The uterine lining which is formed as the maternal part of the placenta during the pregnancy is known as Decidua. It has highly characteristic cells and formed under the hormone influence so as to prepare the uterus for the implantation.
In mammals after the ovulation, the endometrial lining is transformed in secretory lining so as to prepare it for the embryo, In case if there is no implantation, the lining will shed as menstrual cycle or will be absorbed as estrous cycle. If implantation takes place then this lining known as deciduas evolves more during pregnancy phase.
About Decidual Cast
Whenever an area of the decidual is shed, it is termed as decidual cast as it generally comes out in uterine shape. Majority of the decidual cast cases are related to ectopic pregnancy and it can also be seen in women who are not pregnant as a side effect of using HCG, HMG and progestogens. These casts when grow without pregnancy can cause bleeding as well as pain in the abdominal area.
Causes of Decidual Cast
Use of Contraceptives
One of the reasons for the expulsion of the decidual cast is use of DMPA (Depot medroxyprogesterone acetate) which is a hormonal contraceptive.
Endometriosis is a problem where uterine tissues grow in the other regions of the pelvic cavity and in order to limit the tissue growth, doctors generally prescribe Progesterone. It has been found in a study that this female hormone can lead to decidual cast. Thus when Endometriosis is treated through use of progesterone, it can cause decidual cast.
One of the most common reasons associated with decidual cast is ectopic pregnancy which is a condition where the fertilized egg gets implanted outside the area of the uterine lining. A study also revealed that decidual cast can also be considered as an indication of the ectopic pregnancy.
Besides ectopic, general pregnancy can also cause decidual cast when at times the lesions on the uterine walls are formed. Though it is generally a rare condition but pregnancy can also lead to decidual cast.
Other important points associated with decidual cast:
- If you have an ectopic pregnancy with a decidual cast then during ultrasonography the condition can be often mistaken as intrauterine pregnancy. Thus in order to clear the doubts one should consult the doctor and get thorough checkup and also get serial of beta HCG levels checked.
- The expulsion of decidual cast can also be mistaken as miscarriage. The condition is also seen in those women who are not pregnant and this happens as a side effect of taking progesterone, HMG (human menopausal gonadotrophin) and HCG (human chorionic gonadotrophin).
- The use of combined oral contraceptive pills commonly does not cause the decidual cast of some specific shape, size and thickness. The condition of Membranous dysmenorrhoea is rare but if it happens then it causes severe cramping pain which is due to the passage of the cast through cervix which is undialated. Many women also experience bleeding during this condition.