Fertility Basics: Understanding Your Cycle


Although our cycles comes each month, we may not be aware of all of the moving pieces involved in a typical 28-day period. There are four primary phases of the average menstrual cycle, with each playing an important role in your chances of conception, pursuing fertility treatment, and understanding any abnormalities.

Phase 1: Menstruation. The 28-day cycle always begins with – you guessed it – menstruation. The start of bleeding starts the menstrual cycle. Bleeding occurs between cycle days 1-7 on average, but can be longer or shorter depending on the individual.

Phase 2: Follicular Phase. During this phase of the cycle, your brain’s pituitary gland triggers the release of a follicle-stimulating hormone (FSH) and  encourages the ovaries to produce several follicles that form eggs. Usually, one egg grows to maturity while the others get reabsorbed into the ovaries. That one mature egg awaits fertilization from sperm, and brings us to our next phase.

Phase 3: Ovulation. The quickest phase in the entire cycle, ovulation provides a very short window of 24 hours for the egg to be fertilized. A luteinizing hormone (LH) is released to trigger ovulation and release the mature egg down the fallopian tube to meet with sperm. If sperm and egg are fertilized and implanted into the uterus, that begins pregnancy.

Phase 4: Luteal Phase. The luteal phase takes place in the second half of the cycle, post ovulation. During this time, hormones like estrogen and progesterone are elevated to support the potential pregnancy. If no pregnancy is established, the hormones decrease, and your menstrual cycle starts all over again. If pregnancy is established, human chorionic gonadotropin (HCG) hormones can now be detected through bloodwork.

How your menstrual cycle affects fertility

All women are unique and so is their cycle. Just because your cycle isn’t the typical 28 days, it doesn’t mean that something is necessarily wrong. Understanding if your cycle is regular (28 days), shorter, or longer, can impact timing of ovulation. Not knowing when you ovulate can make conceiving difficult, as there are only a few days out of the month where fertilization is possible. Using at-home LH kits can help detect ovulation, but many women find it helpful to see a fertility specialist for closer monitoring. Additionally, all fertility testing and treatment begins at day one of your cycle for the most accurate cycle monitoring and results.   

Getting in touch with your cycle can be a powerful way to better understand your fertility. And as always, your South Jersey Fertility Center provider can help support you in better monitoring and tracking.

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