Specialties-Reproductive Endocrinology & Infertility:

  • Assisted Reproductive Technologies, including IVF
  • Polycystic ovarian syndrome
  • Endometriosis
  • Reproductive surgery
  • Uterine anomalies
  • Menstrual cycle abnormalities
  • Intrauterine insemination  (including donor sperm)
  • Oocyte donation (donor egg)


  • State of Oklahoma, 1997-present

Board Certification:

  • Obstetrics and Gynecology, 2006-present
  • Reproductive Endocrinology and Infertility, 2007-present


  • Ph.D. degree in microbiology and immunology at University of Oklahoma, 1995
  • M.D. degree at University of Oklahoma, 1997
  • Residency in Obstetrics and Gynecology at University of Oklahoma (1997-2001)
  • Fellowship in Reproductive Endocrinology and Infertility at University of Washington (2001-2004)

Research Interests:

  • Reproductive aging
  • Ovarian reserve testing
  • IVF
  • Polycystic ovarian syndrome

Current Research:

  • Reproductive aging in premenopausal women


Honors (selected):

  • James A. Merrill Award, Dept. of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center (1996)
  • Alpha Omega Alpha, University of Oklahoma College of Medicine (1996)
  • Lloyd and Ruth Rader Trust Scholarship for outstanding residents (1999)
  • Administrative Chief Resident, University of Oklahoma Health Sciences Center, Dept. of Obstetrics and Gynecology (2000-2001)
  • First Place Junior Fellow Scientific Oral Presentation, ACOG District VII Annual Meeting, St. Louis, MO., Oct 2-4:  Ovulation Induction with Metformin in Patients with Polycystic Ovarian Syndrome that Fail High-Dose Clomid. (2000)
  • APGO Excellence in Teaching Award, University of Oklahoma Health Sciences Center (2005)
  • Faculty Teaching Award, University of Oklahoma Department of Obstetrics and Gynecology (2005.2006,2007)
  • Prize Paper, ASRM 62nd Annual Meeting, New Orleans, LA., Oct 21-25:  The Decline in Ovarian Non-Growing Follicle Number from Birth to Menopause:  A New Model of Reproductive Aging. (2006)

Publications (selected):

Hansen, K.R., Morris, J.L., Thyer, A.C., and Soules, M.R., Reproductive Aging and Variability in the Ovarian Antral Follicle Count: Application in the Clinical Setting. Fertility and Sterility, 80(3), 577-583. 2003

Klein, N.A., Houmard, B.S., Hansen, K.R., Woodruff, T.K., Sluss, P.M., Verghese, T., Bremner, W.J., and Soules, M.R.,  Age-related Analysis of inhibin A, inhibin B, and activin A relative to the intercycle monotropic FSH rise in normal ovulatory women. J Clin Endocrinol Metab. 89(6), 2977-2981. 2004

Hansen, K.R., Thyer, A.C., Sluss, P.M., Bremner, W.J., Soules, M.R., and Klein, N.A.,  Reproductive aging and ovarian function-Is the early follicular phase FSH rise necessary to maintain adequate secretory function in older ovulatory women? Hum Reprod. 20(1), 89-95. 2005

Charleston, J.S., Hansen, K.R., Thyer, A.C., Charleston, L.B., Gougeon, A., Siebert, J., Soules, M.R., and Klein, N.A.  Estimating human ovarian non-growing follicle number:  the application of modern stereology techniques to an old problem.  Hum Reprod  22(8), 2103-2110. 2007

Hansen, K.R., Knowlton, N.S., Thyer, A.C., Charleston, J.S., Soules, M.R., and Klein, N.A.  A new model of reproductive aging:  the decline in ovarian non-growing follicle number from birth to menopause.  In press, Hum Reprod, 2008.

Hansen, K.R., Hodnett, G.M., Knowlton, N., and Craig, L.B.  Correlation of ovarian reserve tests with histologically determined primordial follicle number.  Fertility and Sterility 95(1), 170-175. 2011

Hansen K.R., Craig L.B., Zavy M.T., Klein N.A., and Soules M.R.  Ovarian primordial and non-growing follicle counts according to the stages of reproductive aging workshop (STRAW) staging system.  Menopause 19(2), 164-171. 2012

Huang H., Hansen K.R., Factor-Litvak P., Guzick D.S., Santoro N., Diamond M.P., Eisenberg E., Zhang H. Predictors of pregnancy and live birth after insemination in couples with unexplained or male-factor infertility.  Fertility and Sterility 97(4), 959-967. 2012

Hansen, K.R. Predicting reproductive age with biomarkers of ovarian reserve—how (and what) are we measuring?  Semin Reprod Med 31(6):416-26. 2013

Knowlton, N.S., Craig, L.B., Zavy, M.T., Hansen, K.R.  Validation of the power model of ovarian non-growing follicle depletion in women.  Fertility & Sterility 101(3):851-6. 2014

Zavy, M.T., Craig, L.B., Wild, R.A., Kahn, S.N., O’Leary, D.E., Hansen, K.R.  In high responding patients undergoing an initial IVF cycle, elevated estradiol on the day of HCG has no effect on live birth rate.  Reprod Biol Endocrinol. 28;12(1):119. 2014

Quaas, A.M., Weedin, E.A., Hansen, K.R.  Off-label medications used in the treatment of endometriosis.  Fertility and Sterility, 103(3):612-25. 2015

Karl Hansen, MD - OU Physicians Reproductive Medicine

Karl Hansen, MD, PhD