The Empty follicle syndrome (or EFS) is a medical condition when there are no oocytes (eggs) in mature ovarian follicles, even though ultrasound and estradiol tests (the primary female hormone which is important for reproductive health) show the presence of well-developed follicles. Usually, empty follicle syndrome is diagnosed only during the IVF cycle.

It’s rather difficult to determine EFS at once. Even after the doctor has diagnosed such problem patient’s organism shows apparently normal follicular development and estradiol level. And even after controlled ovarian hyperstimulation (COH) for the in vitro fertilization cycle all medical tests stay normal. And it’s possible to fix empty follicle syndrome only after follicles will be taken and examined by medical specialists.

The EFS was originally described in 1986 and until nowadays all clear causes and mechanisms responsible for EFS still remain to be opaquing. It’s rather complex phenomenon with incidence rate of only 0.2–7%.


At the same time, some medical researchers believe the EFS disease is not a true syndrome at all. Doctors say that it can be just abnormal process that simply accompanies other primary pathological conditions. Fertility specialists assure that even in a normal cycle, without any hormone stimulation, not all follicles produce eggs and nearly 20% of normal follicles may be empty.

Risk factors for Empty follicle syndrome

The risk factor for Empty follicle syndrome increases with age of the potential mother.

Recent researches show that there are about 24% of patients aged 35 – 39 years old suffer from EFS and 57% of women who are over 40 years old face with EFS. Among women under 35 years old EFS is mostly an accident than regularity.