MENSTRUAL CYCLE BASICS

Back to basics: Understanding your menstrual cycle. What is “normal” anyways?

 

Growing attention is being paid to the menstrual cycle in wellness circles, doctor’s offices and even academic research. With more and more women developing an interest and awareness around their own cycle and symptoms, many looking for answers and understanding for more specific concerns or symptoms. “Is this normal?”

It is both an amazing and overwhelming time to be searching for those answers with social media providing some good and some (mostly) bad answers. There’s a big push to “heal your hormones”… but what does that really mean? To really dive into how we support your symptoms and regulate your cycles, we need a quick science lesson!

 

How the menstrual cycle works

The menstrual cycle occurs through the amazingly integrated actions of our brain - the hypothalamus and pituitary - our ovaries, and our uterine endometrium. Hormones released from both the brain and ovaries work through feedback and communication with each other to control the cyclical nature of our periods.

 

A part of our brain called the hypothalamus monitors our environment, nutritional status, exercise, stress, and even emotional state, to alter the our hormonal secretion from the brain. The hypothalamus releases a hormone called GnRH in pulses, which signals our pituitary gland (also in the brain!) to release hormones. We sometimes refer to these hormones as the “upstairs hormones” - referring to follicle stimulating hormone (FSH) and luteinizing hormone (LH). They send signals to the ovaries to release the “downstairs hormones” – estrogen and progesterone.

 

The menstrual cycle has two distinct phases, the follicular and luteal phases, separated by one event - ovulation.

 

Follicular phase:

The follicular phase starts on day 1 of your period – the first day of bleeding. Hormones are low at the beginning of your cycle. This is sensed by the brain, which compensates by releasing more FSH and LH. FSH stimulates the growth of a few follicles in the ovary - not just one! These follicles secrete estrogen and whichever grows the quickest and secretes the most estrogen becomes the “dominant follicle”. This increase in estrogen tells the brain to stop releasing so much FSH and we are left with one dominant follicle that continues to mature.

 

Most (but not all) of the variation of your cycle length comes from changes in this phase. The follicular phase is often called the proliferative phase because a primary purpose of this phase is to grow the endometrium (where an embryo would attach) of the uterus. Estrogen stimulates this growth by increasing cellular and glandular tissue, as well as increasing the depth of arteries that supply the endometrium.

 

Estrogen also helps create a sperm-friendly environment in the days leading up to ovulation. At this point in the cycle, mucous from the cervix (cervical mucous) will be more abundant, watery and elastic - think, egg-white consistency. This helps sperm travel through the cervix.

 

At the end of the follicular phase, estrogen levels are are quite high! As estrogen rises to a threshold level, this sends signals back to the brain to release more LH. LH rises rapidly - this is what we call the “LH surge” which happens about 36-44 hours before ovulation. With this surge of LH, the mature follicle breaks and an egg is released. This is ovulation.

 

The luteal phase:

Ovulation marks the start of the second phase - the luteal phase. This phase varies less (but still an vary!) - and is usually about 14 days from ovulation to the next period. Those high levels of LH from the “surge” stimulate progesterone to rise. Progesterone prepares the endometrium for the possibility of a fertilized egg. Preparation of the endometrium means increasing blood supply and stimulating more mucous secretions. The endometrium stops growing in thickness, but gets more complex! We need to be able to deliver energy to the embryo when it implants, so the cells of the endometrium start storing more sugar. Progesterone also changes the structure of the arteries – what we call spiral arteries - in order to provide more surface area for nutrient delivery.

 

The high levels of progesterone also increase our temperature set-point (controlled by the hypothalamus). If you were to track your temperature in the morning every day of your cycle, you would see a slight rise after ovulation that lasts for several days after.

 

As the end of this phase is reached, hormones are mostly secreted from the corpus luteum – the leftover follicle where an egg was released from the ovary. If no pregnancy occurs, this corpus lutes regresses and levels of estrogen and progesterone drop rapidly! This rapid drop is what signals the shedding of the endometrium (menses, or your “period”) but also part of what we think contributes to classic premenstrual syndrome (PMS) symptoms.

 

What’s normal?

Your period is the shedding of that endometrial layer that can’t be maintained without those hormones. Menstrual blood is mostly arterial blood - which is why it often starts off bright red - but also has some venous blood, tissue debris, immune cells etc. In regular flow, our body has great systems to break up blood clots quite well. In very heavy bleeding, you may see more clots. This is something to chat with your provider about.

Understanding what is normal vs. abnormal helps us gather information of what might going, or what might actually be just regular variation of a health cycle. Some things to look out for to understand a healthy cycle are:

Key features of a normal cycle

How long you bleed for

  • Periods typically last between 3-5 days on average (but can be as long as 8 days)

How much you bleed

  • Normal blood loss can ranging from spotting to 80 mL.

    • When blood loss is above 80mL we are more concerned.

      • But what does 80mL even look like? Unless you use a cup or disc as your menstrual product, measuring probably isn’t realistic.

      • We usually say if you are having to change a pad, tampon or cup more than once every couple of hours, we should talk.

      • Various factors can impact volume of blood flow and what is considered “normal” including bleeding/clotting disorders, hormonal causes, physical causes (like fibroids), immune conditions etc.)

Pain & Symptoms

  • Normal cycles should not require absences from work, activities of daily life or large quantities of painkillers.

  • Pain

    • Your period should not be too painful. If you are popping the maximum (or more) advil dose just to get through your day…that’s too much pain and you deserve an investigation.

  • Mood disturbances

    • If you are experiencing severe mood swings that are impacting your ability to work, get along with others or not having feeling your best, there are solutions for you.

  • Physical symptoms of PMS

    • Feeling bloated, breast tenderness, headaches, and all the other lovely symptoms of PMS? There are things we can do to support you.

Length of Cycle

  • Cycles should be between 23-35 days in length (from the start of your period, to the start of your next period)

    • Any longer or shorter and we should investigate why this is. Changes in cycle length could be caused by:

      • Energy deficits – under-eating or over-exercising

      • High stress

      • Polycystic Ovarian Syndrome (PCOS)

      • Thyroid conditions

      • Maturity of the brain to ovary connection - in the few years after puberty!

      • Perimenopause

 Curious about what’s normal in your own cycle or want to chat about some symptoms you are having? You can book in with one of our Naturopathic Doctors.

hormonal health, Pelvic HealthCrafted Balance Clinic