Decidual Cast: Cause, Symptoms, Prevention, Diagnosis

A decidual cast is a long piece of tissue that passes through the vagina and can affect the people who menstruate. The tissue is red in color and is triangle in shape and may look like the shape of the uterus. It can lead to extreme discomfort and vaginal bleeding on leaving the body.

Mostly the symptoms pass away as the cast leaves the body if they are not due to any other condition. The real cause of decidual cast is not known but it is thought to be related to hormonal contraceptive pills and ectopic pregnancy.

The decidual cast can be due to several reasons.

A pregnancy is called ectopic when the egg is fertilized outside the uterus. It is not a normal pregnancy and a medical emergency service should be contacted as it can pose a risk to the life of the female.

Females who are on a high dose of progesterone are at an increased risk of the decidual cast. The contraceptives can be in oral form as well as injectable.

The risk of a decidual cast can increase in those who have stopped taking or have been taking hormonal contraceptives inconsistently.

There are some other conditions that may lead to similar symptoms. These include;

• Pregnancy
• Miscarried pregnancy
• Intrauterine mass
• Polyps or skin tags
• Sarcoma botryoides, a tumor that develops within hollow organs
• Rhabdomyosarcoma, a soft cancer tissue

Studies show that a female may not have any long-term health impact after passing the decidual cast.⁽¹⁾

There may be bleeding, spotting, cramping and very severe abdominal pain, before the cast is expelled.

The cast expelled is pink or red and looks just like the uterus. It is because the entire lining of the uterus is exited in one piece. As it is made of tissues it appears fleshy. Sometimes the cast comes out in fragments instead of a single tissue piece.

The symptoms of the decidual cast are very similar to miscarriage as they also include cramping, bleeding, and loss of large tissue pieces. It is therefore important not to play a guessing game for the condition and consult a doctor.

Before coming to a diagnosis, the doctor discusses the health history and does a physical examination. He enquires about the duration and characteristics of symptoms.

If all the symptoms are of a decidual cast, a pelvic examination is not required. If no improvement is seen with the medical treatment, secondary dysmenorrhea is suspected. An ultrasound can be helpful in determining or differentiating the cause.

If the symptoms point toward sexually transmitted disease or pelvic inflammatory disease, a swab is suggested.

Imaging tests can be helpful in coming to a conclusion. The doctor may look for ectopic pregnancy or any unusual mass in the reproductive system. If none of the options reveal the cause of the symptoms, laparoscopy may be done.

Many people do not get medical attention for decidual cast due to embarrassment or the ability to self-manage. However, if there is extreme cramping and bleeding during the menstrual period a doctor should be consulted.

Decidual cast mostly occurs due to the side effects of contraceptive use.⁽²⁾ Therefore, before starting any hormonal contraceptive one should be aware of the possible side effects. While taking any contraception one should be mindful of the unusual symptoms such as severe cramps and excessive vaginal bleeding.

Expulsion of a decidual cast can be very painful and may cause concern in a few people. But its outlook is very good. This condition is rarely experienced multiple times. If experiencing symptoms a doctor should be consulted to determine the cause of the symptoms and go for additional testing if needed.