Determinants of valid estimation of prepregnant BMI

The new IOM guidelines for gestational weight gain(GWG) are specific for prepregnant BMI(ppg‐BMI) categories. Invariably ppg‐BMI is estimated at any trimesters of pregnancy by self‐reported height(ht) and weight(wt) data collected during the first prenatal visit. We aimed to identify determinants of valid self‐reported ppg‐ht and reliable ppg‐wt in pregnant women. Included in our study are 246 pregnant women in all three trimesters of pregnancy, aged 18–43yrs, and in NHANES 2005–06 with demographic, reproductive health, weight history and 2‐d dietary interview questionnaire data. SAS 9.1 was used for all statistical analyses applying for sample weights to account for the complex sampling design. We found that 69% of the subjects reported accurate ht with <0.5” difference from the measured, 21% overreported, and 10% underreported; inaccurate ht recalls(>0.5” differences) were prevalent among those born in Mexico or elsewhere(56%), less educated, overweight or obese women with no differences by age. In normal BMI group, the self‐reported ht predicted the measured ht in both pregnant(β=0.93102) and non‐pregnant(β=0.90453) groups and had a lower prevalence of excessive rate GWG(p<0.05). Our findings suggest opportunities associated with implementing and monitoring the new GWG guidelines that are based on ppg‐BMI, at the health‐professional and researcher levels. Grant Funding Source : None