<s>[INST] context: Endometrial biopsy Early secretory Subnuclear vacuolation (Ist HPE evidence of progesterone secretion) Seen on D16 of cycle Nuclei of glands gone up Stromal edema Late secretory Toous/ coiled glands All secretions in lumen of gland Cork screw glands( on D20 of cycle) Max stromal edema seen around D22of cycle) HPE of Proliferative endometrium Pseudostratification Long tubular glands Spinnbarkeit effect: ovulation mucus has the propey of great elasticity and will withstand stretching up to 10 cm. This phenomenon is called spinnbarkeit or the thread test for oestrogen activity. During the secretory phase, the cervical mucus becomes tenacious and its viscosity increases under the influence of progesterone so that it loses the propey of spinnbarkeit and fractures when put under tension. This propey is called tack. THIS LOSS OF SPINNBARKEIT EFFECT IS USED TO DIAGNOSE OVULATION RETROSPECTIVELY. Ultrasound: shows sudden reduction of follicle size (on serial USGs) and free fluid in Pouch of douglas. Endometrial thickness varies as follows early proliferative: thin bright echogenic stripe late proliferative: trilaminar appearance secretory phase: thick and uniformly echogenic [/INST] question: Which of the following findings is suggestive that ovulation has taken place? | options: A: Pseudostratification in endometrium B: Presence of Spinnbarkeit Phenomenon in cervical mucous C: Sudden reduction in size of follicle and free fluid in Pouch of Douglas on USG D: Trilamilar endometrium on USG | answer: C </s>