After the egg is released, the luteal phase of the menstrual cycle begins. The released egg has about 24 hours to get fertilized by waiting sperm, and this usually occurs just as the egg enters the fallopian tube. If you had had sex on the days of the LH surge, sperm should be there, waiting to greet the ovulated egg.
In the meantime, the LH hormone causes the ruptured follicle to become what is known as a corpus luteum. The corpus luteum's job is to keep releasing estrogen and to release a new hormone, progesterone. Estrogen encourages the lining of the uterus to keep growing, while the hormone progesterone helps the lining of the uterus become receptive to the fertilized egg.
