Cul de sac fluid is a common ultrasound finding in women of reproductive age and can be a normal finding or suggest a problem that needs to be investigated based on the context.
Cul de sac fluid normally accumulates after a follicle has ruptured and indicates a woman has ovulated. In some cases, excessive cul de sac fluid is a sign of an acute problem that needs to be addressed including a ruptured ovarian cyst, ovarian hyperstimulation syndrome (OHSS), or ectopic pregnancy.
FertilitySmarts explains Cul de Sac Fluid
The cul de sac is also known as the pouch of Douglas and is located between the uterus and the rectum. This area can fill with fluid released from the dominant follicle after it ruptures and ovulation occurs. In this context finding fluid in the cul de sac would be a normal finding.
Large amounts of fluid accumulation in this area may cause discomfort and affect fertility or with additional symptoms, can indicate a medical emergency such as ectopic pregnancy.
In women undergoing IVF treatment, ultrasound is used to track the stimulation of the ovaries and the maturation of eggs in preparation for retrieval. Sometimes the medications used to stimulate the ovaries can cause excessive stimulation in a serious condition known as ovarian hyperstimulation syndrome (OHSS) and a large amount of fluid may fill the cul de sac causing discomfort.