search:

Re: Baby measuring small for dates

From: Dr. (anonymous@obgyn.net)
Thu, 24 Jun 1999 04:14:28 -0500 (CDT)


Dear Melinda

Ultrasound measurements have an error in the technique. It would be normal practice NOT to challenge the dates if the USS measurements were less than 2 weeks different from the menstrual dates. At 18-22 weeks a normal measurement of the head or thigh bone is accurate for dating to about plus or minus 2 weeks. A baby length (CRL)at 12 weeks is accurate to about +/- 10 days. After 24 weeks measurements are +/- FOUR weeks.

So the later the scan the less accurate the scan dates are. Certainly in my practice we would not change dates unless two scans before 22 weeks show a greater than 2 week difference from the menstrual dates.

On the conception issue .... remember that conception does not equal intercourse or vice versa! The egg hangs around for about 24 hours but sperm can hang around longer. Timing of egg production is therefore useful (but not definite) but timing of sex isn't when it comes to dating a pregnancy.

On the issue of chromosome abnormalities don't worry ....get some more accurate info ....see an Obstetrician and I'm sure they will reassure you.

--
Ross Welch
Consultant in Fetomaternal medicine
Duchess of Westminster Wing
Arrowe Park Hospital
Upton, Wirral.
UK





recommended search...
Google
OBGYN.net forums endometriosis zone Web

use when must restrict search to only the pregnancy & birth forum...
Enter search keywords:
Returns per screen: Require all keywords:
Return to [ Pregnancy & Birth Forum ] Report TECHNICAL Problems ONLY to: webmaster@obgyn.net
Last Updated: Mon May 19 17:29:03 2008

home | medical professionals | women | industry | forums | international
e-mail | about us | advertising | our sponsors | contact us | disclaimer |

This information is provided for educational purposes only.
Please read the disclaimer. ©1996-2008, all rights reserved.
Do not reproduce without permission of MediSpecialty.com