Is an Ultrasound in the Doctor's Office Accurate?

Jane Foley's picture

QUESTION

Dear Ms Ultrasound,
I had my LMP on 3/16/04 and was seen by my doctor at 6 weeks from LMP to confirm pregnancy. On that day, the ultrasound showed a yolk sac and a week later he had me return for a repeat scan. On 5/6/04 he did a second transvaginal scan and this time had a very difficult time finding anything at first but finally he located the sac and saw the very blurry fetal pole next to it. The sac and pole seemed to be so close to the corner of uterus, that it was very hard for him to decipher the image but we did see "flickers" (three times he located the flickers) which the doctor described to be a heartbeat. The image, blurry as it was, he seemed to think measured 2-3mm.

He didn't seem very pleased with having such a difficult time locating it and left me very confused about the measurement. I had a m/c last year and have been trying to get pregnant until now. I am so worried and not sure what all of this information he saw means. Am I at risk for miscarriage? Should it have measured more than that at 7 weeks? I thought seeing the h/b was great and now I am not sure what to expect. Thank you for your time.

ANSWER

Hello. I can understand your anxiety having had a miscarriage in the past. I am always somewhat leery of ultrasounds done in doctor's offices. Usually the equipment does not produce the highest resolution and consequently cannot appreciate those early pregnancies well. Doctors most commonly buy a smaller unit just to confirm things like heartbeat, position of fetus etc. (Of course your doctor could have great equipment so I would not presume to know.) Having an ultrasound in a radiology department with a licensed Sonographer always makes me feel better when women write me about the results of their ultrasound.

Just last week I scanned a girl whose doctor told here he could not see anything in the gestational sac. When I took a look -- viola! There it was a normal heartbeat and fetal pole.

May I suggest to you to, take a deep breath, and release some of that anxiety. Early ultrasounds can produce a lot of unnecessary worry for many reasons:

  • Poor equipment
  • An inexperienced individual doing the ultrasound
  • Too early to see anything (which is the most common)
  • A problem with the pregnancy

Waiting to around 8 weeks with you for a rescan would probably be the right thing to do. If the doctor does not see a healthy fetal pole with a strong heartbeat, over 100 beats per minute, you will then know this pregnancy is probably not viable. Your doctor did see a heartbeat which is always a good sign!

A quick FYI (for your information), When you have your next ultrasound I am hoping your doctor finds the pregnancy has in fact implanted in the center of your uterus. If your doctor truly did find that the gestational sac was at the edge of the uterus he/she will have to rule out what is called a "cornual ectopic". This happens when the gestational sac implants at the opening of the fallopian tube and begins to grow there. It is not very common but is always something we think about when a gestational sac is eccentrically placed in the uterus and might be worth a mention at your next appointment.My advice to women in this situation is to try and remove yourself from the medical side of it all. Relax, connect with the life created inside you until it is time to have your next ultrasound.

-- Jane, RDMS