Baseline scan

A baseline scan is an ultrasound examination performed at the start of an IVF cycle, usually early in the menstrual cycle, to check that the ovaries are quiet (without residual cysts or unusually persistent follicles) and to assess the endometrial lining before ovarian-stimulating medicines are started. It also allows an antral follicle count to be recorded for that cycle. If the baseline scan shows a finding such as a cyst or an unexpectedly thick lining, the treating specialist may delay the start of stimulation or adjust the plan for that cycle. The baseline scan is a routine safety and planning step rather than a diagnostic test on its own.

Also known as: day 2 scan, day 3 scan

Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.