US schools increasingly report body mass index (BMI) to students and their parents in annual fitness "report cards." We obtained 3,592,026 BMI reports for New York City public school students for [2007][2008][2009][2010][2011][2012]. We focus on female students whose BMI puts them close to their age-specific cutoff for categorization as overweight. Overweight students are notified that their BMI "falls outside a healthy weight" and they should review their BMI with a health care provider. Using a regression discontinuity design, we compare those classified as overweight but near to the overweight cutoff to those whose BMI narrowly earned them a "healthy" BMI grouping. We find that overweight categorization generates small impacts on girls' subsequent BMI and weight. Whereas presumably an intent of BMI report cards was to slow BMI growth among heavier students, BMIs and weights did not decline relative to healthy peers when assessed the following academic year. Our results speak to the discrete categorization as overweight for girls with BMIs near the overweight cutoff, not to the overall effect of BMI reporting in New York City.besity often emerges early in childhood. Among 7,738 US children, eighth graders were four times as likely to be obese if they were overweight in kindergarten (1). Parents can be surprisingly uninformed about overweight and obesity status of their children. Sixty-one percent of parents in San Diego correctly identified whether their child was overweight (2). "Obliviobesity" among US parents may be growing over time (3,4). On the other hand, US school districts and states have begun distributing annual fitness and body mass index (BMI) "report cards" to students and parents. Such personalized informational interventions have appeal in economics because they can be relatively inexpensive, particularly compared with traditional programs that include the delivery of costly health services. As individual dietary and exercise habits are being established during childhood, it has been argued that obesity surveillance, reporting, and prevention interventions should likewise begin early.Opponents of BMI reporting argue that informing children that they are "fat" can be stigmatizing, hurt their self-esteem, and even encourage bullying. Such unintended reactions may prompt a cascade of behavioral responses that do not improve health (5). Additionally, BMI (weight divided by height squared) is routinely criticized as a metric of fitness. Whether BMI report cards are an effective tool for helping to reduce obesity is not obvious a priori. Large-scale empirical analyses are now feasible thanks to expanded collection of BMI data, data generated for the administrative purpose of issuing BMI report cards.Fitnessgrams were adopted by New York City's public schools in 2007-2008, reporting each student's BMI alongside categorical BMI designations. Specifically, each student's BMI is classified and reported to be "underweight," "healthy," "overweight," or "obese." Categorizations are assigned using the studen...

Any opinions expressed in this paper are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but IZA takes no institutional policy positions. The IZA research network is committed to the IZA Guiding Principles of Research Integrity. The IZA Institute of Labor Economics is an independent economic research institute that conducts research in labor economics and offers evidence-based policy advice on labor market issues. Supported by the Deutsche Post Foundation, IZA runs the world's largest network of economists, whose research aims to provide answers to the global labor market challenges of our time. Our key objective is to build bridges between academic research, policymakers and society. IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author.

Any opinions expressed in this paper are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but IZA takes no institutional policy positions. The IZA research network is committed to the IZA Guiding Principles of Research Integrity. The IZA Institute of Labor Economics is an independent economic research institute that conducts research in labor economics and offers evidence-based policy advice on labor market issues. Supported by the Deutsche Post Foundation, IZA runs the world's largest network of economists, whose research aims to provide answers to the global labor market challenges of our time. Our key objective is to build bridges between academic research, policymakers and society. IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author.

Objectives The current study aimed to investigate whether pregnancy outcomes are affected by maternal rhesus (Rh) status by comparing the primigravida pregnancy outcomes of Rh-negative women with those of Rh-positive women. Methods The study data were collected from the Korea National Health Insurance Claims Database and the National Health Screening Program for Infants and Children. In total, 1,664,882 primigravida women who gave birth between January 1, 2007 and December 31, 2014, were enrolled in this study. As the risk and severity of sensitization response increases with each subsequent pregnancy, only primigravida women were enrolled. The patients were divided into 2 groups according to Rh status, and the pregnancy outcomes were compared. Results In total, 1,661,320 women in the Rh-positive group and 3,290 in the Rh-negative group were assessed. With regard to adverse pregnancy outcomes, there was no statistically significant difference between the 2 groups in terms of the prevalence of preeclampsia, postpartum hemorrhage, abruptio placenta, placenta previa, and uterine artery embolization. A univariate analysis revealed that none of the adverse pregnancy outcomes were significantly correlated to Rh status (preeclampsia: odds ratio [OR], 1.00, 95% confidence interval [CI], 0.81–1.23; postpartum hemorrhage: OR, 1.10, 95% CI, 0.98–1.24; abruptio placenta: OR, 0.80, 95% CI, 0.46–1.37; and placenta previa: OR, 1.08, 95% CI, 0.78–1.42). The adjusted ORs of postpartum hemorrhage and preterm birth did not significantly differ. Conclusion Maternal Rh status is not associated with adverse outcomes in primigravida women.

We use temperature variation within narrowly defined geographic and demographic cells to show that exposure to extreme temperature increases the risk of maternal hospitalization during pregnancy. This effect is driven by emergency hospitalizations for various pregnancy complications, suggesting that it represents a deterioration in underlying maternal health rather than a change in women's ability to access health care. The effect is larger for black women than for women of other races, suggesting that without significant adaptation, projected increases in extreme temperatures over the next century may further exacerbate racial disparities in maternal health.