Pregnancy Calculator

Last Menstrual Period started on:
Your Average Length of Cycles:	(22 to 45 days)
Your Average Luteal Phase Length:	(9 to 16 days)

Estimated Conception Date:
Estimated Due Date:
Estimated Fetal Age:

The luteal phase is the period of time (usually 11-14 days) following ovulation.

The egg can be fertilized within 24 hours of release, while it is still in the fallopian tubes.

If the egg is fertilized, the pituitary gland produces hCG which causes the increased production of progesterone.

The progesterone in turn causes the BBT to remain high throughout the luteal phase and after the 14th day.

High progesterone levels are also responsible for "morning sickness" and other symptoms of pregnancy.

If the egg is not fertilized within 24 hours, the corpus luteum regresses and slows its progesterone production.

After around 11-14 days, there is no longer enough progesterone to supply the uterine lining with blood, and so menstruation begins anew.