In psuedocyeis, what is the mechanism leading to abdominal distension?

The sign of pseudocyesis that is common to all cases is that the affected patient is convinced that she is pregnant. Abdominal distension is the most common physical symptom of pseudocyesis (63– 97% of women are found to experience this). The abdomen expands in the same manner as it does during pregnancy, so that the affected woman looks pregnant. This phenomenon is thought to be caused by buildup of gas, fat, feces, or urine. These symptoms often resolve under general anesthesia and the woman's abdomen returns to its normal size.

Pseudocyesis or phantom pregnancy is a condition where a non-pregnant woman believes that she is pregnant and has objective signs of pregnancy. Its exact pathogenetic mechanism is still unknown.

According to one study of 11 patients by Meza, et al 2 pseudocyesis was characterized by the following criteria:

1. Secondary amenorrhea [>12 weeks]

2. Two or more symptoms of pregnancy such as nausea, breast tenderness, abdominal distension, weight gain, etc.

3. Conviction of being pregnant and

4. A negative beta-HCG or pelvic ultrasound study.

Pathogenesis: According to Small, et al 3, 4 both psychological and neuro-endocrine mechanisms are involved in the development of pseudocyesis. A few of the conditions that may predispose to this kind of psychological disturbance resulting in pseudocyesis include recent pregnancy loss, history of infertility, rigid and orthodox society and cultural rituals that focus on child-bearing role of women and social isolation.

However, in some patients pseudocyesis may be a sign of some underlying organic disease such as systemic lupus erythematosus (SLE) 5 and schizophrenia. Patients with an underlying bronchogenic carcinoma may also sometimes, though rarely manifest with pseudocyesis. In these patients, pseudocyesis essentially represents a paraneoplastic syndrome occurring due to elevated levels of ectopic beta-HCG that is produced by the tumor.

Therefore, it should be kept in mind that not all patients presenting with pseudocyesis have pscyological disturbance but a rare few may also have some serious underlying organic disorder.