by Lindsey Szczepanski, NP
Some women are unaware of the very basics of fertility. Fundamentals like understanding the menstrual cycle and knowing when the fertile window takes place can influence a couple’s ability to conceive. That’s why it’s important for providers and patients alike to brush up on the nuts and bolts of fertility.
Menstrual Cycle Overview
First order of business in understanding fertility is to know the ins and outs of the menstrual cycle. The menstrual cycle has four phases—menstrual, follicular, ovulatory, and luteal. Each phase is important and disruptions in this cycle is the body’s way of expressing imbalance and a need for repair and restoration.
The first day of the menstrual cycle is the first day of bleeding (not when the bleeding ends). A normal menstrual cycle is considered 24-35 days, and the actual period (bleeding) itself typically lasts 3-7 days.
If you are actively tracking your cycle, congratulations! You are taking a big step forward in understanding your fertility. To determine your cycle length, call the first day of bleeding “day 1” and continue counting from there. Count the days until you begin bleeding again. The number of days between the start of your first period and the start of the next period is the length of your cycle.
The Menstrual Phase
Days 1-7 of the menstrual cycle are called the menstrual phase. This is when the uterine lining is shed (bleeding phase).
The Follicular Phase
The next phase of the menstrual cycle is called the follicular phase and takes place during days 8-14 of (approximately). During the follicular phase, the dominant follicle in the ovary starts to mature and grow in preparation for ovulation. Estrogen will start to rise in this phase.
The Ovulatory Phase
The ovulatory phase occurs during days 15-18 of the cycle (approximately). Estrogen will peak under the influence of luteinizing hormone (LH) releasing an egg from the dominant follicle. This is oftentimes accompanied by an increase in libido and energy, and an increase in cervical mucus that is thin, wet, and slippery.
The Luteal Phase
Days 16-28 of the cycle (approximately) are called the luteal phase and is when progesterone levels increase. The rise in progesterone during the second half of the menstrual cycle is a result of the the corpus luteum. Once the ovary releases the mature egg at ovulation from the dominant follicle that grew and matured during the follicular phase, the dominant follicle creates the hormone secreting structure known as the corpus luteum.
Progesterone only surges for 5-8 days of the month during the luteal phase. Estrogen levels drop down from the ovulatory surge, but remain higher than during the follicular phase. If pregnancy does not occur, the corpus luteum will start to disintegrate after about 10-14 days and progesterone and estrogen levels drop. This triggers the next period, and the menstrual phase of the cycle starts over again.
There is an intricate balance and fluctuation of hormones that interplay throughout the cycle and influence fertility. Each phase of the menstrual cycle is necessary for there to be a successful chance at conception. It’s best practice to test hormones between days 19-22 of the menstrual cycle to capture the mid-luteal peak of hormone levels.
Can I Get Pregnant All Month Long?
No. You cannot get pregnant all month long.
If you are trying to conceive, focus on those precious fertile days surrounding the ovulatory phase to optimize your chances of conceiving. If you are trying to avoid pregnancy, avoid intercourse during this six-day window or use a barrier method for prevention.
Some things to keep in mind. Sperm can live inside a woman’s body for up to five days. This means if you have unprotected intercourse during the five days leading up to ovulation, it is possible you will become pregnant (even if you had intercourse prior to the actual ovulation date).
Once ovulation occurs (this process can take 12-24hours) the egg released is only viable for approximately 24 hours. Therefore, having unprotected intercourse in the days before and during ovulation is the window of opportunity to get pregnant. These days offer your highest chances of conceiving.
You can track the phases of your cycle and learn when your fertile window will occur. Collecting data about your own menstrual cycle will give insight into your fertility and help you understand your overall health.
There are many free apps you can download on your phone to help you track your cycle. They record the first day of your period, as well as period length, and gather information about other symptoms you may experience throughout the month.
These apps can also alert you when your next cycle may be due, however they are not as accurate at predicting the fertile window or ovulation as other monitoring methods may be. Period tracker apps are helpful in keeping track of cycle length and regularity.
Ovulation Predictor Kits (OPKs)
OPKs predict ovulation by detecting increases in LH throughout the month. They work similarly to home pregnancy tests.
There are many different brands of OPKs on the market, so it is important to thoroughly read the instructions on how to test as each brand operates a little differently. Most commonly women will start testing on day 10 of their cycle and continue through day 18.
Cervical Mucus Quality
Cervical mucus (discharge) changes just before ovulation. The amount increases and becomes thin, wet, and slippery. After ovulation the mucus decreases and may become a little thicker and less noticeable.
Basal Body Temperature (BBT) Tracking
Tracking BBT is another great way to predict ovulation and fertile windows. The BBT method requires use of a thermometer under the tongue upon waking or before getting out of bed and monitoring cervical mucus changes throughout the cycle.
Using a BBT thermometer that reads to the hundredth degree is most accurate. To monitor your fertile window using BBT, it is best practice to take your temperature under the tongue at same time every day BEFORE getting out of bed. Prior to ovulation, the average BBT reading will be 97.0-97.5 degrees. After ovulation BBT rises to 97.6-98.6 degrees.
Understand Your Cycle for Greatest Fertility Success
Collecting information about and tracking your cycle is important for understanding your fertility. Another effective way to monitor your menstrual cycle is through DUTCH. The DUTCH Cycle Mapping™ test kit measures estrogen and progesterone levels throughout the entire cycle. This comprehensive dried urine test is great for women with irregular cycles or who are struggling with fertility.
With insights gleaned from the DUTCH Cycle Mapping, providers are in a better position to help their patients understand their fertility and work towards conceiving.
You can learn more about DUTCH Cycle Mapping here.