Ovarian cysts are one of the most common reproductive disorders seen in female guinea pigs. The causation of these cysts forming is still unknown, however there is a high correlation between the incidence of cysts and increasing age of guinea pigs. This condition is believed to affect up to 80% of female guinea pigs by the age of 6 years! Guinea pigs as young as 1 or 2 years old have also been seen with ovarian cysts, with average formation between ages of 2 and 4 years old.

Guinea pigs with ovarian cysts also have a higher likelihood of developing other reproductive disorders such as abnormalities to the uterine lining, and uterine cancers.

What are ovarian cysts?

Cysts are fluid-filled structures that arise from ovarian or peri-ovarian structures. There are two main types of ovarian cysts seen in guinea pigs:

              Cystic rete Ovarii (serous cysts) – These are the most common type. These cysts can grow extremely large, and can potentially get so big they start compressing surrounding structures and organs, causing organ disfunction and extreme pain. This type of cystic fluid often contains higher concentrations of hormones estradiol and progesterone, which due to these hormonal changes can result in hairloss over the guinea pigs abdomen – one of the most common external signs of cystic ovaries.

              The second most common type of cyst are follicular cysts – these cysts arise from normal ovarian follicles that fail to ovulate. These follicles also produce higher concentrations of hormones that may result in alopecia (hairloss). Some other external signs you might see associated with these hormonal changes is crusty nipples and behavioural changes.

Signs of Cystic Ovaries in Guinea Pigs

Some guinea pigs may develop ovarian cysts and not display any outward signs, which can make it difficult to diagnose, or may be an incidental finding during other tests. Some guinea pigs may develop cystic ovaries and never have any health issues.

Some of the common signs associated with cystic ovaries include:

• Alopecia (hairloss) on both sides of the abdomen. This hairloss generally does not cause any itchiness and is evenly distributed on both sides.
• Crusty and sometimes enlarged nipples
• An enlarged, distended abdomen, sometimes in a ‘pear shape’.
• Pain or vocalisation when touching the abdomen
• Changes in behaviour such as increased aggression or excessive mounting of cage mates.
• Weight gain OR weight loss
• Vaginal discharge that may be associated with concurrent uterine pathology
• Large cysts may compress the gastrointestinal tract causing anorexia, weight loss or reduced faecal production
• Reduced reproductive performance (inability to fall pregnant)

How do I find out if my guinea pig has cystic ovaries?

It is important to book an appointment with your veterinarian if you suspect your guinea pig has ovarian cysts. Diagnosis is usually made via ultrasound to detect the abnormal fluid filled structures. If large enough some vets may be able to palpate the cysts.

What is the treatment for Ovarian Cysts in Guinea Pigs?

Surgical removal of the female reproductive tract (also known as ovariohysterectomy) is the treatment of choice. This procedure is also referred to as ‘Spey’ or ‘desexing’. This surgical procedure MUST be performed by a registered veterinary surgeon.

It is sometimes opted to drain the cysts via a procedure called 'aspiration'. This is only a temporary measure to alleviate pain, and the cysts will eventually return anywhere from a few days to a few weeks. Some veterinarians may choose this method for guinea pigs in which surgical intervention is not advisable, particularly if they have other concurrent underlying health issues. There are also risks associated with aspiration, especially if one of the cysts burst inside the abdomen, and can result in death. 

 How do I prevent my guinea pig from developing ovarian cysts?

The only known way to prevent the formation of ovarian cysts and other uterine pathology is to desex your female guinea pig and remove the ovaries and uterus. We recommend doing this in younger animals who are healthy with no underlying health conditions, as they can  often tolerate the anaesthetic and surgery much better and have a faster recovery with less chance of post-operative complications.