ajiobboury. Relation Between Types of Yolk Sac Abnormalities and Early Embryonic Morphology in First-Trimester Missed Miscarriage. Journal of Obstetric and Gynaecology Research. 2016. 42(1):21-8. Morin, L., Cargill, Y., and P. Glanc. Ultrasound Evaluation of First Trimester Complications of Pregnancy. Journal of Obstetrics and Gynaecology Canada. 2016. 38(10):982-988. By Krissi Danielsson Krissi Danielsson, MD is a doctor of family medicine and an advocate for those who have experienced miscarriage. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies