By: Marisa Kahlich, L.Ac MSAOM
We partnered with Marisa Kahlich, L.Ac MSAOM, Owner and Clinical Director of the Texas Center For Reproductive Acupuncture to explore the phases of the reproductive cycle!
These days, there’s quite a bit of confusion around a woman’s cycle...
This includes how ovulation works, and how different factors impact our fertility health. Many of us were never taught what a healthy cycle or menses should ideally look like or which red flags to look out for. Your monthly cycle, referred to by some as the fifth vital sign, gives you important clues about your overall health and can alert you if something’s out of whack. More importantly, the ability to detect irregularities early on can help you to take proactive steps toward improving overall health and regulating your cycle while supporting fertility now and into the future. In fact, all women should be encouraged to gain a basic understanding of what a healthy cycle looks like and listen to the messages their bodies are sending.
The Follicular Phase
Your cycle consists of several key phases, the first being the follicular phase, which starts with your period and ends with ovulation. Named for egg development, this phase begins with cycle day one — your first day of full-flow — and should last approximately 2 weeks (10-17 days). It can also be shorter or much longer in someone with an irregular cycle. In an ideal cycle, your period should begin a brilliant bright red and last for approximately 4-5 days with little to no clotting, spotting, cramping or pain.
At the beginning of each new cycle, every woman starts with a base number of antral follicles (AFC) observable via ultrasound on each ovary. These follicles release anti-mullerian hormone (AMH). Both AFC and AMH can fluctuate in either direction from cycle to cycle, but do tend to decrease overall as we age; these changes don’t necessarily follow a linear path. In a natural, unmedicated cycle, a woman will typically have one dominant follicle emerge and grow leading up to ovulation. That said, it takes approximately 90 days for an immature follicle to produce a fully mature egg that is ready to ovulate. (Williams and Erickson) This is important, because what a woman does during that 3 month window can positively impact her follicles, regardless of her age. On occasion, a woman may have more than one mature follicle and hyperovulate, with a higher chance of conceiving multiples. Although rare in natural cycles, hyperovulation is more likely to happen in older women, due to heredity or as a result of taking fertility drugs.
Meanwhile, the brain’s hypothalamus releases hormones and growth factors via the pituitary to aid in egg development at the site of each ovary. Follicle stimulating hormone (FSH), for example, stimulates both the follicles to mature and the ovaries to release estrogen. Estrogen rises in accordance with the size and number of follicles developing and also plays a role in building and thickening the endometrial lining. We’ll circle back to why this is important when we get to the luteal, or progesterone-dominant, phase of the cycle.
Ovulation and the Fertile Window
Once estrogen peaks, assuming the follicle has reached full maturation — the pituitary halts production of FSH and releases luteinizing hormone (LH) as a signal to the ovary to release the egg. It’s around or during this time that women may notice the presence of fertile cervical mucus (CM) either on her clothing, or when wiping after using the restroom. Fertile CM is clear, sticky, or tacky, and resembles egg white. It’s most noticeable right before ovulation and is generally a positive sign of reproductive health. It also provides the perfect environment for sperm to live in — inside of the uterus and fallopian tubes. When no other signs are present, abundant CM may be your body’s natural way of communicating that ovulation is near.
Women may also use ovulation predictor kits and tests that measure surges in both estradiol and LH to help predict timing of ovulation. From initial surge, or peak, in LH, ovulation should occur approximately 36-40 hours later. However, this surge is not necessarily a guarantee of ovulation. Additionally, more affordable methods of tracking ovulation include measuring basal body temperature, checking cervical position, and the rhythm, or calendar, method. The calendar method works well for women who have a very predictable, regular cycle. Currently, it's easy to take advantage of the many phone apps and devices that use algorithms to predict ovulation based on your (and similar users’) unique cycle history. These forms of technology generally aim to make cycle and ovulation tracking simpler, more convenient, and less stressful. That said, all different methods range in accuracy, reliability, and convenience. Ultimately, finding the balance between using these tools effectively along with the clues provided by your body — and determining which ones work best — will look different for everyone.
Along with cycle tracking and planning, the best time to try to conceive is during the five-day fertile window leading up to ovulation, as sperm typically live in the fallopian tubes for 3-5 days. This window, however, may be longer for women who have less-predictable or irregular cycles. What’s more, if a couple is unsure of the quality of the male partner’s sperm, it’s best that they engage in trying every other day during their fertile window. If the sperm has been tested and is excellent, increasing the frequency of sex may be advantageous but can also lead to burnout. If the sperm is less than optimal, it’s best to try only once every 2 or 3 days to allow the sperm time to build back up. Mornings are also best for timing sex due to the fact that men have higher testosterone levels and sperm counts upon waking. (Ashok et al.) In preparation for ovulation, there should already be a collection of sperm in the fallopian tubes ready and waiting for the egg to drop. In the end, the egg should fertilize within 24 hours of ovulation, before it’s no longer viable. Unfortunately, trying to conceive post ovulation rarely results in positive pregnancy — timing is everything!
The Luteal Phase
Once ovulation is complete, an organ called the corpus luteum forms from the collapsed follicle that released the egg. This marks the beginning of the Luteal Phase, the progesterone-dominant phase of a woman’s cycle. Ideally, the corpus luteum should release progesterone for a minimum of 12-14, or up to 17 days. If the embryo implants successfully, it should continue to stimulate the corpus luteum via human-chorionic-gonadotropin (HCG) to keep producing progesterone. If HCG isn’t present, hormone levels will drop and the lining will begin to shed signaling the start of a new cycle via menstruation. When implantation successfully takes place, progesterone stays high and HCG will begin to rise. Some women see positive pregnancy tests days before a missed period, if implantation happens early enough. Additionally, a healthy, sufficient, trilaminar lining is imperative for this process to work. Adequate blood flow is also important, which is why fibroids and polyps can sometimes block embryo development.
While progesterone plays a key role in keeping the lining in-tact, it also helps the lining become receptive and ready to receive a healthy embryo. Most of the time, implantation happens approximately 8-10 days post ovulation. Although uncommon, some women may notice pain or spotting during this time. These symptoms may be brief, but they can also continue on into the first trimester of pregnancy and are not considered to be abnormal. Subchorionic hematoma is another common, relatively harmless reason some women experience bleeding in the first trimester. Every now and then, for some, it can be difficult to determine if these early symptoms are due to pregnancy or to an oncoming period. Most of the time, if a sperm and egg create an embryo that is chromosomally abnormal, or aneuploidy, it will not implant, but occasionally it might result in misscarrage. Even when a couple does everything right, they simply cannot control which sperm and which egg meet — which, again, is why it’s so important to support the health of our eggs and sperm throughout our reproductive years.
Ashok, Agarwal, et al. “A Unique View on Male Infertility around the Globe.” NCBI, April 2015, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4424520/. Accessed 5 April 2021.
Williams, Carmen, and Gregory Erickson. “Morphology and Physiology of the Ovary.” NCBI, January 2012, https://www.ncbi.nlm.nih.gov/books/NBK278951/. Accessed 1 April 2021.