Fetal weight

[ericdamiansean]

Can you estimate fetal weight by corresponding it to the gestational age? In case you're asked in an exam, and are supposed to give an educated guess

For eg, a 24 week old fetus would weight about 2200-2400g, a 36 week would weight about 3500g?

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[fuzzyerin]

a 24 week fetus weighs closer to 500-700g. but yes, you can estimate "about how much a baby weighs" from the gestational age.

 

[DMBmatty08]

take a look at a pregnancy wheel, most have the corresponding weight in grams for the gestational age.

 

[tiredmom]

There are tables that are regionally specific (we grow big babies here in San Antonio!) The only weight I would guess you might be asked would be a 500 gm weight because less than 500 gms is likely not to be a viable baby, so the pedi's won't rescuscitate them (ET tubes are too small to ventilate). That's at about 24 weeks, give or take a bit.

 

[ericdamiansean]

take a look at a pregnancy wheel, most have the corresponding weight in grams for the gestational age.

I wish I could drag a pregnancy wheel with me into my clinical skills exam, that and also the immunization schedule, growth charts, developmental milestones etc.. I'm only allowed to bring a measuring tape, pen torch, 2 rulers, and a tendon hammer..and this applies for all rotations.

Anyway, I've sort of made up a formula, doesn't work all the time though. For anything from 20-29 weeks, minus 18 and add 2 zeroes behind the figure you get ie if 28 weeks (28-18=10 "00" grams)
From 30-35, minus 12, so at 32 weeks it would be about 2000g
From 36 onwards, minus 6
I did notice that the decrements are in 6s ie 18, 12 and then 6

Do not quote me for any exams though

 

[DoctorMom78]

LOL! Not if they are my monster babies! They were all REALLY big.

 

[tiredmom]

On physical exam - if you picture a 1 L IV bag - guesstimate how many Iv bags big the baby is and each bag is 1000 grams. Why are you needing to come up with this info on a clinical skills exam?

 

[ericdamiansean]

LOL! Not if they are my monster babies! They were all REALLY big.

And I'm thinking it's cos someone's big (just kidding)

On physical exam - if you picture a 1 L IV bag - guesstimate how many Iv bags big the baby is and each bag is 1000 grams. Why are you needing to come up with this info on a clinical skills exam?

Estimating the correct weight range would probably give me 1 point (out of 10) for that station

 

[BayAreaOB]

For clinical EFW (on physical exam).
Think of a 5# bag of sugar. 1.5 bags width is about 7.5#, 2 bags about 9-10#. It takes a while to get good at this. As an intern, I did it this way for all my admits and then checked the actual birthweight and I got pretty good!

Good luck on you exams

 

[ericdamiansean]

Passed!!

 

[DoctorMom78]

And I'm thinking it's cos someone's big (just kidding)

Congrats on passing the test!

I am actually about average weight and have no history of gestational diabetes. I only gained about 15 pounds in each pregnancy and ended up leaving the hospital weighing less than before I got pregnant. But, my second child was 10 lbs 5 oz (delivered one week past my due date). My third was 8 lbs 2 oz at 38 weeks exactly. My fourth was 8 lbs 3oz at 35 weeks and 6 days!!!! She would have been a record breaker I think! I blame my husband!

They are still big kids; not fat, but off the charts for their heights and 95% for their weights. They "estimated" my 10lb 5oz baby to be about 8 1/2 pounds. So, the point is that the "estimate" is really not so reliable in the real world because a lot of things influence fetal weight.

 

[ericdamiansean]

Thanks

I totally agree on that, if you're in obgyn long enough, you'll definately be seeing some grossly wrong estimates.

But delivering such big babies, hats off to you