Professional Education

  • Doctor of Philosophy, Johns Hopkins University (2016)
  • Master of Health and Science, Johns Hopkins University (2011)
  • Bachelor of Arts, University of Southern California (2007)

Stanford Advisors

All Publications

  • Data-Driven Queries between Medications and Spontaneous Preterm Birth among 2.5 Million Pregnancies: Association with Genital Herpes and Antiviral Drugs. Maric, I., Borisenko, E., Winn, V. D., Weber, K. A., Wong, R. J., Aziz, N., Blumenfeld, Y. J., El-Sayed, Y. Y., Stevenson, D. K., Shaw, G. M. SAGE PUBLICATIONS INC. 2019: 389A
  • A machine learning approach to investigate potential risk factors for gastroschisis in California. Birth defects research Weber, K. A., Yang, W., Carmichael, S. L., Padula, A. M., Shaw, G. M. 2018


    BACKGROUND: To generate new leads about risk factors for gastroschisis, a birth defect that has been increasing in prevalence over time, we performed an untargeted data mining statistical approach.METHODS: Using data exclusively from the California Center of the National Birth Defects Prevention Study, we compared 286 cases of gastroschisis and 1,263 non-malformed, live-born controls. All infants had delivery dates between October 1997 and December 2011 and were stratified by maternal age at birth (<20 and ≥ 20years). Cases and controls were compared by maternal responses to 183 questions (219 variables) using random forest, a data mining procedure. Variables deemed important by random forest were included in logistic regression models to estimate odds ratios and 95% confidence intervals.RESULTS: Among women younger than 20, of variables deemed important, there were higher odds observed for higher consumption of chocolate, low intake of iron, acetaminophen use, and urinary tract infections during the beginning of pregnancy. After adjustment, the higher odds remained for low iron intake and a urinary tract infection in the first month of pregnancy. Among women aged 20 or older, of variables deemed important, higher odds were observed for US-born women of Hispanic ethnicity and for parental substance abuse. There were lower odds observed for obese women, women who ate any cereal the month before pregnancy, and those with higher parity.CONCLUSIONS: We did not discover many previously unreported associations, despite our novel approach to generate new hypotheses. However, our results do add evidence to some previously proposed risk factors.

    View details for PubMedID 30588769

  • An application of data mining to identify potential risk factors for anophthalmia and microphthalmia. Paediatric and perinatal epidemiology Weber, K. A., Yang, W., Carmichael, S. L., Lupo, P. J., Dukhovny, S., Yazdy, M. M., Lin, A. E., Van Bennekom, C. M., Mitchell, A. A., Shaw, G. M., National Birth Defects Prevention Study 2018


    BACKGROUND: We examined a large number of variables to generate new hypotheses regarding a wider range of risk factors for anophthalmia/microphthalmia using data mining.METHODS: Data were from the National Birth Defects Prevention Study, a multicentre, case-control study from 10 centres in the United States. There were 134 cases of "isolated" and 87 "nonisolated" (with other major birth defects) of anophthalmia/microphthalmia and 11052 nonmalformed controls with delivery dates October 1997-December 2011. Using random forest, a data mining procedure, we compared the two case types with controls for 201 variables. Variables considered important ranked by random forest were included in a multivariable logistic regression model to estimate odds ratios and 95% confidence intervals.RESULTS: Predictors for isolated cases included paternal race/ethnicity, maternal intake of certain nutrients and foods, and childhood health problems in relatives. Using regression, inverse associations were observed with greater maternal education and with increasing intake of folate and potatoes. Odds were slightly higher with greater paternal education, for increased intake of carbohydrates and beans, and if relatives had a childhood health problem. For nonisolated cases, predictors included paternal race/ethnicity, maternal intake of certain nutrients, and smoking in the home the month before conception. Odds were higher for Hispanic fathers and smoking in the home and NSAID use the month before conception.CONCLUSIONS: Results appear to support previously hypothesised risk factors, socio-economic status, NSAID use, and inadequate folate intake, and potentially provide new areas such as passive smoking pre-pregnancy, and paternal education and ethnicity, to explore for further understanding of anophthalmia/microphthalmia.

    View details for PubMedID 30300919

  • Epidemiology of anophthalmia and microphthalmia: Prevalence and patterns in Texas, 1999-2009 AMERICAN JOURNAL OF MEDICAL GENETICS PART A Chambers, T. M., Agopian, A. J., Lewis, R. A., Langlois, P. H., Danysh, H. E., Weber, K. A., Shaw, G. M., Mitchell, L. E., Lupo, P. J. 2018; 176 (9): 1810–18


    Anophthalmia and microphthalmia are a set of rare, yet severe, birth defects considered to be part of a spectrum of developmental ocular malformations ranging from smaller than average to completely absent eyes. Despite their clinical significance, little is known about the etiologies of these conditions. The goal of this study was to expand our understanding of the epidemiology of anophthalmia and microphthalmia. Data for this population-based assessment were obtained from the Texas Birth Defects Registry (TBDR) and Center for Health Statistics for the period 1999-2009. Descriptive analyses and estimates of birth prevalence and prevalence ratios (PR) were determined for this defect. There were 1,262 definite anophthalmia and microphthalmia patients identified in the TBDR, with an overall combined prevalence of 3.0 per 10,000 live births. More than half (55.7%) of the patients had at least one chromosome abnormality or syndrome. In addition, 92.4% of nonsyndromic patients (i.e., have no recorded chromosome abnormalities or syndromes) had at least one additional birth defect. After adjustment for multiple factors, the prevalence of nonsyndromic anophthalmia and microphthalmia was higher among mothers who had ≥2 previous fetal deaths (PR = 1.43, 95% confidence interval [CI]: 1.03-1.97) and among mothers with any reported diabetes (PR = 2.08, 95% CI: 1.49-2.90). Our results confirm that children with anophthalmia and microphthalmia frequently have genetic syndromes or are born with other major birth defects. Our findings add to the limited body of literature on anophthalmia and microphthalmia as well as help define subgroups of women who are more likely to have children with this malformation.

    View details for PubMedID 30070760

  • Residential agricultural pesticide exposures and risks of preeclampsia. Environmental research Shaw, G. M., Yang, W., Roberts, E. M., Aghaeepour, N., Mayo, J. A., Weber, K. A., Maric, I., Carmichael, S. L., Winn, V. D., Stevenson, D. K., English, P. B. 2018; 164: 546–55


    We investigated risks of preeclampsia phenotypes from potential residential pesticide exposures, including 543 individual chemicals and 69 physicochemical groupings that were applied in the San Joaquin Valley of California during the study period, 1998-2011. The study population was derived from birth certificate data linked with Office of Statewide Health Planning and Development maternal and infant hospital discharge data. The following numbers of women with preeclampsia phenotypes were identified: 1045 with superimposed (pre-existing hypertension with preeclampsia) preeclampsia (265 with gestational weeks 20-31 and 780 with gestational weeks 32-36); 3471 with severe preeclampsia (824 with gestational weeks 20-31 and 2647 with gestational weeks 32-36); and 2780 with mild preeclampsia (207 with gestational weeks 20-31 and 2573 with gestational weeks 32-36). The reference population for these groups was 197,461 women who did not have diabetes (gestational or pre-existing), did not have any hypertensive disorder, and who delivered at 37 weeks or later. The frequency of any exposure was lower or about the same in each preeclampsia case group (further delineated by gestational age), and month time period, relative to the frequency in reference population controls. Nearly all odds ratios were below 1.0 for these any vs no exposure comparisons. This study showed a general lack of increased risks between a range of agriculture pesticide exposures near women's residences and various preeclampsia phenotypes.

    View details for PubMedID 29614386

  • Nutrient intake in women before conception and risks of anophthalmia and microphthalmia in their offspring. Birth defects research Weber, K. A., Yang, W., Carmichael, S. L., Shaw, G. M., National Birth Defects Prevention Study 2018; 110 (10): 863–70


    BACKGROUND: We previously explored associations between nutrients including folate and other macro and micronutrients and risks of anophthalmia or microphthalmia in the National Birth Defects Prevention Study. In the current study, we expand those previous results with larger sample sizes and conduct analyses with an additional diet quality index using more recent data.METHODS: The National Birth Defects Prevention Study is a population-based, multicenter case-control study of over 30 major birth defects, with estimated due dates from October 1997 to December 2011. Cases were 224 infants diagnosed with anophthalmia or microphthalmia. Controls were 11,109 live-born, nonmalformed infants randomly selected by each study center. Mothers completed a standardized, computer-assisted telephone interview between 6 weeks and 24 months after delivery. Mothers responded to a shortened food frequency questionnaire, assessing their nutrient intake for the year before pregnancy, and questions about periconceptional (2 months before to 2 months after conception) vitamin supplement use. Nutrient intake quartiles were based on the intake among controls.RESULTS: Among vitamin supplement users, odds of anophthalmia/microphthalmia were decreased for women with intake levels in the highest quartile of folate (0.56, 95% confidence interval [CI] 0.32-0.98), magnesium (0.42, 95% CI 0.22-0.82), and vitamin E (0.50, 95% CI 0.29-0.89). Among women not reporting vitamin supplement use, the odds were significantly increased for beta-carotene (2.5, 95% CI 1.10-5.68) and decreased for retinol (0.37, 95% CI 0.19-0.73).CONCLUSIONS: In this expanded analysis, we observed associations for a few nutrients, specifically forms of vitamin A. However, the heterogeneity of results by form and vitamin use necessitates further inquiry.

    View details for PubMedID 29504274

  • Occurrence of Selected Structural Birth Defects Among Women With Preeclampsia and Other Hypertensive Disorders AMERICAN JOURNAL OF EPIDEMIOLOGY Weber, K. A., Mayo, J. A., Carmichael, S. L., Stevenson, D. K., Winn, V. D., Shaw, G. M. 2018; 187 (4): 668–76


    To explore a potential association between preeclampsia and selected birth defects, we examined the prevalence of certain birth defects among women with hypertensive disorders including preeclampsia. We analyzed data from 2,499,536 singleton live births in California from 2007 to 2011, including maternal and infant demographics from birth certificates as well as clinical details from delivery hospitalization records. We examined defect groups that were recognizable at birth (e.g., spina bifida and cleft lip). Hypertensive disorders included preexisting hypertension, gestational hypertension, mild preeclampsia, severe preeclampsia/eclampsia, and preeclampsia superimposed on preexisting hypertension. Relative risk values with 95% confidence intervals for each birth defect were calculated by hypertensive group, as well as independent and joint associations of hypertensive and diabetic disorders. Risks of each type of birth defect were higher among offspring of women with hypertensive disorders compared with those without. The risks of birth defects among offspring of women with only a hypertensive disorder were significantly higher than that among women with neither hypertensive nor diabetic disorders (relative risks ranged from 1.37 to 2.77). Risks of birth defects were highest among those born to women with both hypertensive and diabetic disorders compared with those with neither (relative risks ranged from 1.80 to 6.22). These findings support the existence of an association between preeclampsia and certain birth defects and suggest that diabetes may be a contributing factor.

    View details for PubMedID 29020134