Menstrual Cycle Phases
During a person’s menstrual cycle, the body develops and releases an egg in preparation of conception. The length and regularity of each person’s menstrual cycle may vary, and it can be a good indicator of fertility health.
At the Los Angeles Reproductive Center, we are happy to help patients from Encino, CA, Bakersfield, CA, and Los Angeles, CA, understand the different menstrual cycle phases, what role each phase plays in preparing the body for possible conception, and how that can impact fertility.
Many people think of their period as the end of their menstrual cycle, but in medical terms, the menstrual phase is actually the beginning. The menstrual phase starts when an egg released during the previous cycle is not fertilized. All of the tissues that were built up on the endometrial lining start to shed when conception does not take place. These tissues are released from the body through menstrual blood and mucus.
The length of the average menstrual phase is five to seven days, though this can vary significantly. During the menstrual phase you may experience a range of side effects, including:
- Sore, tender breasts
- Lower back pain
The follicular phase of the menstrual cycle actually overlaps with the menstrual phase. This phase starts on the first day of menstruation, and continues until ovulation. During the follicular phase, the pituitary gland releases follicle-stimulating hormone (FSH). This hormone promotes the production of follicles, small sacs of fluid which release regulatory hormones. Each contains an immature egg that may or may not mature. The body typically produces an average of five to 20 follicles each cycle. As they do, the body releases estrogen that thickens the lining of the uterus so it can support an embryo.
The average follicular phase lasts around 16 days, but again, this can vary. The follicular phase can be shorter with shorter cycles and longer for longer cycles.
As estrogen levels rise during the follicular phase, the pituitary gland starts to release luteinizing hormone (LH). This starts the ovulation phase of the menstrual cycle. During ovulation, a mature egg is released. It travels through the fallopian tubes to the uterus, where it is ready to be fertilized by sperm.
Ovulation lasts for about 24 hours, and it is the only part of the menstrual cycle during which you can become pregnant. Ovulation typically happens in the middle of a menstrual cycle, which would be around day 14 of an average 28 day cycle. Aside from ovulation tests, you can track ovulation by recording your basal body temperature (this increases slightly during ovulation), or by checking for thick discharge that has the texture of egg whites.
Once an egg has been released, the body enters the luteal phase of the menstrual cycle. The follicle changes into the corpus luteum. This releases hormones, like estrogen and progesterone, that keep the endometrium thick so it can support the implantation of a fertilized egg. If an egg does implant, the body will produce human chorionic gonadotropin, or hCG, which is an indicator of pregnancy.
If a person does not become pregnant, the corpus luteum will shrink and be resorbed by the body. Estrogen and progesterone levels will lower, which will trigger the start of menstruation. Common symptoms of the luteal phase include:
- Breast tenderness
- Mood swings
- Weight gain
- Increased appetite
Get a Fertility Evaluation
If you have an irregular menstrual cycle, or have had a difficult time conceiving, it may be time to schedule a fertility evaluation. To discuss your concern with the fertility specialists at the Los Angeles Reproductive Center, send us a message online at your earliest convenience or call (818) 946-8051.