<prompt> LH peak occurs how many hours before ovulation -36-48hrs.12-24hrs48-72hrs72-96hrs  <response>: Events Hours Oestraiol rise 83 Onset of LH surge 34-36 Oestraiol peak 24-36 LH peak 12-24 Progesterone rise 8 Approximate time interval of events in menstrual cycle prior to ovulation 