Poster Session II Hypertension, Diabetes, Prematurity, Physiology www.AJOG.org

likely to receive postpartum glucose testing. Whereas, patients withpharmacotherapy for GDM were more likely to be screened.CONCLUSION: In this study, 55.1% of the patient with GDM failed tocomplete postpartum glucose testing. Considering the relative highprevalence of diabetes (18.4%) persisting in postpartum period inGDM in our study population, it seems urgently necessary toemphasize to patients with factors affecting noncompliance totesting about importance of postpartum glucose testing. Further-more, to encourage postpartum glucose testing in patients who hadbeen referred from private other clinics, collaborative strategy toalert the patient for follow up testing should be implemented.

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Maternal obesity and perinatal outcomes: does thedefinition of obesity matter?Jonathan Snowden1, Blair Darney1, Yvonne Cheng2,Nicole Marshall1, Elliott Main3, William Gilbert4, Judith Chung5,Aaron Caughey11Oregon Health & Science University, Portland, OR, 2University of California,San Francisco, San Francisco, CA, 3California Pacific Medical Center, SanFrancisco, CA, 4Sutter Health, Sacramento, CA, 5University of California,Irvine, Irvine, CA

OBJECTIVE: Maternal obesity strongly predicts adverse perinataloutcomes, but body mass index (BMI) data are frequently unavai-lable in large databases. Prior research has used binary weight cutoffsas a proxy for obesity. We compared a common weight-based defi-nition of obesity to the BMI definition, to assess misclassificationand impact on effect estimates.STUDY DESIGN: This was a retrospective cohort study of all non-anomalous, singleton California deliveries in 2007, analyzing linkedbirth certificate and patient discharge data. We employed a commonbinary weight-based obesity definition (prepregnancy weight � 200lbs) and the BMI-based obesity definition (BMI � 30 kg/m2). Weassessed misclassification of maternal obesity using the weight-baseddefinition. We calculated frequency of adverse perinatal outcomesbetween obese and non-obese women and conducted multivariablelogistic regression to examine the impact of using a weight-baseddefinition of obesity.RESULTS: A smaller proportion of women were classified as obeseusing the weight-based definition compared with the BMI-baseddefinition (8.6% versus 18.8%, P<0.001). A majority of obesewomen (55.3%) were misclassified as non-obese using the simplerdefinition. This misclassification was most frequent in women ofshort stature and Hispanic and Asian-American women. The weight-based definition tended to exaggerate the prevalence of perinataloutcomes in obese women compared with the BMI definition (e.g.,gestational hypertension, 13.6% versus 10.9%), strengthening thecorresponding effect estimates (weight-based aOR: 2.93, 95% CI:2.83 - 3.03 vs BMI-based aOR: 2.63, 95% CI: 2.55 - 2.70). This trendwas attenuated for outcomes where short stature is a risk factor (e.g.,low birthweight).CONCLUSION: Using a binary weight-based definition misclassifies amajority of obese women. This misclassification biases estimates ofperinatal outcomes among obese women. The direction andmagnitude of the bias depends on the perinatal outcome beingstudied.

S168 American Journal of Obstetrics & Gynecology Supplement to JANUARY

Misclassification of obesity and prevalence ofperinatal outcomes using a weight-based and aBMI-based definition of obesity

323 Gestational diabetes, obesity, and self perceived risk of

type 2 diabetesRabia Siddik-Ahmad1, Matthew Garabedian1, Francesca Ianovich1,Nisha Jadhaw1, Kristine Lain21Santa Clara Valley Medical Center, Department of Obstetrics andGynecology, San Jose, CA, 2Norton Healthcare, Kosair Children’s HospitalMaternal Fetal Medicine, Louisville, KY

OBJECTIVE: To evaluate self-perceived risk of Type 2 Diabetes(T2DM) in patients with gestational diabetes (GDM). We hypoth-esized that women with GDM would perceive higher risk and bemore willing to make lifestyle changes when compared to non-diabetic controls. As obesity is also a risk factor for T2DM, we alsoexamined patient perception of risk related to obesity.STUDY DESIGN: This is a cross sectional study of postpartum womenat a tertiary care center from July 1, 2012 to May 31, 2013. Womenwithout pre-gestational diabetes and with a pre-pregnancy BMI �18.5 were eligible for inclusion. The primary outcome was self-perceived risk of T2DM. Secondary outcomes included willingnessto make lifestyle changes and perception that these changes couldmodify risk assessed using an externally validated questionnaire.Secondary-analysis was performed to assess these outcomes in obeseand non-obese, non-diabetic subjects.RESULTS: 195 patients were enrolled. Patients with GDM were morelikely to report high perception of T2DM risk in the next 10 yearsthan patients without GDM (75.0% v. 15.5%, p<0.01). However,GDM patients were not more willing to make healthier lifestylechanges (82.1% v. 76.9%, p¼0.54). Obese patients without diabeteswere no more likely to report high risk of T2DM than their non-obese non-diabetic cohort (14.9% v. 14.8%, p¼0.98) and were notmore willing to make healthier lifestyle changes (80.8% v. 70.6%,p¼0.18). Both GDM patients as well as non-diabetic obese patientsdemonstrated understanding that a history of GDM is a risk factorfor T2DM, but showed inconsistent knowledge regarding modifiableand non-modifiable risk factors (Table).CONCLUSION: GDM patients perceive themselves at high risk ofdeveloping T2DM, but obese patients do not. Neither group wasmore willing to implement lifestyle changes for risk modificationcompared to controls. These findings identify a need for targetededucation regarding potential for risk modification by healthierlifestyle choices.

2014