[Prediction of ovulation]

Abstract

Predicting ovulation is the basis on which the fertile period is determined. When we carried out observations on 60 spontaneous cycles it was possible to detect with precision the discharge of LH which would produce ovulation by taking series of plasma levels of LH. The start is defined as the time when the level of LH becomes 180% greater than the mean level observed in the previous 24 hours. Ovulation occurs between 37 and 39 hours after this threshold has been crossed. The discharge of LH is the most constant criterion and the most precise one, and it does make it possible to work out the chronology of the events that precede ovulation. Ultrasound and estimation of levels of oestradiol in the plasma or in the urine do allow one to appreciate how the follicle is maturing.