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Validity of Birth Certificate‐Derived Maternal Weight Data
Author(s) -
Bodnar Lisa M.,
Abrams Barbara,
Bertolet Marnie,
Gernand Alison D.,
Parisi Sara M.,
Himes Katherine P.,
Lash Timothy L.
Publication year - 2014
Publication title -
paediatric and perinatal epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.667
H-Index - 88
eISSN - 1365-3016
pISSN - 0269-5022
DOI - 10.1111/ppe.12120
Subject(s) - medicine , birth certificate , underweight , overweight , body mass index , birth weight , percentile , gestational age , medical record , obstetrics , obesity , demography , ethnic group , pregnancy , population , environmental health , statistics , mathematics , sociology , biology , anthropology , genetics
Background Studies using vital records‐based maternal weight data have become more common, but the validity of these data is uncertain. Methods We evaluated the accuracy of prepregnancy body mass index ( BMI ) and gestational weight gain ( GWG ) reported on birth certificates using medical record data in 1204 births at a teaching hospital in P ennsylvania from 2003 to 2010. Deliveries at this hospital were representative of births statewide with respect to BMI , GWG , race/ethnicity, and preterm birth. Forty‐eight strata were created by simultaneous stratification on prepregnancy BMI (underweight, normal weight/overweight, obese class 1, obese classes 2 and 3), GWG (<20th, 20–80th, >80th percentile), race/ethnicity (non‐ H ispanic white, non‐ H ispanic black), and gestational age (term, preterm). Results The agreement of birth certificate‐derived prepregnancy BMI category with medical record BMI category was highest in the normal weight/overweight and obese class 2 and 3 groups. Agreement varied from 52% to 100% across racial/ethnic and gestational age strata. GWG category from the birth registry agreed with medical records for 41–83% of deliveries, and agreement tended to be the poorest for very low and very high GWG . The misclassification of GWG was driven by errors in reported prepregnancy weight rather than maternal weight at delivery, and its magnitude depended on prepregnancy BMI category and gestational age at delivery. Conclusions Maternal weight data, particularly at the extremes, are poorly reported on birth certificates. Investigators should devote resources to well‐designed validation studies, the results of which can be used to adjust for measurement errors by bias analysis.