Clinical Associate Professor Tan Lay Lok is a senior consultant obstetrician and gynaecologist with a special interest in obstetric medicine and high-risk pregnancy. Following his fellowship with Professor Michael de Swiet at Queen Charlotte’s Hospital, he has developed several multidisciplinary obstetric services caring for mothers with diabetes, cardiac, rheumatological, hematological, kidney and other medical conditions at the Singapore General Hospital.

He has peer reviewed publications and book chapters in these areas and organizes regular courses and meetings in maternal medicine and peripartum management. He has also been actively involved, either as chair or committee member, in holding international congresses in O&G for the OGSS, including the 2018 RCOG World Congress held in Singapore, and the 17th Singapore Malaysia Congress of Medicine with the theme of Relooking Women's Health in 2024 for the College of O&G Singapore. He is also a regular invited speaker at both local and regional meetings. 
Currently, he is the head of the Maternal Fetal Medicine department at the KK Women’s and Children’s hospital which oversees almost 12 thousand deliveries annually. He is also actively involved in undergraduate and postgraduate teaching and is also the Vice Chair of Education for the Singhealth OBGYN Academic Clinical Programme.

He was the  President of the College of Obstetricians and Gynecologists from 2021 to May 2025,  and oversaw the publication of several  guidelines including  the management of COVID-19 in pregnancy and COVID-19 vaccination in pregnancy. He is also the South East Asia representative for the International Society of the Obstetric Medicine.