Ramen H. Chmait, MD

Ramen Chmait, MD is Assistant Professor of Clinical Obstetrics and Gynecology, Pediatrics, and Surgery at the University of Southern California’s Keck School of Medicine. Dr. Chmait has served as director of Los Angeles Fetal Therapy since 2006. The Los Angeles Fetal Therapy is a program within the CHLA-USC Institute for Maternal-Fetal Health. In this capacity he has provided surgical treatment to hundreds of unborn children. Dr. Chmait also directs a research program devoted to understanding fetal disease and investigating potential treatment modalities.

• 2011
   -: U.S. News Top Doctors, 2011
   – 2014
• Fetal Hope: Light of Hope Award, 2008
• UCSD Department of Reproductive Medicine: Fellows Teaching Award, 2003
• Kaiser Permanente Los Angeles Medical Center: Resident Research Award, 2000

• Pre-Clinical Development of a Fetal Micropacemaker
  NIH · R01HD075135 · Sep 30, 2012 – Aug 31, 2017 · Role: Principal Investigator

• International Expert Consensus on the Diagnosis and Clinical Management of Primary Fetal Pleural Effusion. Prenat Diagn. 2026 Jul 14.. View in PubMed
• Fetal Echocardiography and Hyperoxia Testing after Serial Amnioinfusions: Results from the RAFT Trial Bilateral Renal Agenesis Arm. Fetal Diagn Ther. 2026 Jul 13; 1.. View in PubMed
• Neonatal Survival After Serial Amnioinfusions for Anhydramnios Due to Fetal Kidney Failure: The RAFT Clinical Trial. JAMA. 2026 Jul 01.. View in PubMed
• The Solomon Technique and Extreme Preterm Birth after Laser Surgery for Twin-Twin Transfusion Syndrome. Fetal Diagn Ther. 2026 Jun 30; 1.. View in PubMed
• Reply. Ultrasound Obstet Gynecol. 2026 Jun 12.. View in PubMed
• Technical Success of Fetal Aortic Valvuloplasty in Relation to Center Volumes: A Report From the International Fetal Cardiac Intervention Registry. Circ Cardiovasc Interv. 2026 Jun 09.. View in PubMed
• Prenatal diagnosis and management of monozygotic twins discordant for Turner syndrome – rare case of twin pathology. Ginekol Pol. 2026 Jun 09.. View in PubMed
• Sleep-related breathing disorders beyond infancy following open spina bifida repair. Eur J Pediatr. 2026 Jun 06; 185(7).. View in PubMed
• Does the order of ablation of vein-to-vein placental connections during fetoscopic laser photocoagulation affect outcomes in twin-twin transfusion syndrome? Am J Obstet Gynecol. 2026 May 23. Chmait RH . View in PubMed
• Mathematical reappraisal of the congenital cystic adenomatoid malformation volume ratio. J Matern Fetal Neonatal Med. 2026 Dec; 39(1):2654343.. View in PubMed
• Intrauterine hematoma evacuation during fetoscopic myelomeningocele repair: a novel application of the NICO Myriad. Neurosurg Focus Video. 2026 Apr; 14(2):V10.. View in PubMed
• Fetoscopic laser ablation vs standard management for Type-II and Type-III vasa previa. Ultrasound Obstet Gynecol. 2026 Mar; 67(3):320-328.. View in PubMed
• The role of superficial anastomoses on fetal survival after laser treatment for twin-twin transfusion syndrome: a subanalysis of the sequential trial. Am J Obstet Gynecol. 2026 Apr; 234(4):1214-1231.. View in PubMed
• Selective fetal growth restriction type II: IIb or not IIb. Am J Obstet Gynecol MFM. 2026 Jan; 8(1):101833.. View in PubMed
• Preoperative factors associated with donor twin demise in 1602 pregnancies complicated by twin-twin transfusion syndrome. Ultrasound Obstet Gynecol. 2025 12; 66(6):732-737.. View in PubMed
• Vasa previa: A condition with diverse management approaches. Best Pract Res Clin Obstet Gynaecol. 2025 Dec; 103:102674.. View in PubMed
• Rationale for the use of fetal ventriculosubgaleal shunts for the treatment of aqueduct stenosis. J Perinat Med. 2025 Nov 25; 53(9):1194-1197.. View in PubMed
• Feasibility and efficacy of vascular closure device for sealing uterine entry site: preliminary results from pregnant sheep model. Ultrasound Obstet Gynecol. 2025 10; 66(4):462-469.. View in PubMed
• Stage I twin-twin transfusion syndrome with intermittent umbilical artery Doppler abnormalities. Am J Obstet Gynecol MFM. 2025 Oct; 7(10):101754.. View in PubMed
• Current challenges in intrauterine management of obstructive fetal hydrocephalus and future directions. Ultrasound Obstet Gynecol. 2025 10; 66(4):401-412.. View in PubMed
• Fetoscopic Laser Surgery for Vasa Previa: Feasibility, Safety, and Future Directions. Clin Obstet Gynecol. 2025 09 01; 68(3):453-458.. View in PubMed
• Prevention of preterm birth in twin pregnancy: international Delphi consensus. Ultrasound Obstet Gynecol. 2025 06; 65(6):712-722.. View in PubMed
• Fetoscopic repair of open spina bifida between 26 0/7 and 27 6/7 gestational weeks and postnatal cerebrospinal fluid diversion. J Matern Fetal Neonatal Med. 2025 Dec; 38(1):2477770.. View in PubMed
• Monochorionic Twin Gestation. Clin Obstet Gynecol. 2025 09 01; 68(3):366-382.. View in PubMed
• Management and Outcomes in Isolated Congenital Aqueductal Stenosis: A Single-Center Retrospective Cohort Study. Prenat Diagn. 2025 04; 45(4):521-530.. View in PubMed
• Gestational age at birth varies by surgical technique in prenatal open spina bifida repair: a systematic review and meta-analysis. Am J Obstet Gynecol. 2025 Jun; 232(6):524-537.. View in PubMed
• Late Prenatal Development of Hindbrain Herniation in Open Spina Bifida. Fetal Diagn Ther. 2025; 52(4):429-438.. View in PubMed
• Vasa Previa: Prenatal Diagnosis and the Rationale Behind Using a 5 cm Distance from Internal Os. J Clin Med. 2025 Feb 05; 14(3).. View in PubMed
• The process of developing a comprehensive maternal-fetal surgery center. Am J Obstet Gynecol MFM. 2025 Jan; 7(1):101557.. View in PubMed
• Monitoring and management of hemolytic disease of the fetus and newborn based on an international expert Delphi consensus. Am J Obstet Gynecol. 2025 Mar; 232(3):280-300.. View in PubMed
• Cord Occlusion in Twin Reversed Arterial Perfusion Sequence: A Retrospective Study of Laser Photocoagulation versus Radiofrequency Ablation. Fetal Diagn Ther. 2025; 52(3):320-327.. View in PubMed
• Sleep-related breathing disorders in infants with spina bifida repaired prenatally and postnatally. J Clin Sleep Med. 2024 10 01; 20(10):1579-1583.. View in PubMed
• Increased Intrauterine Transfusion Blood Volume Needed to Correct Fetal Anemia due to Placental Chorioangioma. Fetal Diagn Ther. 2025; 52(1):90-96.. View in PubMed
• Safety of Intrauterine Transfusion Performed Beyond 34 weeks of Gestation. Prenat Diagn. 2024 12; 44(13):1614-1621.. View in PubMed
• Fetoscopic laser photocoagulation: a medically reasonable treatment option in the management of types II and III vasa previa. J Perinat Med. 2024 Nov 26; 52(9):927-933.. View in PubMed
• Randomized controlled trial of twin-twin transfusion syndrome laser surgery: the sequential trial. Am J Obstet Gynecol. 2024 09; 231(3):365.e1-365.e15.. View in PubMed
• Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus. Am J Obstet Gynecol. 2024 Dec; 231(6):638.e1-638.e24.. View in PubMed
• Consensus protocol for management of early and late twin-twin transfusion syndrome: Delphi study. Ultrasound Obstet Gynecol. 2024 03; 63(3):371-377.. View in PubMed
• Revisiting MOMS criteria for prenatal repair of spina bifida: upper gestational-age limit should be raised and assessment of prenatal motor function rather than anatomical level improves prediction of postnatal function. Ultrasound Obstet Gynecol. 2024 01; 63(1):53-59.. View in PubMed
• Neonatal Survival After Serial Amnioinfusions for Bilateral Renal Agenesis: The Renal Anhydramnios Fetal Therapy Trial. JAMA. 2023 12 05; 330(21):2096-2105.. View in PubMed
• Perinatal survival following intrauterine transfusion for red cell alloimmunized pregnancies: systematic review and meta-regression. Am J Obstet Gynecol. 2024 03; 230(3):e1-e2.. View in PubMed
• Third-trimester fetoscopic ablation therapy for types II and III vasa previa. Am J Obstet Gynecol. 2024 01; 230(1):87.e1-87.e9.. View in PubMed
• Outcome of laser photocoagulation in monochorionic diamniotic twin pregnancy complicated by Type-II selective fetal growth restriction. Ultrasound Obstet Gynecol. 2023 09; 62(3):369-373.. View in PubMed
• Fetoscopic Laser Ablation of Type II Vasa Previa: A Cost Benefit Analysis. Am J Perinatol. 2024 05; 41(S 01):e2454-e2462.. View in PubMed
• Subclassification of fetal growth restriction type IIa vs type IIb applied to twin-twin transfusion syndrome. Am J Obstet Gynecol MFM. 2023 09; 5(9):101082.. View in PubMed
• Prenatal repair of gastroschisis using partial carbon dioxide insufflation fetoscopy: lessons learned. Einstein (Sao Paulo). 2023; 21:eRC0543.. View in PubMed
• Multimodal Management of Cervical Insufficiency Complicated by Intra-amniotic Candida albicans Infection. Am J Perinatol. 2024 05; 41(S 01):e1463-e1469.. View in PubMed
• Advances in Fetal Surgical Repair of Open Spina Bifida. Obstet Gynecol. 2023 03 01; 141(3):505-521.. View in PubMed
• In utero Treatment of Congenital High Airway Obstruction Syndrome via Fetal Laryngoscopy and EXIT Procedure. Fetal Diagn Ther. 2022; 49(9-10):385-393.. View in PubMed
• Neuropathology Evaluation of in Utero Correction of Myelomeningocele and Complications of Late-Onset GBS Infection. Fetal Pediatr Pathol. 2023 Aug; 42(4):535-544.. View in PubMed
• Correction of fetal umbilical vein flow imbalance following laser surgery for twin-twin transfusion syndrome. Ultrasound Obstet Gynecol. 2022 12; 60(6):774-779.. View in PubMed
• Primum, non nocere: Whole blood, prehospital transfusion and anti-D hemolytic disease of the fetus and newborn. Transfusion. 2023 01; 63(1):249-256.. View in PubMed
• Solomon versus selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: A systematic review and meta-analysis. Prenat Diagn. 2023 01; 43(1):72-83.. View in PubMed
• Current Status of the Workforce and Training at Fetal Therapy Centers in North America. Fetal Diagn Ther. 2022; 49(7-8):333-339.. View in PubMed
• Design and Protocol of the Renal Anhydramnios Fetal Therapy (RAFT) Trial. Clin Ther. 2022 08; 44(8):1161-1171.. View in PubMed
• Percutaneous/mini-laparotomy fetoscopic repair of open spina bifida: a novel surgical technique. Am J Obstet Gynecol. 2022 09; 227(3):375-383.. View in PubMed
• Outcomes of laser surgery for stage I twin-twin transfusion syndrome. Prenat Diagn. 2022 Feb; 42(2):172-179.. View in PubMed
• Dual demise following laser surgery for twin-twin transfusion syndrome: Analysis of 52 cases at a single fetal surgery center. Prenat Diagn. 2021 Nov; 41(12):1548-1559.. View in PubMed
• Percutaneous fetoscopic spina bifida repair: effect on ambulation and need for postnatal cerebrospinal fluid diversion and bladder catheterization. Ultrasound Obstet Gynecol. 2021 Oct; 58(4):582-589.. View in PubMed
• Twin-twin transfusion syndrome and the definition of recipient polyhydramnios. Am J Obstet Gynecol. 2021 12; 225(6):683.e1-683.e8.. View in PubMed
• Experience of 300 cases of prenatal fetoscopic open spina bifida repair: report of the International Fetoscopic Neural Tube Defect Repair Consortium. Am J Obstet Gynecol. 2021 12; 225(6):678.e1-678.e11.. View in PubMed
• Fetal blood gases after in utero carbon dioxide insufflation for percutaneous fetoscopic spina bifida repair. Am J Obstet Gynecol MFM. 2021 09; 3(5):100409.. View in PubMed
• Complicated Monochorionic-Diamniotic Twins in a Pregnant Woman with COVID-19 in the Second Trimester. Am J Perinatol. 2021 06; 38(7):747-752.. View in PubMed
• The quantitative lung index: the left lung. J Matern Fetal Neonatal Med. 2022 Nov; 35(21):4142-4148.. View in PubMed
• Fetal neurodevelopmental recovery in donors after laser surgery for twin-twin transfusion syndrome. Prenat Diagn. 2021 01; 41(2):190-199.. View in PubMed
• Evaluation of cardiac function in the recipient twin in successfully treated twin-to-twin transfusion syndrome using a novel fetal speckle-tracking analysis. Prenat Diagn. 2021 01; 41(1):136-144.. View in PubMed
• Risk Factors for Co-Twin Fetal Demise following Radiofrequency Ablation in Multifetal Monochorionic Gestations. Fetal Diagn Ther. 2020; 47(11):817-823.. View in PubMed
• Twin-Twin Transfusion Syndrome Complicated by Proximate Placental Cord Insertion Sites: Endoscopic Clip-Assisted Laser Occlusion. Fetal Diagn Ther. 2020; 47(10):779-784.. View in PubMed
• Survival Outcomes by Fetal Weight Discordance after Laser Surgery for Twin-Twin Transfusion Syndrome Complicated by Donor Fetal Growth Restriction. Fetal Diagn Ther. 2020; 47(11):800-809.. View in PubMed
• Fetoscopic Laser Ablation Therapy for Type II Vasa Previa. Fetal Diagn Ther. 2020; 47(9):682-688.. View in PubMed
• Selective intrauterine growth restriction (SIUGR) type II: proposed subclassification to guide surgical management. J Matern Fetal Neonatal Med. 2022 Mar; 35(6):1184-1191.. View in PubMed
• Procedural, pregnancy, and short-term outcomes after fetal aortic valvuloplasty. Catheter Cardiovasc Interv. 2020 09 01; 96(3):626-632.. View in PubMed
• Percent Absent End-Diastolic Velocity in the Umbilical Artery and Donor Twin Demise after Laser Surgery for Twin-Twin Transfusion Syndrome. Fetal Diagn Ther. 2020; 47(7):572-579.. View in PubMed
• Perinatal Management of Bart’s Hemoglobinopathy: Paradoxical Effects of Intrauterine, Transplacental, and Partial Exchange Transfusions. AJP Rep. 2020 Jan; 10(1):e11-e14.. View in PubMed
• Risk Factors for Parenting Stress in Parents of Children Treated with Laser Surgery for Twin-Twin Transfusion Syndrome 2 Years Postpartum. Am J Perinatol. 2021 07; 38(9):944-951.. View in PubMed
• Amylase concentration and activity in the amniotic fluid of fetal rats with retinoic acid induced myelomeningocele. J Matern Fetal Neonatal Med. 2022 Jan; 35(1):147-154.. View in PubMed
• Antenatal course of referred monochorionic diamniotic twins complicated by selective intrauterine growth restriction (SIUGR) type III. J Matern Fetal Neonatal Med. 2021 Dec; 34(23):3867-3873.. View in PubMed
• Membrane Separation and Perinatal Outcomes after Laser Treatment for Twin-Twin Transfusion Syndrome. Fetal Diagn Ther. 2020; 47(4):307-314.. View in PubMed
• Is there a role for fetoscopic laser ablation therapy in Type-2 vasa previa? Ultrasound Obstet Gynecol. 2019 Nov; 54(5):696. Ibirogba ER, Shazly SA, Chmait RH , Ruano R . View in PubMed
• Delivery timing after laser surgery for twin-twin transfusion syndrome. J Perinatol. 2020 02; 40(2):248-255.. View in PubMed
• Uterine legacy of open maternal-fetal surgery: preterm uterine rupture. Am J Obstet Gynecol. 2019 11; 221(5):535.. View in PubMed
• Neurodevelopmental outcome of monochorionic twins with selective intrauterine growth restriction (SIUGR) type II: laser versus expectant management. J Matern Fetal Neonatal Med. 2021 May; 34(10):1513-1521.. View in PubMed
• Ultrasound-guided in Utero Transplantation of Placental Stem Cells into the Liver of Crigler-Najjar Syndrome Model Rat. Transplantation. 2019 07; 103(7):e182-e187.. View in PubMed
• Inadvertent Perforation of a Gravid Uterus During Laparoscopy. JSLS. 2019 Jul-Sep; 23(3).. View in PubMed
• Case 1: Cardiac Arrest in a 2-month-old Boy with a Prenatal Course Complicated by Alloimmunization. Pediatr Rev. 2019 May; 40(5):243-246.. View in PubMed
• Quantitative fetal fibronectin to predict spontaneous preterm delivery after laser surgery for twin-twin transfusion syndrome. Sci Rep. 2019 03 14; 9(1):4438.. View in PubMed
• Prenatal diagnosis and management of congenital complete heart block. Birth Defects Res. 2019 05 01; 111(8):380-388.. View in PubMed
• Characteristics of referred patients with twin-twin transfusion syndrome who did not undergo fetal therapy. Prenat Diagn. 2019 03; 39(4):280-286.. View in PubMed
• Percutaneous fetoscopic closure of large open spina bifida using a bilaminar skin substitute. Ultrasound Obstet Gynecol. 2018 Oct; 52(4):458-466.. View in PubMed
• The Use of Fetal Bronchoscopy in the Diagnosis and Management of a Suspected Obstructive Lung Mass. AJP Rep. 2018 Jul; 8(3):e195-e200.. View in PubMed
• Long-Term Outcomes After Thoracoamniotic Shunt for Pleural Effusions With Secondary Hydrops. J Surg Res. 2019 01; 233:304-309.. View in PubMed
• Response to Commentary by Saeid Safiri et al. J Matern Fetal Neonatal Med. 2020 01; 33(1):171.. View in PubMed
• Minimally Invasive Implantation of a Micropacemaker Into the Pericardial Space. Circ Arrhythm Electrophysiol. 2018 07; 11(7):e006307.. View in PubMed
• Iodine-Induced Fetal Hypothyroidism: Diagnosis and Treatment with Intra-Amniotic Levothyroxine. Horm Res Paediatr. 2018; 90(6):419-423.. View in PubMed
• Types II and III congenital pulmonary airway malformation with hydrops treated in utero with percutaneous sclerotherapy. Prenat Diagn. 2018 06; 38(7):493-498.. View in PubMed
• In utero Fetal Intubation for a Large Neck Mass: A Minimally Invasive EXIT Option. Fetal Diagn Ther. 2019; 45(4):275-280.. View in PubMed
• Re: Monochorionic diamniotic twin pregnancy with selective fetal growth restriction Type II: sonographic and fetoscopic findings of poor prognosis. Ultrasound Obstet Gynecol. 2018 02; 51(2):280.. View in PubMed
• Management of twin-twin transfusion syndrome with an extremely short cervix. J Obstet Gynaecol. 2018 Apr; 38(3):359-362.. View in PubMed
• The relationship between preoperative fetal head circumference and 2-year cognitive performance after laser surgery for twin-twin transfusion syndrome. Prenat Diagn. 2018 02; 38(3):173-178.. View in PubMed
• Risks of Preterm Premature Rupture of Membranes and Preterm Birth Post Fetoscopy Based on Location of Trocar Insertion Site. Am J Perinatol. 2018 07; 35(8):801-808.. View in PubMed