Looking for help calculating whether SGA babies are symmetrical or asymmetrical

[PokerDoc]

Hi everyone. I am a medical student going into Radiology and I know nothing about obstetrics aside from 3rd year rotation stuff. I am doing a research study and part of my data compiling requires me to differentiate whether certain small for gestational age babies are symmetrical or asymmetrical at birth.

Since it would take me months to go over the charts of the 500 cases I have already reviewed, I was wondering if anyone here could cite me a formula using the data I already had to determine this.

for each baby I have: gestational age, birth weight, length, and head circumference.

Is there any way to do this without going back over 500 charts and hunting down the data myself?

Thanks so much!

---

Members don't see this ad.

 

[wannabeOBGYN]

Hi everyone. I am a medical student going into Radiology and I know nothing about obstetrics aside from 3rd year rotation stuff. I am doing a research study and part of my data compiling requires me to differentiate whether certain small for gestational age babies are symmetrical or asymmetrical at birth.

Since it would take me months to go over the charts of the 500 cases I have already reviewed, I was wondering if anyone here could cite me a formula using the data I already had to determine this.

for each baby I have: gestational age, birth weight, length, and head circumference.

Is there any way to do this without going back over 500 charts and hunting down the data myself?

Thanks so much!

I read an ACOG bulletin about IUGR the other day that discussed that stuff. I don't remember if it had a formula or the number of the bulletin, but it's something to look for perhaps?

 

[ScubaStarved]

Hi everyone. I am a medical student going into Radiology and I know nothing about obstetrics aside from 3rd year rotation stuff. I am doing a research study and part of my data compiling requires me to differentiate whether certain small for gestational age babies are symmetrical or asymmetrical at birth.

Since it would take me months to go over the charts of the 500 cases I have already reviewed, I was wondering if anyone here could cite me a formula using the data I already had to determine this.

for each baby I have: gestational age, birth weight, length, and head circumference.

Is there any way to do this without going back over 500 charts and hunting down the data myself?

Thanks so much!

Forgive me if this is too basic: you'll recall from your rotation that symmetric vs. asymmetric growth restriction is a distinction made by comparing the fetus HC/AC ratio to a nomogram, which corrects for GA. I did 10 minutes of reading, including from the online Williams text, and I could not find any other validated systems for making this distinction.

In short, I think you need AC and I hope that you're using EMR.

Here is a link to a free, recent-ish article (nomogram is Fig 1) which may be of assistance to you. It's cited by Williams and much primary literature:
http://journals.lww.com/greenjourna..._symmetric_and_asymmetric_fetal_growth.1.aspx

 

[Global Disrobal]

This is an oversimplified answer, but should suffice in getting you started on your data collection. I would still suggest meeting with your research mentor to review these facts to ensure it is in line with your hypothesis and variables of interest.

A growth restricted newborn is:

- Asymmetric if length is normal for gestational age and weight is below normal*
- Symmetric if both length and weight are normal*
*Meet with your mentor to define abnormal (less than 10th, 5th, or 3rd percentile). In practice, we use 10th.

You can also use the Ponderal Index, but it is less useful and has many dependent variables.

Good luck!

 

[PokerDoc]

Thanks guys, very helpful!

 

[oldbearprofessor]

For babies born in the US, I recommend plotting percentiles off the Olsen data.

The accuracy of your data will depend in part in how birth lengths were measured in your cohort. If not done with a measuring board per WHO standards, the data will be more difficult to interpret and you should also look at the FOC data.

Note that since you have data post-delivery, not in utero data, it would not be usual to look at in utero abdominal circumference to determine SGA status, etc. You have the data you need.

finally, if you wish to batch analyze, consider becoming friends with a program called EpiInfo, but that would use a slightly different dataset than the Olsen curves.

 

[Global Disrobal]

Ditto. Epi Info is a great program and got me through fellowship for most analyses except the advanced stuff.