Pregnancy Loss Symptoms and Diagnosis No Yolk Sac in Early Pregnancy Does It Mean Miscarriage? 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 October 23, 2021 Medically reviewed Verywell Family articles are reviewed by board-certified physicians and family healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Meredith Shur, MD Medically reviewed by Meredith Shur, MD Meredith Shur, MD, FACOG, is board-certified in obstetrics and gynecology, as well as a certified medical examiner. Learn about our Medical Review Board Print Table of Contents View All Table of Contents What Is the Yolk Sac? Miscalculated Due Date Sign of Miscarriage Empty Sac Pregnancy Each stage of pregnancy has characteristics that are fairly reliable indicators of whether the pregnancy is healthy and developing as it should. This is one reason why ultrasounds during pregnancy can be so valuable, even in the first weeks. Ultrasounds are routinely done around 6 weeks gestation. One of the things the doctor and technician look for is a yolk sac. When this vital structure doesn't appear to be there, the most likely reason is that the pregnancy isn't viable—in other words, that a miscarriage has occurred. However, this isn't always the case. If you're newly pregnant and the yolk sac isn't visible on your six-week ultrasound, it may simply mean you aren't as far along as you thought. First Trimester Ultrasound: What to Expect What Is the Yolk Sac? In early pregnancy, the yolk sac functions as a source of nourishment for the developing fetus. It's the first structure to be visible within the gestational sac, which envelopes the developing fetus and the amniotic fluid. The gestational sac looks like a white rim around a clear center. It can be seen on a transvaginal ultrasound— a procedure in which the ultrasound wand is inserted into the vagina rather than pressed against the abdomen—between 3 and 5 weeks gestation. The yolk sac isn't visible until around 5 weeks gestation when using an abdominal ultrasound. The yolk sac provides nutrition to the developing embryo until the placenta takes over. That's why it's a good indicator of the health of the pregnancy. Miscalculated Due Date Occasionally, not seeing a yolk sac on an ultrasound at this stage of pregnancy could simply mean the gestational age may have been miscalculated. This can happen if you made an error in remembering when your last period was or if you have irregular menstrual cycles. When a doctor suspects incorrect gestational age in a person who was believed to be around 6 weeks pregnant but has no yolk sac, they usually recommend doing another ultrasound in a week or two. By then, if all is well and the pregnancy is viable, the yolk sac and possibly the fetal pole (a curved structure that will eventually develop into the baby) will be visible. What's Going On? No yolk sac at 6 weeks of gestation may mean either that the pregnancy is less than 6 weeks along or there has been a miscarriage. Having another ultrasound in one to two weeks can determine if the pregnancy is viable or not. Sign of Miscarriage Often, seeing no yolk sac (or a yolk sac that is smaller than normal or otherwise misshapen) at 6 weeks can be a sign of miscarriage. Unfortunately, you'll most likely have to wait until a follow-up ultrasound to be sure. At that time, if the ultrasound does not show continued development of the pregnancy and there's still no visible yolk sac, your doctor will diagnose a miscarriage. You won't always have to wait to know for sure, however. Sometimes, if the gestational sac is a certain size (25 millimeters or more) on the first ultrasound and there is no yolk sac or embryo, your doctor will be able to diagnose a miscarriage right away. First Trimester Miscarriages Empty Sac Pregnancy When the gestational sac is empty (meaning there's no yolk sac or embryo by the time that there should be), this is known as an empty sac pregnancy. Other terms for an empty sac pregnancy are an "anembryonic" pregnancy or a blighted ovum (a term that's now considered to be outdated). An empty sac pregnancy is a type of miscarriage, even though the products of conception are still contained in the uterus. If this happens to you, you may be given the choice of letting nature take its course or having a procedure called dilation and curettage (D&C). A D&C involves dilating the cervix to create an opening for a thin surgical instrument to remove tissue from the uterus. Early Miscarriage D&C: What to Expect Research shows that empty sac pregnancies frequently have chromosome abnormalities. It's believed that the body recognizes the problem early on and stops further progress of the pregnancy. An empty sac diagnosis may feel cruel, but it may help to think of it as nature's way of keeping unhealthy pregnancies from continuing. Questions to Ask Your Doctor After Pregnancy Loss A Word From Verywell Not seeing the yolk sac at the pregnancy confirmation appointment can be scary and very disappointing. Remember, the timing might be off, so you could still be pregnant. Other times, the yolk sac is absent due to a miscarriage. No matter how early you are in your pregnancy, learning that the fetus is not viable can be very upsetting. But rest assured that early miscarriages are very common, often happening before someone even knows they're pregnant—and having had one in no way indicates that you won't carry to term next time. Can You Get Pregnant Right Away After a Miscarriage? Was this page helpful? Thanks for your feedback! Get diet and wellness tips delivered to your inbox. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 6 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. Donovan MF, Bordoni B. Embryology, Yolk Sac. StatPearls Publishing. 2021. Gaillard F. Gestational Sac. Radiopaedia. Last Revised September 20, 2021. Condous G. Ultrasound Diagnosis of Miscarriage: New Guidelines to Prevent Harm. Australasian Journal of Ultrasound in Medicine. 2011;14(4):2. doi: 10.1002/j.2205-0140.2011.tb00127.x Chaudhry K, Tafti D, Siccardi MA. Anembryonic Pregnancy. StatPearls Publishing. 2021. Cleveland Clinic. Dilation and curettage (D&C): Treatment, Risks, Recovery. Reviewed March 15, 2021. Pal AK, Ambulkar PS, Waghmare JE, Wankhede V, Shende MR, Tarnekar AM. Chromosomal Aberrations in Couples With Pregnancy Loss: a Retrospective Study. Journal of Human Reproductive Sciences. 2018;11(3):247-253. doi: 10.4103/jhrs.JHRS_124_17 Additional Reading American College of Obstetricians and Gynecologists. Dilation and curettage. Updated March 2019. Doubilet PM, Benson CB, Bourne T, et al. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med. 2013;369(15):1443-51. doi:10.1056/nejmra1302417 Moradan S, Forouzeshfar M. Are abnormal yolk sac characteristics important factors in abortion rates? Int J Fertil Steril. 2012;6(2):127-130.