Residual follicle

A term used to describe masses or structures remaining in the ovary following a stimulation process during assisted reproduction techniques. Diagnosis is generally carried out using ultrasound imaging. 

Its origin is associated with: 

• The continued existence of a follicle(s) that did not ovulate.
• The late development of a follicle that continued growing following stimulation. 

Should ultrasound dimensions be above 3cm, it will be denominated residual cyst. 

The treatment of a residual follicle may consist of: 

• a wait-and-see approach: consists of waiting until the next menstruation and checking to see if it has disappeared.
• an active approach: consists of prescribing hormone contraception to block endogenous hormonal support and encourage the follicle to disappear.

 The condition will persist only in a limited number of cases and, when this occurs, specialist gynaecological intervention is required.