Stephen Todd Chasen, M.D.

Stephen Chasen

My clinical practice focuses on two main areas: prenatal diagnosis of fetal abnormalities, and consultation in managing complicated pregnancies. Our ultrasound unit has special expertise in first-trimester ultrasound and risk assessment for fetal chromosomal abnormalities, such as Down syndrome. We also offer expert prenatal diagnosis with second-trimester ultrasound. When indicated, I perform Chorion Villus Sampling (CVS) and amniocentesis.


Because many complications of pregnancy can be avoided or minimized by steps taken prior to pregnancy, I am also available for preconception counseling.

Medical School Jefferson Medical College, 1992 Residency OBGYN 1992-1996, Thomas Jefferson University Hospital, Philadelphia, PA

Fellowship Maternal-Fetal Medicine 1996-1998, New York Hospital/Cornell Medical Center

Director of High-Risk Obstetrics, New York Weill Cornell Medical Center, 10/00 to present Associate Professor of Obstetrics and Gynecology, 2003-Present co-Director of OB/GYN Residency, 2004-Present


Insurance Plans Accepted

The following represents most of the managed care plans accepted by this physician. If your insurance carrier does not appear here please feel free to contact this physician or this physician's practice as they may have individual contracts not included on this site.

  • AETNA [Medicare]
  • Aetna - Weill Cornell [POS]
  • Affinity Health Plan
  • Empire Blue Cross/Blue Shield [Mediblue (Senior)]
  • Empire Blue Cross/Blue Shield [PPO]
  • Empire Blue Cross/Blue Shield [EPO]
  • Empire Blue Cross/Blue Shield [HMO]
  • Fidelis Care
  • Health First
  • Health Plus - Amerigroup
  • Medicare [Medicare]
  • Oxford Health Plans [Freedom]
  • Oxford Health Plans [Liberty]
  • Rockefeller University - CoreSource
  • United Health Care


1. Fishman SG, Maheshwari B, Chasen ST. Risk factors for preterm delivery with placenta previa. J Perinat Med 2011. Nov 16 [Epub ahead of print]

2. Chasen ST, Wasden SW. Sequential Testing for Down Syndrome: The impact on estimated risk. Prenat Diagn. 2012;32:138-41

3. Fishman SG, Chasen ST. Risk factors for emergent preterm delivery in women with placenta previa and ultrasound findings suspicious for placenta accreta. J Perinat Med. 2011;

4. Wasden SW, Adams BN, Chasen ST. Are age cutoffs still used to identify candidates for invasive testing for chromosomal abnormalities? J Reprod Med. 2011;56:113-6.

5. Chasen ST, Krantz D. Does timing of biochemistry in first-trimester aneuploidy risk assessment affect the gestational age at prenatal diagnosis and pregnancy termination? Prenat Diagn. 2010;30:1151-4.

6. Brandt JS, Downing AC, Howard DL, Kofinas JD, Chasen ST. Citation classics in obstetrics and gynecology: the 100 most frequently cited journal articles in the last 50 years. Am J Obstet Gynecol. 2010;203:355.e1-7.

7. Chasen ST. Clinical implications of first-trimester screening. Clin Lab Med 2010;30:605-11.

8. Peláez LM, Chasen ST, Baergen RN. The relationship between placental histology and cervical length in twin gestations. J Perinat Med. 2010

9. Fox NS, Chasen ST. First trimester pregnancy associated plasma protein-A as a marker for poor pregnancy outcome in patients with early-onset fetal growth restriction. Prenat Diagn. 2009;29(:1244-8.

10. Chasen ST, Kalish RB, Chervenak FA. Basic versus detailed sonography: what do we miss? J Ultrasound Med. 2009;28:1015-8.

11. Chasen ST, Martinucci S, Perni SC, Kalish RB.First-trimester biochemistry and outcomes in twin pregnancy. J Reprod Med. 2009;54:312-4.

12. Peláez LM, Gelber SE, Fox NS, Chasen ST Inappropriate use of vancomycin for preventing perinatal group B streptococcal (GBS) disease in laboring patients. J Perinat Med. 2009;37:487-9.

13. Fox NS, Bhavsar V, Saltzman DH, Rebarber A, Chasen ST. Influence of maternal body mass index on the clinical estimation of fetal weight in term pregnancies. Obstet Gynecol. 2009;113:641-5.

14. Fox NS, Shalom D, Chasen ST. Second-trimester fetal growth as a predictor of poor obstetric and neonatal outcome in patients with low first-trimester serum pregnancy-associated plasma protein-A and a euploid fetus. Ultrasound Obstet Gynecol. 2009;33:34-8.

15. Fox NS, Gelber SE, Kalish RB, Chasen ST. The recommendation for bed rest in the setting of arrested preterm labor and premature rupture of membranes. Am J Obstet Gynecol. 2009;200(2):165.e1-6.

16. Fox NS, Gelber SE, Chasen ST. Physical and sexual activity during pregnancy and near delivery. J Womens Health. 2008;17:1431-5

17. Fox NS, Brennan JS, Chasen ST.Clinical estimation of fetal weight and the Hawthorne effect. Eur J Obstet Gynecol Reprod Biol. 2008;141:111-4.

18. Fox NS, Gelber SE, Kalish RB, Chasen ST. History-indicated cerclage: practice patterns of maternal-fetal medicine specialists in the USA. J Perinat Med. 2008;36:513-7.

19. Trentacoste SV, Jean-Pierre C, Baergen R, Chasen ST. Outcomes of preterm premature rupture of membranes in twin pregnancies. J Matern Fetal Neonatal Med. 2008;21:555-7.

20. Fox NS, Gelber SE, Kalish RB, Chasen ST. Contemporary practice patterns and beliefs regarding tocolysis among U.S. Maternal-fetal medicine specialists. Obstet Gynecol. 2008;112:42-7.

21. Peláez LM, Fox NS, Chasen ST. Negative fetal fibronectin: who is still treating for threatened preterm labor and does it help? J Perinat Med. 2008;36:202-5.

22. Fox NS, Streltzoff J, Chasen ST. Spontaneous resolution of an adrenal mass seen on ultrasound at 17 weeks gestation. J Pediatr Hematol Oncol. 2008;30:405-6.

23. Fox NS, Huang M, Chasen ST. Second-trimester fetal growth and the risk of poor obstetric and neonatal outcomes. Ultrasound Obstet Gynecol. 2008;32:61-5.

24. Fox NS, Chasen ST.Comparison of clinical estimation of fetal weight at the beginning and end of labor. Int J Gynaecol Obstet. 2008;101:133-6.

25. Chasen ST, Perni SC, Kalish RB, Chervenak FA. First-trimester risk assessment for trisomies 21 and 18 in twin pregnancy. Am J Obstet Gynecol. 2007;197:374.

26. Rauch ER, Jean-Pierre C, Mohan-Saha A, Huang M, Chasen S. Inpatient management for a shortened cervix: who is really at risk? Am J Obstet Gynecol 2007;196:e43-4.

27. Fox NS, Jean-Pierre C, Predanic M, Chasen ST. Does hospitalization prevent preterm delivery in the patient with a short cervix? Am J Perinatol 2007;24:49-53.

28. Fox NS, Jean-Pierre C, Predanic M, Chasen ST. Short cervix: is a follow-up measurement useful? Ultrasound Obstet Gynecol 2007;29:44-6.

29. Chasen ST. Peripartum and perioperative management of the anticoagulated patient. Obstet Gynecol Clin North Am 2006;33:493-7.

30. Chasen ST, Kalish RB, Chervenak FA. Gestational age at abortion: the impact of first-trimester risk assessment for aneuploidy. Am J Obstet Gynecol 2006;195:839-42.

31. Chasen ST, Luo G, Perni SC, Kalish RB. Are in vitro fertilization pregnancies with early spontaneous reduction high risk? Am J Obstet Gynecol 2006;195:814-7.

32. Chasen ST, Perni SC, Predanic M, Kalish RB, Chervenak FA. Does a "vanishing twin" affect first-trimester biochemistry in Down syndrome risk assessment? Am J Obstet Gynecol 2006;195:236-9.

33. Chervenak FA, McCullough LB, Chasen ST. Further evidence for first-trimester risk assessment as an autonomy-enhancing strategy. Ultrasound Obstet Gynecol 2006;27:355.

34. Perni SC, Predanic M, Kalish RB, Chervenak FA, Chasen ST. Clinical use of first-trimester aneuploidy screening can replicate data from clinical trials. Am J Obstet Gynecol 2006;194:127-30.

35. Perni SC, Vardhana S, Kalish R, Chasen S, Witkin SS. Clara cell protein 16 concentration in mid-trimester amniotic fluid: Association with fetal gender, fetal G>A +38 CC16 gene polymorphism and pregnancy outcome. J Reprod Immunol 2005;68:85-90.

36. Sharma G, Gold HT, Chervenak FA, McCullough L, Alt AK, Chasen ST. Patient preference regarding first-trimester aneuploidy risk assessment. Am J Obstet Gynecol. 2005;193:1429-1436.

37. Chasen ST, Kalish RB, Gupta M, Kaufman J, Chervenak FA. Obstetric outcomes after surgical abortion at > or = 20 weeks' gestation. Am J Obstet Gynecol 2005;193:1161-4.

38. Perni SC, Kalish RB, Hutson JM, Karasahin E, Bongiovanni AM, Ratushny V, Chasen ST, Witkin SS. Differential expression of immune system-related components in midtrimester amniotic fluid from singleton and twin pregnancies. Am J Obstet Gynecol. 2005;193:942-6.

39. Predanic M, Perni SC, Chasen ST, Baergen RN, Chervenak FA. Ultrasound evaluation of abnormal umbilical cord coiling in second trimester of gestation in association with adverse pregnancy outcome. Am J Obstet Gynecol. 2005;193:387-94.

40. Agrawala G, Predanic M, Perni SC, Chasen ST. Isolated fetal ascites caused by bowel perforation due to colonic atresia. J Matern Fetal Neonatal Med. 2005;17:291-4.

41. Chervenak FA, McCullough LB, Chasen ST. Clinical implications of the ethics of informed consent for first-trimester risk assessment for trisomy 21. Semin Perinatol 2005;29:277-9.

42. Predanic M, Perni SC, Chasen ST. The umbilical cord thickness measured at 18-23 weeks of gestational age. J Matern Fetal Neonatal Med 2005;17:111-6.

43. Predanic M, Perni SC, Friedman A, Chervenak FA, Chasen ST. Fetal growth assessment and neonatal birth weight in fetuses with an isolated single umbilical artery. Obstet Gynecol 2005;105:1093-7.

44. Chasen S, Spiro S, Kalish R, Chervenak F. Changes in fetal presentation in twin pregnancies. J Matern Fetal Neonatal Med 2005;17:45-8.

45. Predanic M, Perni SC, Chasen ST, Baergen RN, Chervenak FA. Assessment of umbilical cord coiling during the routine fetal sonographic anatomic survey in the second trimester. J Ultrasound Med 2005;24:185-91.

46. Kalish RB, Gupta M, Perni SC, Berman S, Chasen ST. Clinical significance of first trimester crown-rump length disparity in dichorionic twin gestations. Am J Obstet Gynecol 2004;191:1437-40.

47. Perni SC, Vardhana S, Korneeva I, Tuttle SL, Paraskevas LR, Chasen ST, Kalish RB, Witkin SS. Mycoplasma hominis and Ureaplasma urealyticum in midtrimester amniotic fluid: association with amniotic fluid cytokine levels and pregnancy outcome. Am J Obstet Gynecol 2004;191:1382-6.

48. Kalish RB, Vardhana S, Gupta M, Perni SC, Chasen ST, Witkin SS. Polymorphisms in the tumor necrosis factor-alpha gene at position -308 and the inducible 70 kd heat shock protein gene at position +1267 in multifetal pregnancies and preterm premature rupture of fetal membranes. Am J Obstet Gynecol 2004;191:1368-74.

49. Perni SC, Vardhana S, Tuttle SL, Kalish RB, Chasen ST, Witkin SS. Fetal interleukin-1 receptor antagonist gene polymorphism, intra-amniotic interleukin-1beta levels, and history of spontaneous abortion. Am J Obstet Gynecol 2004;191:1318-23.

50. Perni SC, Predanic M, Cho JE, Kalish RB, Chasen ST. Association of amniotic fluid index with estimated fetal weight. J Ultrasound Med 2004;23:1449-52.

51. Kalish RB, Thaler HT, Chasen ST, Gupta M, Berman SJ, Rosenwaks Z, Chervenak FA. First- and second-trimester ultrasound assessment of gestational age. Am J Obstet Gynecol 2004;191:975-8.

52. Sharma S, Perni SC, Predanic M, Kalish RB, Zervoudakis IA, Chasen ST. Atypical sonographic presentation of fetal unilateral inguinoscrotal hernia in a multiple gestation. J Perinat Med 2004;32:378-80.

53. Predanic M, Perni SC, Chasen S, Chervenak FA. Fetal aneuploidy and umbilical cord thickness measured between 14 and 23 weeks' gestational age. J Ultrasound Med 2004;23:1177-83.

54. Chasen ST, Kalish RB, Gupta M, Kaufman J, Rashbaum WK, Chervenak FA. Dilation and evacuation at ³20 weeks: comparison of operative techniques. Am J Obstet Gynecol 2004; 19:1180-3.

55. Chasen ST, McCullough LB, Chervenak FA. Is nuchal translucency screening associated with different rates of invasive testing in an older obstetric population? Am J Obstet Gynecol 2004;190:769-74.

56. Chervenak FA, McCullough LB, Skupski D, Chasen ST. Ethical issues in the management of pregnancies complicated by fetal anomalies. Obstet Gynecol Surv. 2003;58:473-83.

57. Al-Kouatly HB, Chasen ST, Kalish RB, Chervenak FA. Causes of thrombocytopenia in triplet gestations. Am J Obstet Gynecol. 2003;189:177-80.

58. Kalish RB, Chasen ST, Gupta M, Sharma G, Perni SC, Chervenak FA. First trimester prediction of growth discordance in twin gestations. Am J Obstet Gynecol. 2003;189:706-9.

59. Kalish RB, Vardhana S, Gupta M, Chasen ST, Perni SC, Witkin SS. Interleukin-1 receptor antagonist gene polymorphism and multifetal pregnancy outcome. Am J Obstet Gynecol. 2003;189:911-4.

60. Chasen ST, Sharma G, Kalish RB, Chevenak FA. First trimester screening for aneuploidy with nuchal translucency in a United States population. Ultrasound Obstet Gynecol 2003; 22:149-51.

61. Sharma G, Kalish RB, Troiano, R, Heier L, Chasen ST. Use of fetal MRI in patients electing termination of by dilation and evacuation. Am J Obstet Gynecol 2003;189:990-3.

62. Sharma G, Kalish RB, Chasen ST. Prognostic factors associated with antenatal subchorionic collection. Am J Obstet Gynecol 2003;189:994-6.

63. Kalish RB, Chasen ST, Rosenzweig L, Rashbaum WK, Chervenak FA. Impact of mid-trimester dilation and evacuation on subsequent pregnancy outcome. Am J Obstet Gynecol 2002;187:882-5.

64. Chasen ST, Al-Kouatly HB, Ballabh P, Skupski DW, Chervenak FA. Outcomes of dichorionic triplets. Am J Obstet Gynecol 2002;186:765-7.

65. Skupski DW, Gurushanthaiah K, Chasen S. The effect of treatment of twin-twin transfusion syndrome on the diagnosis-to-delivery interval. Twin Res 2002;5:1-4.

66. Al-Kouatly HB, Chasen ST, Ahner R, Gilbert F, Chervenak FA. Correlation between rare chromosomal abnormalities and prenatal ultrasound findings. Am J Med Genet 2002; 107:197-200.

67. Chasen ST, Skupski DW, Chervenak FA, McCullough LB. Prenatal informed consent for sonogram: the time for first trimester nuchal translucency has come. J Ultrasound Med 2001;20:1147-52.

68. Al-Kouatly HB, Chasen ST, Karam AK, Ahner R, Chervenak FA. Factors associated with fetal demise in fetal echogenic bowel. Am J Obstet Gynecol. 2001;185:1039-43.

69. Al-Kouatly HB, Chasen ST, Streltzoff J, Chervenak FA. The clinical significance of fetal echogenic bowel. Am J Obstet Gynecol. 2001;185:1035-8.

70. Chasen ST, Chervenak FA, McCullough LB. The role of cephalocentesis in modern obstetrics. Am J Obstet Gynecol. 2001;185:734-6.

71.Chasen ST, Al-Kouatly HB, Chervenak FA. Correlation between prenatal and neonatal birth order in twins. Am J Perinatol 2001.

72. Chasen ST, Madden A, Chervenak FA. Cesarean delivery of twins and neonatal respiratory disorders. Am J Obstet Gynecol 1999;181:1052-6.

73. Chasen ST, Loeb-Zeitlin S, Landsberger EJ. Hemoglobinopathy screening in pregnancy: comparison of two protocols. Am J Perinatol 1999;16:175-80.

74. Khabele D, Chasen ST. Cardiac tamponade: an unusual presentation of breast cancer in pregnancy. J Reprod Med 1999;44:989-91.

75. Chasen ST, Baergen R. Necrotizing funisitis with intrapartum umbilical cord rupture. J Perinatol 1999;19:325-6.

76. Borruto F, Chasen S, Chervenak FA, Fedele L. The Vecchietti procedure for surgical treatment of vaginal agenesis: comparison of laparoscopy and laparotomy. Int J Gynaecol Obstet 1999;64:153-8.

77. Lopoo JB, Hedrick MH, Chasen S, Montgomery L, Chervenak FA, Goldstein R, Hoffman WY, Harrison MR, Longaker MT. Natural history of fetuses with cleft lip. Plast Reconstr Surg 1999;103:34-8.

78. Chasen ST, Chervenak FA. What is the relationship between the universal use of ultrasound, the rate of detection of twin, and outcome differences? Clin Obstet Gynecol 1998;41:66-77.

79. Chasen ST, Silverman NS. Emergent cerclage: a ten-year single institution review. J Perinatol 1998;18:338-42.

80. Gorbe E, Chasen S, Harmath A, Patkos P, Papp Z. Very-low-birthweight breech infants: short-term outcomes by method of delivery. J MFM 1997;6:155-8.

81. Lagunowich LA, Schneider JC, Chasen S, Grunwald GB. Immunohistochemical and biochemical analysis of N-cadherin expression during CNS development. J Neurosci Res 1992;32:202-8.


Honors and Awards

American College of Obstetricians and Gynecologists Council on Resident Education in Obstetrics and Gynecology (CREOG) National Faculty Award: 2007, 2008, 2010, 2011


Donna Redel Clinical Scholar in Obstetrics and Gynecology, 2005-2011

Elected to Planned Parenthood NYC (PPNYC) Board of Directors: 2012