Are My Ultrasound Measurements in the Normal Range?

QUESTION

Dear Ms. Ultrasound,
My ultrasound measurements today at 33 weeks and 3 days were: AC - 250.9 mm HC - 289.4 Femur - 60.8

I was just wondering if these were normal as they seem small to me. My doctor isn't worried and says it's well within normal. He has asked to re-scan me in 2 weeks and if the growth has slowed again he will take baby out. The growth has slowed a bit from 30 weeks.

Is it normal to wait 2 weeks with baby not growing well?? Do babies like this ever stop growing?? Will it be ok to wait 2 weeks??

They also checked the placenta on a doppler flow and said it seemed ok. I am not sure what that means.

I am tiny size 6 uk, before pregnancy and barely 5 foot and baby is weighing 1.5 kgs. Does this mean baby healthy just little like me?

ANSWER

Hello,
When measuring a fetus in the third trimester, the error ratio can be up to 2 weeks off and be quite normal. This means, for example that you may be 35 weeks and measure 33 weeks and it is normal. Many factors play into the measurements from mother's body-type, genetics, the sonographer who is doing the exam, to the calculation package chosen in the ultrasound machine.

It is normal for the doctor to give the fetus time to grow before checking again. Two weeks is fine. As long as you are growing the doctor will be happy. It sounds to me like your doctor is not too worried. He/she is being cautious by checking you again and has made a plan for you and your baby if the growth has stopped.

Since you are such a tiny little bit, I would not expect you to have a large baby. I think you and your measurements are fine for now. Relax. Take good care of yourself, your hydration, nutrition and peace of mind. This will give your baby the best chance possible.

With regards,
-- Jane RDMS

Jane Foley

Jane Foley has worked as a Sonographer (Ultrasound Technologist) since 1979. Jane has lived and worked in many parts of the world including Saudi Arabia. She is a Registered Diagnostic Medical Sonographer or RDMS. She pulls a wealth of information from her experience in the field of Radiology and her interactions with such a broad cross-section of cultures she has visited. She now makes her home on the island of Maui with her English husband, Michael.