Everything that took place during the Follicular phase has prepared your body for a spectacular series of hormonal events that lead to ovulation. Ovulation occurs mid-cycle in response to a series of hormonal changes that are set off by a peak in estrogen, occurring any day from day 10 to 17 of the Follicular phase. This peak in estrogen triggers a brief surge in Luteinizing Hormone (LH), which triggers ovulation within usually 24 hours and occasionally up to 48 hours. Ovulation is the time when an egg is released from the dominant follicle (winner of the race) within an ovary, into the fallopian tube where it can become fertilized by sperm. This is the only time during the menstrual cycle that a woman can become pregnant. Women planning a pregnancy or using the “rhythm method” to prevent pregnancy often track their cycles using various methods such as body temperature, changes in vaginal secretions, and ovulation kits, also known as LH kits, to achieve pregnancy. If sperm are available, now is their chance! Once an egg is released, the egg is viable for up to 1 day, while sperm can be viable for up to 3 days. This means that the few days leading up to ovulation are the most fertile days of your cycle. With this in mind; conception is most likely to occur when sperm are available a few days prior to or just the following ovulation.
This part of the Ovulation Cycle lasts approximately 14 days. In this phase, the dominant hormone of the Follicular Phase estrogen declines, and progesterone levels increase. Estrogen’s job was to fertilize and promote the growth of the uterine lining and now progesterone’s job is to maintain that lining, or continue to “water the grass” so that a fertilized egg can implant or attach itself to the uterus. Progesterone levels are at their peak around 1 week after the LH surge, which coincides with the timing of embryo implantation, only if fertilization of the egg has occurred. The corpus luteum, which is what remains of the follicle in the ovary that released an egg at ovulation, is responsible for the increasing progesterone levels. Human Chorionic Gonadotropin (HCG) is secreted by the embryo and becomes detectable in urine and blood samples approximately 2 weeks following implantation, or 4 to 5 weeks following the first day of your last period. Increased levels of progesterone also signal the ovaries to not produce any more eggs at this time. If a fertilized egg has not attached itself to the uterine lining during the Luteal Phase, then progesterone levels will fall and the corpus luteum is reabsorbed a few days before your period starts. At the same time, the brain begins hormonal signaling all over again to prepare the next batch of follicles for their race to ovulation! An Ovulatory Cycle, better known as your Menstrual Cycle, begins again! Menstrual cycles are normally anywhere from 24 to 35 days, with an average cycle of 28-30 days This bleeding typically lasts about five days. Then, the monthly cycle repeats itself.
But some women have what is called abnormal uterine bleeding — another term for irregular periods — which can happen for a variety of reasons, from stress and lifestyle factors