Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up


All communities will be placed in read-only mode (you will be able to see and search for posts but not start or reply to discussions) as we conduct maintenance. We will make another announcement when posting is re-opened. Thank you for your continued support and patience, and if you have any further questions, please email

Yours in health,
WebMD Community Management

Includes Expert Content
Two Yolk Sacs, 1 Gestational Sac
KMS2010 posted:
I am 8 weeks pregnant. Last week, I had my first ultrasound at exactly 7 weeks. They stated that it looks like I had a blighted ovum. They saw one empty yolk sac. We decided to wait one more week and do another ultrasound before having a D&C.

Yesterday we had quite a shock. There were now 2 yolk sacs in the same gestational sac, one of which was bigger than the other. We still did not see the embryos. The radiologist said it was very rare to see this and was inconclusive as to the viability of the pregnancy. As such, we decided to wait and look again in one more week.

Why is one yolk sac so much smaller than the other and is there still hope that it (or even the larger yolk sac) may have a developing baby?
Jane Harrison Hohner, RN, RNP responded:
Dear KMS: Alas, I am not a perinatologist so this will be a more general answer. As you likely know the gestational sac appears at about 4-5 weeks followed by the appearance of the yolk sac. That you have still not seen an embryo or cardiac motion does suggest a blighted ovum. For a good overview on the ultrasound assessment of pregnancy check this link:

After reviewing MULTIPLE studies at the National Library of Medicine site, this seemed to best address discordant yolk sac size:

Radiology. 1992 Apr;183(1):115-8.
Yolk sac diameter and shape at endovaginal US: predictors of pregnancy outcome in the first trimester.

Lindsay DJ, Lovett IS, Lyons EA, Levi CS, Zheng XH, Holt SC, Dashefsky SM.

Department of Radiology, Health Sciences Centre, Winnipeg, Man, Canada.

Four hundred eighty-six consecutive women who underwent endovaginal sonography when their fetuses were less than 10 weeks menstrual age (MA) were evaluated to establish the normal size and shape of the secondary yolk sac (YS) and to assess the value of YS measurement in predicting pregnancy outcome in the first trimester. A YS diameter more than two standard deviations (SDs) above the mean when compared with the mean gestational sac diameter allowed prediction of an abnormal pregnancy outcome with a sensitivity of 15.6%, a specificity of 97.4%, and a positive predictive value of 60.0%. A YS diameter more than two SDs below the mean allowed prediction of an abnormal outcome with a sensitivity of 15.6%, a specificity of 95.3%, and a positive predictive value of 44.4%. No pregnancy with a normal outcome had a YS diameter of greater than 5.6 mm at less than 10 weeks MA. In six patients, the YS diameter was greater than 5.6 mm. All six had an abnormal outcome. Of seven patients with abnormal YS shape at initial sonography, three had abnormal YS shape at follow-up examinations. All three had an abnormal outcome.

It sounds like your OB is being very thorough. I hope the next ultrasound will help to clarify your situation.

In Support,
An_193332 replied to Jane Harrison Hohner, RN, RNP's response:
have 1 question is it possibal if ther is pregnency with 3 chiled at a time we can remove one & left 2 for birth ,till what time it is safe & is ther any chance to harm other 2
cozmos responded:
hi km i hope ur well, this post is so old lol.
id like to know what your outcome was for the pregnancy u speak of as im in exactly the same sitiuation. id been scanned from 6.5 weeks and had to go back a week later as there was no fetal pole, the yolksac was large, went back the next week, still no fetal pole and yolk sac measured 9 mm. booked a dnc for the following week.
they scanned me before the dnc and discovered the original yolksac had shrunk and looked normal and there was another one a bit smaller on the other side of the sack???. needless to say everyone was baffled so the dnc was cancelled and im to wait another week to see if theres any change, iv been told not to get my hopes up. i should be 8 weeks now, i know there should be evidence of fetal activity now its just very strange i hope u can help enlighten me with good or bad news of ur outcome . many thanks x

Helpful Tips

I am having heavy bleeding and sever pain with it every month that it affects my daily living when I have it I even had to drop out of ... More
Was this Helpful?
16 of 27 found this helpful

Expert Blog

Below the Belt: Women's Health - Jane Harrison-Hohner, RN, RNP

From HPV to irregular periods to PMS to fibroids, Jane Harrison-Hohner, RN, is here to share her knowledge and insight...Read More

Report Problems With Your Medications to the FDA

FDAYou are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.