When an Early Ultrasound Doesn't Show the Embryo

November 08, 2009

SEARCH drSpock

my account | sign in

HOT TOPICS

		Pregnancy Symptoms
		Read with Your Kids -- It's Fun!
		Take Our Quizzes
		Play with Your Baby

TOPICS


	Parents are talking about their children. Join the discussion.

When an Early Ultrasound Doesn't Show the Embryo

by Marjorie Greenfield, M.D.
reviewed and revised by Marjorie Greenfield, M.D.

For just about any pregnant couple, an ultrasound is a momentous event on the path to parenthood. But sometimes an early first-trimester ultrasound fails to show the embryo in the uterus, a confusing and often alarming situation.

Early ultrasound
Not everyone needs an ultrasound in the first trimester; in fact, most women don't have one. While some doctors perform these scans routinely, most practitioners reserve them for high-risk situations--when a woman has had some bleeding, for instance, or when she is at risk for an ectopic pregnancy.

What ultrasound can and can't see
Ultrasound creates an image by bouncing sound waves off surfaces. It can "see" things that are small, but it is not a microscope and can't get clear images of structures that are very tiny or those that are mixed in with the intestines or hidden deep in the pelvis. Healthy pregnancies are often easy to see because the uterus creates a frame around the amniotic sac, signaling its location. The same size sac in the fallopian tube or out near the ovary might not be easily detected. Transvaginal ultrasound, which can get a bit closer to the uterus, allows a healthy pregnancy to been seen about three to four days earlier than a transabdominal scan.

Reasons why the embryo may not be visible
If the ultrasound technician can't spot the embryo during an ultrasound, there are several possible reasons:

It's too early in the pregnancy. The pregnancy may be so early that the fetus is just too small to see. This usually means less than five and a half post-menstrual weeks, which is three and a half weeks from conception. If there is reason to believe that the pregnancy is this early, a repeat scan or two blood tests measuring the pregnancy hormone hCG taken 48 hours apart can help establish that the pregnancy is developing properly.

A miscarriage may have occurred. Sometimes the pregnancy can't be seen because it has stopped growing. This is medically referred to as a "blighted ovum." Often, a small collapsed amniotic sac can be seen. While it is sometimes quite apparent on ultrasound that there is no hope, there are occasions in which it isn't clear whether the pregnancy is just too early to see or if it is truly lost. If necessary, serial blood tests or another ultrasound a few days later will find the truth. The waiting can feel like torture, but even if it becomes clear that the pregnancy is gone, many expectant parents feel more settled knowing that there was no question about the findings.

There may be an ectopic pregnancy. Sometimes an embryo fails to migrate to the uterus after fertilization and stays in the fallopian tube. This is known as an ectopic, or tubal, pregnancy, and it is a medical emergency. Ectopic pregnancies can be hard to see on ultrasound because they are generally small and located adjacent to the intestines and ovaries. If your physician suspects an ectopic pregnancy, he will takes steps such as blood tests, repeat ultrasounds, or laparoscopy (telescopic surgery) to diagnose and treat the condition within a day or two.

The emotional toll
The finding that a pregnancy may not be progressing as you had hoped can lead to feelings of anxiety, hopelessness, fear, sadness, desperation, or anger--or any combination thereof. While ultrasound is helpful in collecting information to help clarify the situation, it can also put you face-to-face with bad news in an unfamiliar clinical setting without your family members or your practitioner. Sometimes the ultrasound staff can't give you information because they don't know your medical situation or what the next step would be in your care. In this case, they may refer you back to your practitioner, which can feel like a cruel delay when you are worrying. While doubts and fears may be causing you great pain, keep in mind that the destiny of this pregnancy is already determined. You need resolution of the questions for your grieving to begin or for your peace of mind, but there is nothing at this point that you can do to change fate. When you get home, gather those around you who can give you sustenance and support in the coming days.


RELATED INFORMATION

			What Ultrasound Can Show You During Pregnancy
			Ectopic Pregnancy
			Miscarriage
			Ultrasound in Pregnancy

Created June 21, 2001
Reviewed and revised July 27, 2004

| |
| | |

THIS SITE DOES NOT PROVIDE MEDICAL ADVICE. The information drSpock.com provides is for educational purposes only and is not a substitute for professional medical advice. Always seek the advice of your health care professional if you have a specific health concern. Mention or advertisement of any product, service, or brand does not constitute endorsement, guarantee, or recommendation by The Dr. Spock Company. Please read our full Terms of Service.