The abnormal pregnancy makes lower levels of HCG, which might be slow to detect.
The cause of pseudocyesis is not known but might be related to psychological or hormone dysfunctions, or occur in women who strongly want a baby but are having problems conceiving.
An ultrasound exam will show the absence of a baby.
A few of these women can curiously have a false positive pregnancy test.
Some even have symptoms of pregnancy, including morning sickness, a growing belly, and subsequent false labor pains.
It is especially important to make sure you don't have an ectopic pregnancy.