This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Hormone responsible for decidual reaction and Arias stella reaction in ectopic pregnancy is : \nSelect and explain. \nA. Oestrogen, B. Progesterone, C. HCG, D. HPL', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Arias stella reaction\n\nArias stella reaction is characterized by adenomatous change of the endometrial glands.\nCells loose their polarity, have hyperchromatic nucleus, vacuolated cytoplasm and occasional mitosis.\nThe reaction is seen in ectopic pregnancy (in 10 – 15% cases) and indicates blightening of conceptus be it intrauterine or extrauterine. (therfore it is not specific for ectopic pregnancy)\nIt occurs under the influence of progesterone.\n\nDecidual reaction :\n\nDecidua is the specialised highly modified endometrium of pregnancy.\nDecidual reaction/decidualisation is the conversion of secretory endometrium into decidua and is dependant on estrogen and progesterone.\nDecidual reaction is completed only with blastocyst implantation.\n\nSo, hormone which is common to both Arias stella reaction and decidual reaction is progesterone which is our answer of choice.', 'role': 'assistant'}]