Determination of the of Ovulation Time: Characterization and Evaluation of Hormone Levels Prediction Value

INTRODUCTION: The fertility time frame is narrow and highly variable. Knowing the date of ovulation can help women in family planning both for achieving pregnancy and for preventing it.

AIM: To assess the predictive value of estrogen and progesterone levels in determining ovulation time.

MATERIALS AND METHODS: Daily blood tests for hormone levels and ltrasound were measured in normo-ovulatory participants. Referenced ovulation day (D0) was determined by documented LH surge and the disappearance of the leading follicle. The following measures were examined: sharp decrease in estrogen levels on D0, slight decrease in estrogen levels on D-1 and progesterone levels on the D-1, D0 and the day after ovulation (D+1). Percentage of corelation to the documented ovulation was calculated for each parameter.

RESULTS: Of 215 cycles that were followed, 53 cycles contained the required data for ovulation determination. Mean age was 31.0±4.4 years and mean BMI was 21.9±3.3. Sharp decrease in estrogen levels was observed in 81.1% of the cases (1018.8±420.6 pmol/l to 401.0±180.9 pmol/l, D-1 to day D0, respectively), slight decrease in estrogen levels was observed in 61.1% of the cases (1440.7±516.4 pmol/l to 1018.8±420.6 pmol/l, D-2 to day D-1, respectively). Mean progesterone levels were 3.3 ±0.7 nmol/l, 5.0±1.4 nmol/l and 11.2±3.5 nmol/l on day D-1, D0 and after ovulation (D+1), respectively.

CONCLUSIONS: Increasing the number of parameters used to determine the date of ovulation is important and can increase the accuracy in determining the exact date of ovulation. Appropriate algorithm based on estradiol and progesterone monitoring may serve as alternative to ultrasound and LH monitoring for determining ovulation time.