Dr. Greg Ryan is a perinatologist at Mount Sinai Hospital, Toronto.

His main interests are in the areas of high-risk pregnancies, obstetric ultrasound, fetal anomalies, monochorionic (identical) twin complications and fetal therapy, including in utero laser treatment to resolve twin-twin transfusion syndrome (TTTS), fetal chest and bladder shunting, fetoscopic tracheal occlusion for severe congenital diaphragmatic hernia (CDH), fetal spina bifida surgery and cardiac interventions, all firsts in Canada.

Dr. Ryan has consulted nationally and internationally. He has published more than 150 articles in peer-reviewed journals.