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Published by Hera Fertility
Posted on
October 17, 2023
Read Time
7 mins
Oh, the menstrual cycle. It’s a natural, complex, and often mysterious journey that nearly every person with a uterus experiences at some point in their life.
Every month it’s a rollercoaster of hormones, emotions and physical changes that can leave even the most knowledgeable — and in-tune-with-their bodies — person feeling baffled at times.
This confusion extends down to the very definition of the menstrual cycle. “Some people might not know what a ‘cycle’ means, because we’re often taught that it’s your period,” says Cindy Golubisky, Clin Ops & Fertility Clinician at Hera Fertility.
But your period is just part of the whole menstrual process, one that typically lasts 28-34 days. Some people diligently track their cycles and know the precise date that their period will start. Others just let nature take its course and don’t spend too much time thinking about it, making their periods more of a surprise.
[Read our blog post: The truth about female infertility diagnosis and testing]
If you’re planning to get pregnant at some point, though, understanding your menstrual cycle is key. And for those seeking fertility help, one of the first questions you’ll be asked is: What day did your last period start?
“No matter what treatment somebody does, we always want to know what day they get their period, because that’s how we can instruct them, and guide them to what happens next,” Golubisky explains.
Whether you’re planning to get pregnant or not, knowing how the menstrual cycle works can be empowering: At any given time you can recognize what phase you’re in, and recognize the often subtle — but extraordinary— changes in your body.
So what’s really going on down there? Let’s break it down into the four main phases.
Menstrual Phase (Days 1-5): Setting the Scene
The first phase of the menstrual cycle is the “menstrual phase,” which is also known as your period. This might seem confusing, but remember: Your period is not your whole menstrual cycle — just a part of it.
The menstrual phase marks the shedding of the uterine lining, which was built up in anticipation of a potential pregnancy in the previous cycle. When conception doesn’t occur, the body says, “It’s time to start over.”
During this phase, estrogen and progesterone levels drop significantly. This drop triggers the release of prostaglandins, which cause the uterine muscles to contract and shed the uterine lining. This shedding can cause cramps, fatigue, mood swings, backaches and other uncomfortable symptoms.
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Follicular Phase (Days 6-14): Preparing for Ovulation
The next phase, which typically happens on Days 6 through 14, is the “follicular phase.” Here, your body begins the careful process of selecting a mature egg for ovulation. The pituitary gland releases follicle-stimulating hormone (FSH), prompting the ovaries to produce several follicles. Each follicle contains an immature egg.
The rise in estrogen during this phase also triggers the release of luteinizing hormone (LH), which revs up ovulation.
Ovulation (around Day 14): The Peak of Fertility
Ovulation, which typically occurs around the middle of the menstrual cycle, is when the mature egg is released from the dominant follicle into the fallopian tube.
Peak fertility begins now. If an egg meets sperm during this phase, conception is possible.
The hormones that orchestrate ovulation are quite remarkable. An increase in LH, often referred to as the “LH surge,” typically occurs 12-48 hours before ovulation. The LH surge causes the follicle to rupture, releasing the egg.
It can be difficult to pinpoint exactly when ovulation occurs in most women, notes Golubisky. “But we know that it happens somewhere around day 10 to 16, before the next period.” For those trying to conceive, LH surges can be detected using ovulation predictor kits.
[Read our blog post: Beyond the calendar: Four techniques for ovulation tracking]
In some cases you can actually notice signs of ovulation in your body: increased cervical mucus that resembles egg whites, heightened libido and even mild pelvic pain and cramping, known as mittelschmerz.
If you want to get pregnant, this is the time to start having sex.
Luteal Phase (Days 15-28): When Pregnancy is Most Possible
During this luteal phase, which lasts about 14 days, the empty follicle transforms into a normal cyston the ovary. Known as the corpus luteum, this structure produces estrogen progesterone. The latter hormone plays a vital role: Progesterone increases the size of the uterus and thickens the uterine lining to create the ideal environment for a fertilized egg to implant.
If an embryo implants in the uterine lining, the corpus luteum continues to produce progesterone to support the early stages of pregnancy. However, if fertilization doesn’t happen, the corpus luteum eventually breaks down and turns into a scar (corpus albicans), leading to a decrease in progesterone.
This hormonal drop signals to the body that pregnancy has not occurred, and it’s time to re-start the cycle. With no further support for the uterine lining, it begins to break down. And the menstrual phase begins again.
The Window of Fertility: Timing is Everything
The key to maximizing your chances of conception — or avoiding it — lies in pinpointing your fertile window: the days when conception is most likely.
This window typically spans the five days leading up to and including ovulation day. Why? Sperm can survive in the female reproductive tract for up to five days, however the egg is viable for about 12-24 hours after ovulation. So, having sex during this period increases the odds of sperm meeting an egg.
There are various methods to track your fertile window — from monitoring basal body temperature to observing changes in cervical mucus, and from ovulation predictor kits to smartphone apps.
Some common fertility misconceptions:
- Ovulation happens on day 14 of your menstrual cycle. No. Cycle length varies from person to person, as well as month to month
- Fertility is a women’s issue. Nope. About 40- 50% of infertility cases are due to male factors
- Using birth control for a long time can reduce your chances of pregnancy. Not correct. When contraceptive use is stopped, no matter the type or duration, it does not have a negative effect on the ability to conceive
- Certain sex positions improve the odds of pregnancy. Again, no. There is no evidence to support this claim
The menstrual cycle is an extraordinary process that plays a central role at the heart of human reproduction. Each phase is a choreographed dance of hormones and biological processes. Understanding that monthly dance can help us to make informed choices about our reproductive health.
Unlocking the benefits of Hera Fertility Starter Plan
If you’re looking to take control of your reproductive health, we can help. The Hera Fertility Starter Plan offers a comprehensive review of your fertility health. Whether you’re looking to start a family, preserve your fertility, or simply learn more about your fertility status, our team of fertility experts can help you get the answers you need.
The program includes a personalized intake appointment, medical history review, baseline fertility testing and, if necessary, fertility treatment options. Get in touch with our team to learn more, or get started with the Hera Fertility Starter Plan today.
