Getting to know your menstrual cycle can help you learn about what’s happening inside your body. There’s more to it than your period, and those additional aspects can provide a wealth of knowledge when it comes to health patterns, possible illnesses and your fertility.
We spoke about all things cyclical with Rachel Urrutia, MD, an obstetrician-gynecologist at UNC Medical Center and assistant professor at the UNC School of Medicine.
The Menstrual Cycle
First, the basics on your cycle: A menstrual cycle is the series of events that occur between the first day of a period and the start of the next period. During that time the body goes through a cycle in which estrogen increases and spurs ovulation, which then produces progesterone to support a possible pregnancy. If there is no pregnancy, the hormone levels will drop and menstruation will occur.
The average menstrual cycle lasts 28 days, but cycles are still considered regular if they happen every 21 to 38 days. Most every woman’s cycle varies in some way, whether it’s how often ovulation happens, how long periods last or the severity of PMS (premenstrual syndrome) symptoms such as cramping, mood swings and fatigue.
The length of a woman’s cycles can differ from month to month and might change with age. The same can be said for period length and the amount of menstrual bleeding. The average period length is five days, but three to eight days is considered normal.
Many doctors “say ovulation is supposed to happen on day 14 of a cycle, but that only happens in 10 percent of all cycles,” Urrutia says. “Just because your pattern is different from the average doesn’t mean there is something abnormal that requires treatment. But for people who are having menstrual abnormalities, tracking their cycle can really help them get a better sense of their own pattern.”
Of course, tracking a menstrual cycle helps you time sex if you’re trying to conceive. But even for women who aren’t trying to get pregnant, tracking the cycle can reveal patterns of overall health.
For example, you might notice that you get migraines or feel fatigued during the same part of your cycle every month. Or, you might find out that you might have a different ovulation pattern—information that could help you if you want to get pregnant in the future. Getting to know your cycle can also help you identify changes that could be indications of a health issue.
A caveat: Women who use hormone-based contraception methods like the pill or IUDs (intrauterine devices) will not be able get an accurate picture of their fertility or health from keeping track of their cycle. These hormonal methods stop ovulation and alter or prevent typical cycle symptoms. Still, it’s a good idea for women using birth control to pay attention to bleeding patterns so they can spot anything unusual.
How to Track Your Menstrual Cycle
There are multiple ways to track a menstrual cycle and different tools to help understand that information. Here’s what to know:
The most basic way to track your cycles is to note the beginning and ending date of each period and how heavy or light it is. Keeping up with that information can help you pinpoint any changes or irregularities in cycle length.
A step beyond keeping track of the period is monitoring vaginal secretions, or cervical mucus, during a cycle.
A telltale sign of ovulation is mucus, Urrutia says. Before ovulation, estrogen levels are very high, and “there are receptors in the cervix that bind to the estrogen and create a different type of mucus, very wet and slippery. This usually happens three to seven days leading up to ovulation.”
After ovulation, progesterone levels rise, producing a thicker mucus, which may lead to women observing no mucus at all. About two weeks later, you should get your period.
Basal Body Temperature
Basal body temperature is the body’s lowest temperature during sleep. It’s usually taken right after waking up in the morning, using a digital oral thermometer or one specially designed to measure basal body temperature.
Taking this temperature every day is used to track changes in progesterone, Urrutia says.
“The increase in progesterone after ovulation can increase the body temperature very slightly,” Urrutia says. “When your body temperature is taken every morning consistently, you can figure out an average preovulatory basal temperature range. For most women, there should be about a half a degree increase from that basal temperature range after ovulation. This shift in temperature is the surest indication that you have ovulated.”
Basal body temperature can be affected by things like unusual sleep patterns or drinking too much alcohol the night before.
Some of the hormones responsible for your menstrual cycle can be measured in your urine. One important hormone for determining fertility is the luteinizing hormone (LH), which triggers the release of an egg from the ovary for ovulation. A big increase of LH in urine indicates that ovulation will happen within 24 to 48 hours, which are the two most fertile days for conceiving.
“This method is most helpful if you are tracking fertility to achieve or avoid pregnancy,” Urrutia says. “There are digital monitors available over the counter that will test urine and display hormone level results.”
What Your Cycle Can Tell You
Beyond being an indication of when to attempt to get pregnant—a woman is most likely to conceive just before or during ovulation—a menstrual cycle can be a window into overall health. After tracking several cycles, patterns might start to appear. Those seemingly random headaches and mood swings could be attributed to hormone fluctuation. Or, it might turn out that what is perceived as irregular discharge is actually quite normal mucus. However, Urrutia says the reverse is true as well.
“Irregular bleeding patterns can indicate a health issue. If you find that you are bleeding more frequently than every 21 days, bleeding less frequently than every 40 days, or having heavier than average periods that last eight days or longer, you should see a doctor,” she says.
Irregularity or absence of ovulation might be an indication of an issue like polycystic ovarian syndrome (PCOS), and is reason to talk to a doctor as well.
If a doctor’s visit is needed, Urrutia says it will usually include an ultrasound, Pap smear and testing for an infection. Some of the common causes of long or irregular periods include PCOS, polyps, fibroids, infection or pregnancy.
Urrutia says, “Tracking your cycles can also shed light on health issues that could happen in the future. Really long periods and PCOS are associated with increased rates of heart disease, diabetes and other long-term health risks.”
Getting Started with Tracking
First, start by keeping up with your period’s beginning and ending dates. You can do that on a paper calendar or use one of many apps available. But be careful when it comes to any predictions the app makes about your cycle.
“Many of the period tracker apps out there only track dates of your period and then predict a day that it thinks you ovulated. For women with very regular cycles it might be accurate,” Urrutia says, but it won’t help women with irregular cycles and very few of these apps have undergone testing to be sure that their predictions are accurate.
Some apps allow you to keep track of mucus and basal body temperature, which together produce a more accurate picture of what’s happening in your body.
While technology may be convenient, Urrutia advises that if you are tracking your cycle as a way to prevent pregnancy, there is only one app—Natural Cycles—that has been approved by the FDA as a fertility awareness-based method of contraception. Urrutia has led research on how little information is available to those who practice fertility awareness-based contraception, and she urges all women to learn more about contraception methods.
And if you’re looking to learn more about your body ahead of a possible pregnancy, tracking cycles is a great place to start.
“For women who want to learn more about their fertility, it’s a good way to gain more knowledge about how everything works,” Urrutia says.
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