Dr. Chang has been working in Singapore since 1994 at the KK Women's Hospital from (1994-1998) and in Thomson Medical Centre since 1998.
He was made a Consultant Obstetrician and Gynaecologist, Department of Maternal Fetal Medicine, KK Hospital in 1997 and was a Visiting Consultant to that Department from 1998 to 2006.
His interests are in the medical and surgical management of high risk pregnancies, ultrasound assessment of the at-risk fetus, invasive prenatal diagnostic procedures and gynaecological laparoscopic surgery.