Hyagriv N Simhan

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (167)651.47 Total impact

  • Jacob Larkin, Hyagriv Simhan
    American Journal of Obstetrics and Gynecology 01/2013; 208(1):S16. · 3.97 Impact Factor
  • American Journal of Obstetrics and Gynecology 01/2013; 208(1):S44. · 3.97 Impact Factor
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    ABSTRACT: Background Although the etiology of preeclampsia is not well understood, it has been suggested that excessive systemic inflammation may lead to oxidative stress, promoting the endothelial dysfunction characteristic of preeclampsia. Few prospective studies have examined the role of infection, an immune system stimulator, as a risk factor for preeclampsia.Methods We conducted a longitudinal study of the relationships between Chlamydia trachomatis (CT), Chlamydophila pneumoniae (CP), cytomegalovirus (CMV), herpes simplex virus (HSV) and preeclampsia among 509 preeclamptic cases and 336 normotensive controls nested within the Danish National Birth Cohort study. Antibodies were analyzed at a first prenatal visit (mean 17.0 weeks) and at a late second/third trimester study visit. Prenatal infections were identified as IgG/IgM seroconversion or a fourfold rise in IgG antibody titers. Multiple regression models were adjusted for maternal age, BMI, smoking status, and time between blood draws.ResultsCT infection was associated with preeclampsia (ORadj 1.6, 95% CI 0.7, 3.6), severe preeclampsia (ORadj 1.8, 95% CI 0.6, 5.3), and preeclampsia resulting in preterm birth (ORadj 1.7, 95% CI 0.6–4.9) or birth of a small for gestational age infant (ORadj 2.1, 95% CI 0.6, 7.5), although CT infection was uncommon (n = 33, 4.0%) and associations were not statistically significant. CP, CMV, and HSV infection were not associated with preeclampsia.Conclusions Women with serological evidence of prenatal CT infection were more likely to develop preeclampsia, although infection was infrequent and confidence intervals were wide. Studies in populations at higher risk for STIs are needed to corroborate this association.
    Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health. 01/2013; 3(1):28–33.
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    ABSTRACT: OBJECTIVE: In adults one of the major determinants of leukocyte telomere length (LTL), a predictor of age-related diseases and mortality, is cumulative psychosocial stress exposure. More recently we reported that exposure to maternal psychosocial stress during intrauterine life is associated with LTL in young adulthood. The objective of the present study was to determine how early in life this effect of stress on LTL is apparent by quantifying the association of maternal psychosocial stress during pregnancy with newborn TL. STUDY DESIGN: In a prospective study of N=27 mother-newborn dyads maternal pregnancy-specific stress was assessed in early gestation and cord blood PBMCs were subsequently collected and analyzed for LTL measurement. RESULTS: After accounting for the effects of potential determinants of newborn LTL (gestational age at birth, weight, sex and exposure to antepartum obstetric complications), there was a significant, independent, linear effect of pregnancy-specific stress on newborn LTL that accounted for 25% of the variance in adjusted LTL (β=-0.099; p=0.04). CONCLUSIONS: Our finding provides the first preliminary evidence in humans that maternal psychological stress during pregnancy may exert a "programming" effect on the developing telomere biology system that is already apparent at birth, as reflected by the setting of newborn leukocyte telomere length.
    American journal of obstetrics and gynecology 11/2012; · 3.97 Impact Factor
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    ABSTRACT: Background:To identify genetic variants contributing to preterm birth using a linkage candidate gene approach.Methods:We studied 99 single nucleotide polymorphisms for 33 genes in 257 families with preterm births segregating. Nonparametric and parametric analyses were used. Premature infants and mothers of premature infants were defined as affected cases in independent analyses.Results:Analyses with the infant as the case identified two genes with evidence of linkage: CRHR1 (p=0.0012) and CYP2E1 (p=0.0011). Analyses with the mother as the case identified four genes with evidence of linkage: ENPP1 (p=0.003), IGFBP3 (p=0.006), DHCR7 (p=0.009), and TRAF2 (p=0.01). DNA sequence analysis of the coding exons and splice sites for CRHR1 and TRAF2 identified no new likely etiologic variants.Conclusion:These findings suggest the involvement of six genes acting through the infant and/or the mother in the etiology of preterm birth.Pediatric Research (2012); doi:10.1038/pr.2012.166.
    Pediatric Research 11/2012; · 2.84 Impact Factor
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    ABSTRACT: Context:Inconsistent associations between maternal vitamin D status and fetal size have been published in small studies.Objective:Our objective was to examine the association between maternal 25-hydroxyvitamin D [25(OH)D] levels and measures of newborn and placental weight.Design and Setting:We measured maternal 25(OH)D in mothers from the Collaborative Perinatal Project, an observational cohort conducted in 12 U.S. medical centers from 1959 to 1965.Participants:Women delivering singleton, term, live births with 25(OH)D measured at a gestation of 26 wk or less (n = 2146).Main Outcome Measures:Birth weight, ponderal index, placental weight, the placental to fetal weight ratio, and small for gestational age were measured. Hypotheses were formulated after data collection.Results:After confounder adjustment, mothers with 25(OH)D of 37.5 nmol/liter or greater gave birth to newborns with 46 g [95% confidence interval (CI), 9-82 g] higher birth weights and 0.13 cm (0.01-0.25 cm) larger head circumferences compared with mothers with less than 37.5 nmol/liter. Birth weight and head circumference rose with increasing 25(OH)D up to 37.5 nmol/liter and then leveled off (P < 0.05). No association was observed between 25(OH)D and ponderal index, placental weight, or the placental to fetal weight ratio. Maternal 25(OH)D of 37.5 nmol/liter or greater vs. less than 37.5 nmol/liter in the first trimester was associated with half the risk of small for gestational age (adjusted odds ratio 0.5; 95% CI 0.3-0.9), but no second-trimester association was observed.Conclusions:Maternal vitamin D status is independently associated with markers of physiological and pathological growth in term infants. Adequately powered randomized controlled trials are needed to test whether maternal vitamin D supplementation may improve fetal growth.
    The Journal of Clinical Endocrinology and Metabolism 11/2012; · 6.31 Impact Factor
  • Amber Naresh, Hyagriv Simhan
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    ABSTRACT: Preterm premature rupture of membranes (PPROM) and preterm birth are strongly linked to intrauterine inflammation. Bacterial infection is often not identified as the cause. The objective was to examine the amniotic fluid of women with PPROM for viral genomic content, and to correlate with the presence of bacterial infection and markers of intrauterine inflammation. A case series of 13 women with PPROM is presented. Amniocentesis was performed in each of these women. DNA/RNA isolated from amniotic fluid was tested using polymerase chain reaction (PCR) for the presence of herpes simplex virus (HSV)-1 and -2, adenovirus, adeno-associated virus-2 (AAV-2), cytomegalovirus (CMV), parvovirus B19, human papilloma viruses (HPV), and enteroviruses. Maternal and neonatal hospital course and laboratory information, including results of amniotic fluid inflammatory marker testing and bacterial culture, were determined from the medical record. All amniotic fluid samples were negative for HSV-1 and HSV-2, adenovirus, AAV-2, CMV, parvovirus B19, HPV, and enteroviruses. Six of the 13 fluid samples (46%) had positive bacterial cultures, including culture for atypical organisms. In a small series of women, viral infection as assessed by the presence of viral genomic content in the amniotic fluid was not associated with PPROM.
    Journal of Reproductive Immunology 09/2012; · 2.37 Impact Factor
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    ABSTRACT: Given the unique role of the corticotrophin-releasing hormone (CRH) system in human fetal development, the aim of our study was to estimate the association of birth weight with DNA sequence variation in three maternal genes involved in regulating CRH production, bioavailability and action: CRH, CRH-Binding Protein (CRH-BP), and CRH type 1 receptor (CRH-R1), respectively, in three racial groups (African-Americans, Hispanics, and non-Hispanic Whites). Our study was carried out on a population-based sample of 575 mother-child dyads. We resequenced the three genes in mouse-human hybrid somatic cell lines and selected SNPs for genotyping. A significant association was observed in each race between birth weight and maternal CRH-BP SNP genotypes. Estimates of linkage disequilibrium and haplotypes established three common haplotypes marked by the rs1053989 SNP in all three races. This SNP predicted significant birth weight variation after adjustment for gestational age, maternal BMI, parity, and smoking. African American and Hispanic mothers carrying the A allele had infants whose birth weight was on average 254 and 302 grams, respectively, less than infants having C/C mothers. Non-Hispanic White mothers homozygous for the A allele had infants who were on average 148 grams less than those infants having A/C and C/C mothers. The magnitudes of the estimates of the birth weight effects are comparable to the combined effects of multiple SNPs reported in a recent meta-analysis of 6 GWAS studies and is quantitatively larger than that associated with maternal cigarette smoking. This effect was persistent across subpopulations that vary with respect to ancestry and environment.
    PLoS ONE 09/2012; 7(9):e43931. · 3.53 Impact Factor
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    ABSTRACT: OBJECTIVE: We sought to evaluate in women with twin gestation the relationship between 17-hydroxyprogesterone caproate (17-OHPC) concentration and gestational age at delivery and select biomarkers of potential pathways of drug action. STUDY DESIGN: Blood was obtained between 24-28 weeks (epoch 1) and 32-35 weeks (epoch 2) in 217 women with twin gestation receiving 17-OHPC or placebo. Gestational age at delivery and concentrations of 17-OHPC, 17-hydroxyprogesterone, progesterone, C-reactive protein (CRP), and corticotrophin-releasing hormone were assessed. RESULTS: Women with higher concentrations of 17-OHPC delivered at earlier gestational ages than women with lower concentrations (P < .001). Women receiving 17-OHPC demonstrated significantly higher (P = .005) concentrations of CRP in epoch 1 than women receiving placebo but CRP values were similar in epoch 2 in both groups. A highly significant (P < .0001) positive relationship was observed between 17-OHPC concentration and progesterone and 17-hydroxyprogesterone concentrations at both epochs. Corticotropin-releasing hormone concentrations did not differ by treatment group. CONCLUSION: 17-OHPC may adversely impact gestational age at delivery in women with twin gestation.
    American journal of obstetrics and gynecology 08/2012; · 3.97 Impact Factor
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    ABSTRACT: Very preterm birth (VPTB) is a leading cause of infant mortality, morbidity and racial disparity in the US. The underlying causes of VPTB are multiple and poorly understood. The California Very Preterm Birth Study was conducted to discover maternal and infant genetic and environmental factors associated with VPTB. This paper describes the study design, population, data and specimen collection, laboratory methods and characteristics of the study population. Using a large, population-based cohort created through record linkage of livebirths delivered from 2000 to 2007 in five counties of southern California, and existing data and banked specimens from statewide prenatal and newborn screening, 1100 VPTB cases and 796 control mother-infant pairs were selected for study (385/200 White, 385/253 Hispanic and 330/343 Black cases/controls, respectively). Medical record abstraction of cases was conducted at over 50 hospitals to identify spontaneous VPTB, improve accuracy of gestational age, obtain relevant clinical data and exclude cases that did not meet eligibility criteria. VPTB was defined as birth at <32 weeks in Whites and Hispanics and <34 weeks in Blacks. Approximately 55% of all VPTBs were spontaneous and 45% had medical indications or other exclusions. Of the spontaneous VPTBs, approximately 41% were reported to have chorioamnionitis. While the current focus of the California Very Preterm Birth Study is to assess the role of candidate genetic markers on spontaneous VPTB, its design enables the pursuit of other research opportunities to identify social, clinical and biological determinants of different types of VPTB with the ultimate aim of reducing infant mortality, morbidity and racial disparities in these health outcomes in the US and elsewhere.
    Paediatric and Perinatal Epidemiology 05/2012; 26(3):250-63. · 2.16 Impact Factor
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    ABSTRACT: Three large randomized controlled trials investigating the efficacy of universal cervical length screening and treatment with vaginal progesterone or cervical cerclage to prevent preterm delivery have been published over the past several years. None of these trials demonstrate proven efficacy for universal cervical length screening and cerclage placement in women with short cervical length. However, universal cervical length screening and treatment with daily vaginal progesterone in women with short cervical length reduces the risk of preterm birth, but large numbers of women must be screened to prevent a relatively small number of preterm deliveries. Issues that should be considered while implementing universal cervical length screening include: (1) standards of quality and reproducibility for transvaginal ultrasound cervical length ascertainment; (2) implications of screening on the application of therapeutic strategies to populations not known to benefit (so-called "indication creep"); and (3) willingness of obstetricians to prescribe vaginal progesterone formulations that are not approved by the US Food and Drug Administration for preterm birth prevention. Optimal strategies to employ cervical ultrasound and progesterone treatment might be revealed by additional studies investigating cervical length cutoffs, frequency of screening, selective screening in higher-risk groups, and the use of transabdominal cervical length screening as a surrogate for transvaginal cervical length screening.
    American journal of obstetrics and gynecology 04/2012; 207(2):101-6. · 3.97 Impact Factor
  • Steve N Caritis, Hyagriv Simhan
    The Lancet 04/2012; 379(9828):1769-70. · 39.21 Impact Factor
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    ABSTRACT: Conventional measures of gestational weight gain (GWG), such as average rate of weight gain, are likely to be correlated with gestational duration. Such a correlation could introduce bias to epidemiological studies of GWG and adverse perinatal outcomes because many perinatal outcomes are also correlated with gestational duration. This study aimed to quantify the extent to which currently used GWG measures may bias the apparent relationship between maternal weight gain and risk of preterm birth. For each woman in a provincial perinatal database registry (British Columbia, Canada, 2000-2009), a total GWG was simulated such that it was uncorrelated with risk of preterm birth. The simulation was based on serial antenatal GWG measurements from a sample of term pregnancies. Simulated GWGs were classified using three approaches: total weight gain (kg), average rate of weight gain (kg/week) or adequacy of GWG in relation to Institute of Medicine recommendations. Their association with preterm birth ≤32 weeks was explored using logistic regression. All measures of GWG induced an apparent association between GWG and preterm birth ≤32 weeks even when, by design, none existed. Odds ratios in the lowest fifths of each GWG measure compared with the middle fifths ranged from 4.4 [95% confidence interval (CI) 3.6, 5.4] (total weight gain) to 1.6 [95% CI 1.3, 2.0] (Institute of Medicine adequacy ratio). Conventional measures of GWG introduce serious bias to the study of maternal weight gain and preterm birth. A new measure of GWG that is uncorrelated with gestational duration is needed.
    Paediatric and Perinatal Epidemiology 03/2012; 26(2):109-16. · 2.16 Impact Factor
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    ABSTRACT: To estimate and compare the risk of morbid perinatal outcomes in pregnancies identified as small for gestational age (SGA) with customized compared with conventional standards of fetal growth. Ultrasound-derived estimates of fetal weight were used to generate a fetal growth trajectory (N=7,510). The gestational age at delivery and pathologic and physiologic variables from 5,072 pregnancies were used to calculate a customized threshold for SGA. In a separate analysis of 32,070 pregnancies, rates of morbid outcomes were compared in participants classified as SGA according to a population-based birth weight standard only (SGApop only), a customized standard only (SGAcust only), and both methods (SGAboth). Eight-hundred seventy-five (2.7%) participants were SGApop only, 1,970 (6.1%) participants were SGAboth, and 609 (1.9%) participants were SGAcust only. The odds ratios of neonatal death in SGApop only and SGAcust only pregnancies were 1.78 (95% confidence interval [CI] 0.2-13.1) and 54.6 (95% CI 29.0-102.8), respectively. Rates of prematurity in the SGApop only and SGAcust only cohorts were 4.8% and 64.5%, respectively. After adjustment for the effect of prematurity, odds ratios of neonatal death in the SGApop only and SGAcust only cohorts were 4.8 (95% CI 0.6-37.0) and 2.9 (95% CI 1.4-6.1), respectively. After adjustment for confounding stemming from premature delivery, there is little difference in the risk of adverse outcomes between SGAcust only and SGApop only participants. Adoption of customized fetal growth standards into clinical practice may not improve the ability to identify pregnancies with increased risk of perinatal morbidity.
    Obstetrics and Gynecology 01/2012; 119(1):21-7. · 4.37 Impact Factor
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    ABSTRACT: Serum fatty acid binding protein 4 (FABP4) is associated with components of the metabolic syndrome in nonpregnant individuals, including dyslipidemia and insulin resistance. Preeclampsia shares many features with the metabolic syndrome, but the relationship between early pregnancy serum FABP4 levels and the development of preeclampsia is unknown. The aim of the study was to test the hypothesis that FABP4 is elevated in women who develop preeclampsia before the onset of disease. This was a nested case-control study within a larger prospective cohort of healthy women with singleton gestations. Cases included 22 women who developed preeclampsia, and a random sample of 72 unmatched controls delivered without preeclampsia was identified. Maternal serum FABP4 was measured at less than 13 wk gestation and 24-28 wk gestation, which was before the onset of preeclampsia in all patients. The main outcome measure was preeclampsia (new-onset gestational hypertension and proteinuria for the first time after 20 wk gestation). Maternal serum FABP4 concentrations were higher in women who ultimately developed preeclampsia both at 8-13 wk (20.4±12.3 vs. 10.1±4.7 ng/ml; P<0.01) and at 24-28 wk (20.7±11.7 vs. 9.9±4.5 ng/ml; P<0.01). After controlling for first trimester body mass index, systolic blood pressure, and nulliparity, FABP4 was associated with the development of preeclampsia (adjusted odds ratio, 1.2; 95% confidence interval, 1.1-1.3; P<0.01). Maternal serum FABP4 levels are elevated before the clinical onset of preeclampsia, and this increase occurs independently of maternal body mass index.
    The Journal of Clinical Endocrinology and Metabolism 12/2011; 97(3):E349-56. · 6.31 Impact Factor
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    ABSTRACT: Decidual cells are central to innate immunity at the maternal/fetal interface. We sought to characterize the response of decidual cells to stimulation and then removal of lipopolysaccharide (LPS) using a whole genome approach. Decidual cells were isolated from term unlabored cesarean sections. Cells were stimulated with LPS and RNA isolated both pre-stimulation and 2 and 24 h post-stimulation. Media were changed and RNA extracted 48 h later. Gene expression was measured using Agilent 44K whole genome microarrays. Data were visualized and interpreted using Ingenuity Pathway Analysis (IPA) software and selected (n=5) target gene expression was verified with quantitative real-time PCR. Genes related to immune function were up-regulated at 2 and 24 h after LPS exposure and then generally returned to baseline or were at least substantially reduced after LPS removal. Pathway analysis also revealed that genes involved in lipid metabolism (specifically cholesterol and steroid biosynthesis), iron metabolism, and the plasminogen system were coordinately altered following exposure to LPS. Our novel, preliminary findings provide insight into possible mechanisms via which the host inflammatory response could contribute to preterm birth and warrant further investigation in preterm samples.
    Journal of Reproductive Immunology 12/2011; 93(1):17-27. · 2.37 Impact Factor
  • Leslie A Moroz, Hyagriv N Simhan
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    ABSTRACT: We hypothesized that change in cervical length (CL) on serial ultrasounds is associated with spontaneous preterm birth (SPTB) <36 weeks for women with a short cervix (CL <25 mm). This was a secondary analysis of a multicenter prospective observational study designed to study predictors of preterm birth. Women from the general obstetric population had serial CL ultrasounds between 20-33 weeks' gestation and were followed up until delivery. Two thousand six hundred ninety five women had sonographic CL measurements. Change in CL was associated with SPTB for women with CL <25 mm (odds ratio, 0.97; 95% confidence interval, 0.96-0.98). Among women with a short cervix, for every 1 mm of cervical shortening between ultrasounds, there was a 3% increase in odds of SPTB. The association between change in CL and SPTB remained significant after controlling for age, race, body mass index, tobacco use, and fetal fibronectin test status. Among women with a sonographically short cervix, the rate of change in CL is associated with SPTB, independent of fetal fibronectin test and other important risk factors for SPTB.
    American journal of obstetrics and gynecology 12/2011; 206(3):234.e1-5. · 3.97 Impact Factor
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    ABSTRACT: To determine if subjects experiencing acute vaginal bleeding in early pregnancy have increased plasma markers of thrombin generation compared to nonbleeding controls. Subjects with clinically apparent acute (within 24 h of sample collection) vaginal bleeding between 6 and 20 weeks estimated gestational age and without known thrombophilias were enrolled, along with nonbleeding controls, and underwent collection of maternal plasma. Concentrations of thrombin-antithrombin (TAT) and fragment 1 + 2 (F1 + 2) were determined by enzyme-linked immunosorbent assay. Differences between bleeding and nonbleeding subjects were assessed through linear regression with adjustment for gestational age. Twenty subjects with vaginal bleeding and 20 controls were included. Bleeding was significantly associated with increased concentrations of TAT (p = 0.007) and F1 + 2 (p = 0.044) when corrected for gestational age. Among bleeding subjects, there was no association between markers of thrombin generation and the subject's description of bleeding quantity, though higher concentrations were associated with a longer self-reported duration of bleeding. Clinically apparent vaginal bleeding in early pregnancy is associated with increased circulating maternal markers of thrombin generation. Thus, these maternal markers may have a future role in risk stratification.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 11/2011; 25(8):1479-82. · 1.36 Impact Factor
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    Devon M Ramaeker, Hyagriv N Simhan
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    ABSTRACT: We sought to evaluate the contributions of vaginal bleeding and cervical length to the risk of preterm birth. This was a secondary analysis of a cohort study designed to study predictors of preterm birth. The study included 2988 women with singleton gestations. Women underwent midtrimester transvaginal ultrasound assessment of cervical length and were queried regarding first- and second-trimester vaginal bleeding. There was a significant second-order relation between cervical length and preterm birth (P < .001, P = .005). Women with vaginal bleeding were at higher risk of preterm birth (odds ratio, 1.5; 95% confidence interval, 1.3-2.0). There was a significant interaction between cervical length and vaginal bleeding (P = .015). After accounting for cervical length and interaction, the adjusted odds ratio for vaginal bleeding and preterm birth was 4.8 (95% confidence interval, 1.89-12.4; P = .001). The magnitude of risk of preterm birth associated with sonographic cervical length depends on a woman's history of first- and second-trimester vaginal bleeding.
    American journal of obstetrics and gynecology 11/2011; 206(3):224.e1-4. · 3.97 Impact Factor
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    ABSTRACT: To examine associations between rs9883204 in ADCY5 and rs900400 near LEKR1 and CCNL1 with birth weight in a preterm population. Both markers were associated with birth weight in a term population in a recent genome-wide association study of Freathy et al. A meta-analysis of mother and infant samples was performed for associations of rs900400 and rs9883204 with birth weight in 393 families from the US, 265 families from Argentina, and 735 mother-infant pairs from Denmark. Z-scores adjusted for infant sex and gestational age were generated for each population separately and regressed on allele counts. Association evidence was combined across sites by inverse-variance weighted meta-analysis. Each additional C allele of rs900400 (LEKR1/CCNL1) in infants was marginally associated with a 0.069 SD lower birth weight (95% CI, -0.159 to 0.022; P = .068). This result was slightly more pronounced after adjusting for smoking (P = .036). No significant associations were identified with rs9883204 or in maternal samples. These results indicate the potential importance of this marker on birth weight regardless of gestational age.
    The Journal of pediatrics 08/2011; 160(1):19-24.e4. · 4.02 Impact Factor

Publication Stats

2k Citations
651.47 Total Impact Points

Institutions

  • 2003–2015
    • University of Pittsburgh
      • • Division of General Obstetrics and Gynecology
      • • Department of Obstetrics, Gynecology and Reproductive Sciences
      • • Department of Epidemiology
      Pittsburgh, Pennsylvania, United States
  • 2003–2014
    • Magee-Womens Hospital
      • Department of Obstetrics
      Pittsburgh, Pennsylvania, United States
  • 2013
    • University of British Columbia - Vancouver
      • Department of Obstetrics and Gynaecology
      Vancouver, British Columbia, Canada
  • 2011
    • University of Iowa
      • Department of Pediatrics
      Iowa City, Iowa, United States
    • University of Texas Medical Branch at Galveston
      • Department of Obstetrics and Gynecology
      Galveston, TX, United States
    • University of Rochester
      • Department of Obstetrics and Gynecology
      Rochester, NY, United States
  • 2010
    • Eunice Kennedy Shriver National Institute of Child Health and Human Development
      Maryland, United States
    • University of Texas Health Science Center at Houston
      Houston, Texas, United States
  • 2009
    • Northwestern University
      • Department of Obstetrics and Gynecology
      Evanston, IL, United States
  • 2008
    • University of Maryland, Baltimore
      Baltimore, Maryland, United States
    • Vanderbilt University
      • Department of Medicine
      Nashville, MI, United States
  • 2007
    • University of Washington Seattle
      • Department of Obstetrics and Gynecology
      Seattle, Washington, United States
    • University of Utah
      • Department of Obstetrics and Gynecology
      Salt Lake City, UT, United States
    • National Institute of Child Health and Human Development
      Maryland, United States