Although some women conceive easily, many others are discouraged when they see that single negative line month after month. Even a couple months of trying can feel like a long wait for those who decide they are ready for a baby. By understanding how the body works, the hormones involved in conceiving, and the tools available to help track this process, we can increase the chances of having a successful pregnancy sooner!

The Four Phases of Your Cycle

Let’s start with the four phases of the menstrual cycle, which you may already be familiar with - menstrual, follicular, ovulatory, and luteal. These phases are governed by a few very important fertility hormones, which must be in communication in order for this process to run effectively. This communication line is known as the HPO axis and includes the hypothalamus, pituitary, and ovaries. Disruption in the communication between these organ systems or the hormones they produce can have far reaching effects on fertility. The hormone gonadotropin-releasing hormone (GnRH) is produced by the hypothalamus and is more of a back-stage manager. Although it’s not a hormone that we track, it governs the release of two other very important hormones we will discuss below, luteinizing hormone and follicle-stimulating hormone. In a healthy cycle, the total cycle length from start to finish should be around 28 days (the same length as the lunar cycle, which is a reminder of how interconnected the universe is!). 

• The first day of bleeding, or menstruation, is marked as cycle day 1. In a healthy cycle, the bleed should be heaviest for the first 1-3 days and then slowly taper off, ending on cycle day 5. In tracking with the lunar cycle, menstruation occurs with the new moon in 28.3% of individuals. 

• The follicular phase includes menstruation and ends with ovulation. It is a time of maturing and preparing the egg within the ovary as well as thickening the uterine lining for potential implantation. This phase normally ends around cycle day 14, when ovulation occurs. During the follicular phase (including menstruation), fertility hormones (estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone) are at baseline for the most part. Around cycle day 5, follicle-stimulating hormone (FSH) starts being secreted by the pituitary to initiate follicle growth in the ovaries - each follicle contains an egg. Over the course of the follicular phase, one follicle becomes the largest and most dominant and begins producing estrogen. Estrogen is responsible for thickening the uterine lining. This rise in estrogen occurs in the days leading up to ovulation and causes FSH to stop being produced and luteinizing hormone (also from the pituitary) to start being produced. Luteinizing hormone (LH) triggers ovulation and surges in the 24-36 hours before ovulation occurs. It’s possible for an individual to experience multiple LH surges during their cycle, without the successful release of an egg. If one attempt is not successful, the body will often try again. 

• Ovulation is the release of the mature egg from the ovary and into the fallopian tube and occurs around cycle day 14 in a healthy cycle. It is associated with the full moon when tracking with the lunar cycle. Once the egg has been released, a structure called the corpus luteum forms on the ovary and begins secreting progesterone. Progesterone is responsible for keeping the uterine lining intact. The corpus luteum will disintegrate around 14 days post ovulation if pregnancy does not occur and progesterone production will come to a halt. If progesterone does not rise following “ovulation”, it means that the attempt to release an egg was not successful and therefore a corpus luteum did not form. This is known as an anovulatory cycle. I think it’s important to note that menstrual-like bleeding can still occur without successful ovulation and that “Anovulation in a random population occurs in over a third of clinically normal menstrual cycles”, which can be confusing for those who believe they are ovulating and frustrating for those trying to conceive.

• Following ovulation, the luteal phase lasts between 10-14 days and ends with menstruation or pregnancy. If fertilization of an egg occurs, it travels down the fallopian tube and implants in the uterine lining between 8 and 10 days post ovulation. Progesterone should remain high, while estrogen should be above baseline.  The ratio of estrogen to progesterone is a delicate dance, with high levels of estrogen preventing progesterone from keeping the uterine lining intact for successful implantation. Estrogen dominance is a condition of high estrogen levels that can be impacted by diet and lifestyle factors. A luteal phase that is too short (less than 10 days) or too long (more than 14 days) can signal a potential imbalance between these hormones.

According to this article, “almost 45-50 percent of women do not know their fertile window”, which means half of us are missing ideal conception time! The fertile window is the period of time that a woman is able to conceive and is marked as the four days leading up to ovulation, ovulation day, and the day following ovulation (this is because sperm can survive for up to five days within the reproductive tract and the egg can survive for up to 24 hours).

Fertility monitoring devices can be incredibly helpful in guiding users to identify this fertile window. Inito is an amazing at-home fertility monitoring device, which tracks LH, FSH, estrogen, and progesterone through hormone metabolite concentrations collected via a urine sample. This sample is then analyzed on a single test strip that is inserted into a small device that connects to an i-phone. After the test strip processes, the Inito app compares concentration levels and inserts them into a table and graph for a user-friendly experience. It takes the guesswork out of the process and lets a person know when they are in their fertile window, when fertility is low, and even when “peak fertility” levels are detected. As estrogen levels begin to rise leading up to ovulation, Inito recognizes the rise from baseline and marks these days as “high fertility” days. “Peak fertility” is identified by a surge in LH, notifying users that ovulation is expected in the next 24-36 hours. Planning intercourse during “high” and “peak” fertility days provides the best chances for successful conception. Because Inito tracks progesterone, it also informs users of successful ovulation as well as anovulatory cycles (Inito fertility monitor 15% discount here).

Another amazing tracking device duo is the Oura ring and Natural Cycles app. One of the awesome features on the Oura ring is a basal body temperature measurement. Basal body temperature (BBT) is the body’s lowest measured body temperature after a period of rest (usually overnight). Basal body temperature can be used to track ovulation as estrogen causes body temperatures to be lower and progesterone causes body temperatures to rise. In the day or so following ovulation, BBT rises by .5 to 1 degree Fahrenheit, helping users identify successful ovulation. BBT is great as a cross-check tool, but alone it doesn’t give us enough time to prepare for conception, as ideally intercourse will occur every other day in the five days leading up to ovulation, as well as on ovulation day. This is where Natural Cycles comes in. The Oura app pairs with the Natural Cycles app to transfer BBT data. BBT measurements, menstruation tracking, and LH tracking (optional) are used to predict the fertile window and ovulation. In a study analyzing Natural Cycles, the “median TTP [time to pregnancy] is two cycles for the majority of sexually active women without features of subfertility (age <35, cycle length variation <5 days)”. The majority of women in the study (88.5%) were considered to have features of subfertility, however 88% of them still managed to conceive within 6 months using the Natural Cycles app.

Cervical mucus is another great cross-check tool. As estrogen levels increase leading up to ovulation, estrogenic mucus that resembles egg-white also increases.When egg-white cervical mucus (EWCM) is present, take it as a sign that you have entered your fertile window and should start trying to conceive. In this study, 6 days of the cycle were identified as having the highest amounts of estrogenic mucus, signaling the most fertile days. In addition to signaling the fertile window, EWCM plays an important role in conception - “cervical mucus accepts, filters, prepares, and releases sperm for successful transport to the egg and fertilization”. Those who don’t produce healthy or adequate cervical mucus may have a more difficult time conceiving. The rise in progesterone after ovulation then causes a drastic decrease in the production of cervical mucus, so the last day of visible egg-white can be used to help determine ovulation. When used in conjunction with the Inito Fertility Monitor or Oura + Natural Cycles, it gives a person a great sense of what is happening within the body!

To summarize, these are the signs to look for and track when trying to determine the fertile window: 

• Egg white cervical mucus - usually in the 5 days leading up to ovulation when estrogen levels rise
• “High fertility” and “peak fertility” as identified by a fertility monitoring device such as Inito or Natural Cycles - determined by increasing estrogen levels followed by a surge in luteinizing hormone (the LH surge can also be detected with ovulation predictor kits, “OPK’s”, that measure LH)
• A rise of .5 to 1 degree Fahrenheit when tracking basal body temperature (on the Oura app) to signal successful ovulation - in response to rising progesterone levels
• **Or a “confirmed ovulation” or rise in progesterone on Inito

While we all hope to have perfectly balanced hormones and a body that runs just like it “should”, that’s not the reality for many women. We are bombarded with food, an environment, and lifestyle that fuels hormonal imbalance and inflammation via stress, toxin overload, sleep deprivation, and unrealistic expectations. I think it’s important to note that as you become more aware of how your body is operating, if it is not operating exactly how you wish it would, there is SO much to be done to heal and nourish the body so that it CAN function properly. Becoming in tune with the body and your hormones is the first major step to a successful pregnancy, but it may not be the last. If you identify a short luteal phase, basal body temperatures that don’t rise, low progesterone levels, or a lack of cervical mucus production that’s okay! Become your biggest health advocate. Do the research, nourish your body, and keep hope that your time will come - because it will!