Bio

Clinical Focus


  • Diabetes, Gestational
  • Diabetes, Pregnancy-Induced
  • Nutrition During Pregnancy
  • Obstetrics and Gynecology

Academic Appointments


Professional Education


  • Fellowship:Stanford University - Fellowship (2014) CA
  • Professional Education:Stanford University Medical CenterCA
  • Residency:Northwestern University Feinberg School of Medicine (2010) IL
  • Board Certification: Obstetrics and Gynecology, American Board of Obstetrics and Gynecology (2011)
  • B.S., University of Illinois at Urbana-Champaign, Anthropology (2000)
  • Medical Education:University of Illinois College of Medicine (2006) IL

Teaching

Graduate and Fellowship Programs


Publications

Journal Articles


  • Risk factors for classical hysterotomy in twin pregnancies. Obstetrics and gynecology Osmundson, S. S., Garabedian, M. J., Yeaton-Massey, A., Lyell, D. J. 2015; 125 (3): 643-648

    Abstract

    To describe the rate of classical hysterotomy in twin pregnancies across gestational age and examine risk factors that increase its occurrence.This is a secondary analysis of the Cesarean Registry, a cohort study of women who underwent a cesarean delivery or a trial of labor after cesarean delivery at 19 academic centers between 1999 and 2002. Our study included all women with twin pregnancies and a recorded hysterotomy type who underwent cesarean delivery between 23 0/7 and 41 6/7 weeks of gestation. Primary exposures were gestational age at delivery and combined birth weight of twin A and twin B. Multivariate logistic regression was used to study factors thought to influence hysterotomy type including maternal age, body mass index (BMI) at delivery, obesity (BMI 30 or higher), nulliparity, labor, prior cesarean delivery, emergent delivery, and fetal presentation at delivery.Of 1,820 women meeting inclusion criteria, 125 (7%) underwent a classical hysterotomy. The risk of classical hysterotomy was greatest at 25 weeks of gestation (41%) and declined thereafter. The adjusted odds ratio (OR) for cesarean delivery declined as gestation age advanced (OR 0.87, 95% confidence interval 0.78-0.98). African American race and emergent delivery were associated risk factors for classical hysterotomy at 32 weeks of gestation or greater.Among women with twin pregnancies who deliver by cesarean, the incidence of classical hysterotomy is inversely related to gestational age but does not exceed 50% at any week; African American race and emergent delivery are associated risk factors at 32 weeks of gestation or greater.: II.

    View details for DOI 10.1097/AOG.0000000000000693

    View details for PubMedID 25730228

  • In reply. Obstetrics and gynecology Girsen, A. I., Osmundson, S. S., Garabedian, M. J., Naqvi, M., Lyell, D. J. 2015; 125 (3): 740-?

    View details for DOI 10.1097/AOG.0000000000000712

    View details for PubMedID 25730244

  • Body Mass Index and Operative Times at Cesarean Delivery OBSTETRICS AND GYNECOLOGY Girsen, A. I., Osmundson, S. S., Naqvi, M., Garabedian, M. J., Lyell, D. J. 2014; 124 (4): 684-689
  • Maternal proteinuria in twin compared with singleton pregnancies. Obstetrics and gynecology Osmundson, S. S., Lafayette, R. A., Bowen, R. A., Roque, V. C., Garabedian, M. J., Aziz, N. 2014; 124 (2): 332-337

    Abstract

    To compare 24-hour urinary protein excretion in twin and singleton pregnancies not complicated by hypertension.We prospectively evaluated mean 24-hour urinary protein excretion in twin and singleton pregnancies between 24 0/7 weeks and 36 0/7 weeks of gestation. Women with urinary tract infections, chronic hypertension, pregestational diabetes, and renal or autoimmune diseases were excluded. Collection adequacy was assessed by urinary creatinine excretion adjusted for maternal weight.Adequate samples were obtained from 50 twin and 49 singleton pregnancies at a mean gestational age of 30 weeks. At collection, the two groups were similar with regard to maternal age, gestational age, body mass index, and blood pressure. Mean urinary protein excretion was higher in twin compared with singleton pregnancies (269.3±124.1 mg compared with 204.3±92.5 mg, P=.004). Proteinuria (300 mg/day protein or greater) occurred in 38.0% (n=19) of twin and 8.2% (n=4) of singleton pregnancies (P<.001). After adjusting for confounding variables, the difference in mean total protein excretion remained significant (P=.004) and twins were more likely to have proteinuria compared with singleton pregnancies (adjusted odds ratio 9.1, 95% confidence interval 2.1-38.5). Nineteen participants developed a hypertensive disorder at a mean of 7.7 weeks after the urine collection (range 2.6-14.5 weeks). After excluding these women, proteinuria was present in 43% of twin and 7% of singleton pregnancies (P<.001).Mean 24-hour urinary protein excretion in twin pregnancies is greater than in singletons. These data suggest a reevaluation of the diagnostic criteria for preeclampsia in twin pregnancies.: II.

    View details for DOI 10.1097/AOG.0000000000000383

    View details for PubMedID 25004349

  • Effect of glycemic control on maternal serum pregnancy-associated plasma protein a. Obstetrics and gynecology Yeaton-Massey, A., Osmundson, S. S., Norton, M. E., Tang, H., Currier, R. 2014; 123: 85S-?

    Abstract

    The objective of this study was to determine if pregnancy-associated plasma protein A (PAPP-A) is correlated with glycosylated hemoglobin A1C in women with and without pregestational diabetes.Retrospective cohort study of women with singleton pregnancies and an A1C collected within 4 weeks of first-trimester analyte screening. Pregnancies with aneuploidy or not continued beyond 20 weeks were excluded. We used American Diabetes Association guidelines to define glycemic control categories (prediabetes: A1C 5.7-6.4%; diabetes: greater than 6.5%). Analysis of variance was used to compare mean difference in logarithmic PAPP-A by glycemic control. Bivariate correlation between PAPP-A and A1C was examined using Pearson's correlation coefficient. Multiple logistic regressions were used to further understand the relationship between PAPP-A and A1C after controlling for age and the time interval between the two tests.There were 372 eligible women; 8.3% had diabetes and 10.0% had prediabetes by A1C. There were no significant differences in mean PAPP-A by glycemic control (no diabetes 0.0238, prediabetes 0.0680, diabetes 0.0010; P=.548). There was no significant correlation between A1C and PAPP-A across A1C values (r=-0.05, P=.35) or between A1C and PAPP-A in the subset of women with A1C values greater than 6.5% (n=31, r=-0.11, P=.56) and women who required medication to treat diabetes in the first-trimester (n=38, r=-0.24, P=.13). After adjusting for age, body mass index, and time between the two tests, a significant correlation was found between logarithmic A1C and PAPP-A among women who required medication to treat diabetes (P=.048).There is a negative correlation between A1C and PAPP-A, particularly in women who used medication to treat diabetes.

    View details for DOI 10.1097/01.AOG.0000447414.47045.07

    View details for PubMedID 24770289

  • Risk Factors for Classical Hysterotomy by Gestational Age OBSTETRICS AND GYNECOLOGY Osmundson, S. S., Garabedian, M. J., Lyell, D. J. 2013; 122 (4): 845-850

    Abstract

    To examine the likelihood of classical hysterotomy across preterm gestational ages and to identify factors that increase its occurrence.This is a secondary analysis of a prospective observational cohort collected by the Maternal-Fetal Medicine Network of all women with singleton gestations who underwent a cesarean delivery with a known hysterotomy. Comparisons were made based on gestational age. Factors thought to influence hysterotomy type were studied, including maternal age, body mass index, parity, birth weight, small for gestational age (SGA) status, fetal presentation, labor preceding delivery, and emergent delivery.Approximately 36,000 women were eligible for analysis, of whom 34,454 (95.7%) underwent low transverse hysterotomy and 1,562 (4.3%) underwent classical hysterotomy. The median gestational age of women undergoing a classical hysterotomy was 32 weeks and the incidence peaked between 24 0/7 weeks and 25 6/7 weeks (53.2%), declining with each additional week of gestation thereafter (P for trend <.001). In multivariable regression, the likelihood of classical hysterotomy was increased with SGA (n=258; odds ratio [OR] 2.71; confidence interval [CI] 1.78-4.13), birth weight 1,000 g or less (n=467; OR 1.51; CI 1.03-2.24), and noncephalic presentation (n=783; OR 2.03; CI 1.52-2.72). The likelihood of classical hysterotomy was decreased between 23 0/7 and 27 6/7 weeks of gestation and after 32 weeks of gestation when labor preceded delivery, and increased between 28 0/7 and 31 6/7 weeks of gestation and after 32 weeks of gestation by multiparity and previous cesarean delivery. Emergent delivery did not predict classical hysterotomy.Fifty percent of women at 23-26 weeks of gestation who undergo cesarean delivery have a classical hysterotomy, and the risk declines steadily thereafter. This likelihood is increased by fetal factors, especially SGA and noncephalic presentation.: II.

    View details for DOI 10.1097/AOG.0b013e3182a39731

    View details for Web of Science ID 000330446900017

  • Urachal Duct Carcinoma Complicating Pregnancy OBSTETRICS AND GYNECOLOGY McNally, L., Osmundson, S., Barth, R., Chueh, J. 2013; 122 (2): 469-472

    Abstract

    Degenerating myomas are common explanations for pain associated with abdominal masses in pregnancy. However, masses arising from other pelvic organs should be included in the differential diagnosis.We present a case of an abdominal mass in pregnancy that was originally misdiagnosed as a uterine leiomyoma. Attention to the patient's history along with judicious use of imaging modalities led to the correct diagnosis of urachal duct carcinoma. This was treated appropriately and resulted in a term vaginal delivery. We present a review of the literature on this tumor and its management in pregnancy.Urologic malignancies are rare but should be considered in the differential diagnosis for any woman presenting with pain and an abdominal mass in pregnancy. A multidisciplinary approach optimizes outcomes.

    View details for DOI 10.1097/AOG.0b013e318292a3ab

    View details for Web of Science ID 000330460000014

  • Second-Trimester Placental Location and Postpartum Hemorrhage JOURNAL OF ULTRASOUND IN MEDICINE Osmundson, S. S., Wong, A. E., Gerber, S. E. 2013; 32 (4): 631-636

    Abstract

    The purpose of this study was to assess whether low placentation in the second trimester is an independent risk factor for postpartum hemorrhage.A retrospective cohort study of women undergoing transvaginal sonography between 18 weeks' and 23 weeks 6 days' gestation was conducted. Patients were subdivided into three groups: low-lying placenta (0.1-2.5 cm), marginal previa (touching but not overlapping the os), and complete previa (covering the os). Low placentation was used as a descriptive for all cases (low-lying placenta, marginal previa, and complete previa) in this study. A group of randomly identified control patients with normal placentation was selected for comparison.During the period of study, 410 women with low placentation were identified. Compared to controls, patients with second-trimester low placentation had increased rates of postpartum hemorrhage and uterotonic use. These increased risks persisted even among women in whom the low placentation resolved (odds ratio, 2.72; 95% confidence interval, 1.46-5.07; odds ratio, 2.18; 95% confidence interval, 1.24-3.84).Women with a second-trimester diagnosis of low placentation are at increased risk of postpartum hemorrhage.

    View details for Web of Science ID 000317323600009

    View details for PubMedID 23525388

  • Elective Induction Compared With Expectant Management in Nulliparous Women With an Unfavorable Cervix OBSTETRICS AND GYNECOLOGY Osmundson, S., Ou-Yang, R. J., Grobman, W. A. 2011; 117 (3): 583-587

    Abstract

    To compare outcomes of labor between nulliparas with an unfavorable cervix who underwent either elective labor induction or expectant management beyond 39 weeks of gestation.We conducted a retrospective cohort study of nulliparous women with a singleton gestation who had an unfavorable cervix (modified Bishop score less than 5) and delivered between 2006 and 2008. One hundred two nulliparous women who underwent elective induction of labor between 39 and 40 5/7 weeks of gestation were compared with 102 nulliparous women who were expectantly managed beyond 39 weeks of gestation.The primary outcome, cesarean delivery, was not statistically different between women who were expectantly managed and those who underwent elective labor induction (34.3% compared with 43.1%, respectively, P=.16). Aside from the more frequent occurrence of meconium in the expectantly managed group (36.3% compared with 7.0%, P<.001), there were no significant differences in other maternal (eg, chorioamnionitis, operative vaginal delivery, third-degree and fourth-degree lacerations, postpartum hemorrhage) or neonatal (arterial cord pH less than 7.0, Apgar score less than 7 at 5 minutes, neonatal intensive care unit admission) outcomes. Women who underwent an elective induction of labor did have longer duration of labor and delivery between admission and delivery (median 16.5 compared with 12.7 hours, P<.001).For nulliparous women with an unfavorable cervix, elective labor induction increased utilization of labor and delivery resources but did not result in other significant differences in most clinical outcomes.

    View details for DOI 10.1097/AOG.0b013e31820caf12

    View details for Web of Science ID 000287649400010

    View details for PubMedID 21343761

  • Elective Induction Compared With Expectant Management in Nulliparous Women With a Favorable Cervix OBSTETRICS AND GYNECOLOGY Osmundson, S. S., Ou-Yang, R. J., Grobman, W. A. 2010; 116 (3): 601-605

    Abstract

    To compare outcomes of labor between nulliparous women with a favorable cervix who underwent either elective labor induction or expectant management beyond 39 weeks of gestation.A retrospective cohort study was conducted of nulliparous women with a singleton gestation who had a favorable cervix (modified Bishop score of at least 5) and delivered between 2006 and 2008. Two hundred ninety-four nulliparous women who underwent elective induction of labor between 39 and 40 5/7 weeks of gestation were compared with 294 nulliparous women who were expectantly managed beyond 39 weeks of gestation.The primary outcome, cesarean delivery, was similar between the two groups (20.8% compared with 20.1%, respectively, P=.84), a result that did not change in multivariable analysis. There were also no significant differences in other maternal (eg, chorioamnionitis, meconium, operative vaginal delivery, third- and fourth-degree lacerations, postpartum hemorrhage), or neonatal (arterial cord pH less than 7.0, Apgar score less than 4 at 5 minutes, neonatal intensive care unit admission) outcomes. Women who underwent an elective labor induction did have longer duration in labor and delivery between admission and delivery (median 12.7 compared with 9.0 hours, P<.001).For nulliparous women with a favorable cervix, elective labor induction has a similar chance of resulting in cesarean delivery as expectant management, although it appears to result in an increase in resource use.II.

    View details for DOI 10.1097/AOG.0b013e3181eb6e9b

    View details for Web of Science ID 000281176400007

    View details for PubMedID 20733441

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