A. 0-6 hours.
B. 6-12 hours.
C. 12-24 hours.
D. 24-36 hours.
LH is one of the hormones produced by the pituitary gland. Ordinarily, it’s secreted at very low levels throughout your menstrual cycle. But once a developing egg follicle reaches a certain size — usually around the midpoint of your cycle — LH secretion surges to really high levels. This hormone surge is what triggers ovulation about 24 to 36 hours later.
LH surge is important because it initiates the beginning of ovulation and fertile period. If you’re trying to get pregnant, this is the best time for you to begin having unprotected sex.
Once the egg is released, it is only viable for about 24 hours. After that, fertile window is over. This makes it very important to be able to identify this best time to conceive.