If you don’t get pregnant, you’ll bleed every 28 days or so, and that’s pretty much all there is to the menstrual cycle, right?
Well, that might be the basics of the menstrual cycle, but it’s really broken into four distinct phases.
Understanding each phase of the menstrual cycle, and what is or isn’t normal in each phase, can be an important part of your reproductive and overall health.
Whether you’re trying to conceive, trying to avoid pregnancy, or simply not feeling your best, understanding your menstrual cycle can be vital.
The better you understand your menstrual cycle, the sooner you might notice any reproductive health issues. You will also be more likely to achieve a desired pregnancy, and better able to make an informed decision regarding contraception.
What Are The Phases Of The Menstrual Cycle?
There are four distinct phases in the menstrual cycle:
- Follicular Phase
- Luteal Phase
It’s important to understand each phase – when it occurs, how long it lasts, and what symptoms might warrant a medical evaluation. It’s all part of understanding your reproductive health.
Menstruation – What Is It And What Is Normal?
Menstruation is when you’re actively shedding your uterine lining. A drop in the hormone progesterone triggers your uterine lining to be shed. This is when you experience vaginal bleeding. This phase typically lasts 3-5 days. Less than 3 days or longer than 5 might indicate a reproductive health issue, which should be evaluated. It could also be your ‘normal’.
The first day of spotting and bleeding is considered day one of your cycle. When you fill out a medical questionnaire or discuss your current health at appointments, you’re likely to be asked the date of your last menstrual period (LMP). This is the first day of your last period, or cycle day one.
During menstruation your bleeding and discharge include:
- An average of 30-50ml of blood
- Cervical mucus
- Endometrial cells
- Vaginal secretions
The combination of things can make it seem as though you’re losing a large volume of blood, but it’s rare to lose more than 60-80ml (considered heavy bleeding).
You only need to be concerned about menstruation when:
- You soak through pads or tampons at a faster rate than one per hour, for more than an hour or two
- Cramping interferes with your ability to work, go to school, or socialise
- Menstrual bleeding lasts longer than a week
- Spotting occurs for more than 3 days prior to and/or 3 days following regular menstruation
Often we are told period pain is normal, but it isn’t really normal. Common, yes, but normal, no. It’s also important to know that a significant portion of women with endometriosis are asymptomatic (i.e. have no symptoms).
See our article about 7 loving things to do for yourself when you have your period (or just before!).
The Follicular Phase – What Happens After Menstruation
Once menstruation ceases, your body begins to prepare for another potential pregnancy. The luteinizing hormone (LH) is released by the pituitary gland, which triggers several follicles (cells holding immature eggs) to develop in the ovaries.
The development of follicles also triggers the release of the hormone estrogen which causes the uterine lining to thicken in preparation for possible implantation of a fertilised egg.
Typically, just one egg matures and moves towards the ovary’s surface in preparation for ovulation. Sometimes more than one egg is released which results in fraternal twins, triplets, etc. This is especially common when fertility treatments are used. The rest of the follicles, which didn’t fully mature, are reabsorbed.
The follicular phase can vary quite a bit. It begins when menstruation starts and ends when ovulation occurs.
Ovulation – Your Fertile Period
You’re at peak fertility during ovulation.
The rising estrogen released during the follicular phase eventually triggers the release of gonadotropin-releasing hormone (GnRH) which then triggers a peak LH surge. This LH surge triggers the release of your mature egg (or eggs).
The LH surge causes the egg to be released from the ovary and begin its journey down the fallopian tube towards the uterus. The egg is released about 12-36 hours after the LH surge.
You can read more about ovulation symptoms in the BellyBelly article Ovulation Symptoms – 10 Symptoms Of Ovulation.
It’s also important to note that ovulation pain isn’t normal. Some sort of sensation is normal, but if you’re experiencing actual pain during ovulation, it could be indicative of reproductive health issues.
Once an egg is released it can be fertilised within 6-24 hours. If it isn’t fertilised in 24 hours, the egg will die.
As for the sperm, an outdated belief is that sperm can last for days inside a woman’s body, however what we know now is most sperm are dead within an hour of ejaculation. There will only be about 10-20 single sperm left to make it to the woman’s fallopian tubes and only about 2-5 sperm left to fertilise the egg.
You might like to read 8 Facts About Sperm That You Wont Find On Wikipedia.
On average, women will begin their period 14 days following ovulation. Anywhere from 9 to 18 days, however, is within the normal range. If you begin a period less than 9 days after ovulation it could be indicative of reproductive health issues.
The ‘two-week wait’ is a phrase commonly used in forums for women trying to conceive. After ovulation, many women count down the two weeks until their expected period, in the hopes it won’t begin. However, this can be inaccurate, especially for women who are not undergoing an IVF cycle. This is because after ovulation, it takes around five days for the blastocyst to form, then two more days for implantation. Only then can you receive a positive result from a pregancy test. So really, it can be more like a three week wait for women who aren’t using assisted reproductive medicine.
During the luteal phase, the released egg is known as the corpus luteum. The corpus luteum ensures estrogen continues to rise, as well as progesterone, to help the uterine lining thicken in preparation for implantation.
If fertilisation doesn’t occur, eventually the corpus luteum breaks down, and estrogen and progesterone levels drop. The drop in progesterone triggers the start of menstruation. If fertilisation does occur, the egg might implant which indicates conception and a developing pregnancy.
Around 50% of fertilised eggs don’t implant properly. This isn’t usually indicative of any problems, but rather a normal process to ensure only properly fertilised and healthy eggs are implanted. Timing intercourse with ovulation, and the failure of fertilised eggs to implant, partly explain why it’s completely normal for it to take 6-12 cycles to achieve a pregnancy.
In each cycle, there’s around a 20% chance of pregnancy occurring.
Reproductive specialist Doctor Andrew Orr recommends women don’t get too hung up on the luteal phase. “A patient of my clinic became pregnant after she ovulated as late as day 26 in her cycle. We knew it was accurate, because her partner is a FIFO (fly in, fly out) worker. A paper in the British Medical Journal says that statistically, ovulation is more likely to occur between days 18-28. There is 10% probability of being in your fertile window during days 10-16, which is commonly known as the fertile window. Around 70% of women are fertile outside of these times. There’s even a 1-6% chance of being fertile during your menstrual cycle!”
How Long Is The Entire Menstrual Cycle?
The average cycle is around 28 days long. However, anything within the 21-35 day range can be normal. The length of the follicular phase can vary quite a bit and still be normal. The luteal phase, however, is the phase where length can be indicative of problems.
Tracking your menstrual cycle can help you notice any changes in your cycle, and help you catch the short luteal phase, which could be problematic if you’re actively trying to conceive.
If you experience heavy bleeding, painful cramping, or painful ovulation, it’s a good idea to get a referal to a women’s health specialist or gynaecologist, who will either diagnose or rule out any reproductive health issues.