<prompt> In ectopic pregnancy decidua is shed as:Decidua veraDecidua basalisDecidua capsularisDecidua rubra  <response>: Ans. is a, i.e. Decidua veraRef. Shaw 14e, p 244Decidua vera is the parietal layer of decidua, that lines most of the uterine cavity.In ectopic pregnancyUnder the hormonal influence of Progesterone and estrogenUterine endometrium is converted toDecidua similar to Intrauterine pregnancyWhen the ectopic is interruptedLevels of progesterone and estrogen decreaseWithdrawal of support to uterine endometriumEndometrium decidua Shed off in the form ofDecidual cast-The passage of decidual cast is pathognomic of ectopic pregnancy.Q-Chorionic villi are characteristically absent in the decidua.Q-The presence of chorionic villi in the cast however rules out ectopic pregnancy and denotes uterine pregnancy.Also Know:Arias Stella Reaction is characterized by typical adenomatous changes of the endometrial glands seen under the influence of progesterone.It is not specific for ectopic pregnancy but rather indicates the blightening conceptus, either intrauterine or extrauterine --Dutta Obs 6e, p 183 