Maternal Weight
I am currently wrestling with the question of the influences of maternal weight, weight gain and BMI on birth weight- again.
Thanks to the consultant obstetritian who appears in my office like Monty Python's Spanish Inquisition - usually when I'm watering the pot plant, answering email or halfway through a packed lunch - never when I'm looking like I know anything about clinical nutrition- I've been looking for reliable ways to assess women's body composition in pregnancy.
Mid-upper arm circumference is useful as it is closely associated with prepregnancy weight and stays relatively constant, so the stage of gestation is less relevant than for weight. But without a triceps skinfold to estimate fat, it's probably more useful to assess undernutrition than overweight / obesity. Should I just do triceps skinfolds?? So difficult to get accurate measurements and needs the same observer to take measurements for it to have any validity.
Centile growth charts for height go up to age 20 so should be ok for adults...but the sample size of 20 year olds that they're based on was tiny, so I think national averages are more representative.
The norms for BMI don't cover pregnancy anyway - we look at pre-pregnancy BMI and percentage weight change based on individual requirements as a guide for women. But BMI is simple and universal......
Bioelectrical impedence is not of value in pregnancy - surely confounded by the amniotic fluid...... and on I go.
Probably just need to stick with weight/height.....or BMI and MUAC....or measure the lot and see what outcomes are like for an Irish population.(Sigh) More 12 hour days ahead. Lucky that I'm interested in my job.
Probably need to sleep on it and clear my head.
Thanks to the consultant obstetritian who appears in my office like Monty Python's Spanish Inquisition - usually when I'm watering the pot plant, answering email or halfway through a packed lunch - never when I'm looking like I know anything about clinical nutrition- I've been looking for reliable ways to assess women's body composition in pregnancy.
Mid-upper arm circumference is useful as it is closely associated with prepregnancy weight and stays relatively constant, so the stage of gestation is less relevant than for weight. But without a triceps skinfold to estimate fat, it's probably more useful to assess undernutrition than overweight / obesity. Should I just do triceps skinfolds?? So difficult to get accurate measurements and needs the same observer to take measurements for it to have any validity.
Centile growth charts for height go up to age 20 so should be ok for adults...but the sample size of 20 year olds that they're based on was tiny, so I think national averages are more representative.
The norms for BMI don't cover pregnancy anyway - we look at pre-pregnancy BMI and percentage weight change based on individual requirements as a guide for women. But BMI is simple and universal......
Bioelectrical impedence is not of value in pregnancy - surely confounded by the amniotic fluid...... and on I go.
Probably just need to stick with weight/height.....or BMI and MUAC....or measure the lot and see what outcomes are like for an Irish population.(Sigh) More 12 hour days ahead. Lucky that I'm interested in my job.
Probably need to sleep on it and clear my head.
posted by TheDietitian at 9:46 p.m.
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