The most accurate way to determine the timing of ovulation is to track ovarian follicle development using ultrasound scanning. In this way, follicle growth can be directly seen with ultrasound and the precise timing of the LH surge determined using blood tests. This is called “cycle tracking” or “ovulation tracking”. Ultrasound scanning also provides other very valuable pieces of information, for instance, about ovarian reserve (the numbers of eggs in the ovary) and whether or not the womb lining is developing properly during the cycle. It will also identify other abnormalities in the womb that might affect pregnancy success such as fibroids and polyps.
Another option is to monitor for the LH surge in the urine. This is how ovulation detector kits work. When LH levels surge in the blood, LH is expected to enter the urine and to be detected using the kit.
The egg is released 1-2 days after the LH surge, so intercourse around the time of the LH surge will increase the chances for sperm to interact with the egg.