Your menstrual cycle and fertility – what your period can tell you (& the fertile signs to look for, each month)

Emma Harpham in partnership with Rita Health  |   10 Jul 2024

When it comes to understanding your menstrual cycle and fertility, there’s a lot of information out there. Getting to know what constitutes a normal cycle for you is really important, especially if and when you’re trying to conceive (TTC).

We’re all different, and it’s not always straightforward to work out what’s going on in our bodies. But to give you a starting point, we’re back partnering with the incredible team at Rita Health – the fertility assessment app that empowers people with ovaries with a holistic understanding of their fertility profile. Head to their website and tap ‘Start Now’ to learn more.

The assessment analyzes 102 factors that can potentially impact fertility – everything from your period to your medical history, and your mom’s menopause, to your sex life – and brings the power back to you, by turning fertility fears into curiosity and providing proactive information that helps you understand your body.

Take Rita’s holistic fertility assessment today, access your personalized report, and get clued up.

Now, over to their team for the menstrual cycle and fertility 101, including ways to work out your fertile signs, and how to spot other fertility-impacting factors that might come up each month. 

It all starts with your hormones

Let’s start by breaking down what’s actually happening in your body, and the hormones at play each month.

Your cycle starts with the follicular phase, where your pituitary gland releases follicle-stimulating hormone (FSH) to help eggs in your ovaries mature. Estrogen levels then rise, and your uterine lining begins to thicken. 

Around the middle of the cycle, a surge in luteinizing hormone (LH) triggers ovulation, releasing an egg from your ovary. In the luteal phase, progesterone increases to further help your uterus become receptive to an embryo, and potential pregnancy.

If no embryo implants, your estrogen and progesterone levels will drop again, kick-starting your monthly bleed.

What if I’m on hormonal birth control? 

First off, hormonal birth control doesn’t cause infertility. However, if taken for a long time, they can conceal underlying conditions making it seem like you have a symptom-free, regular cycle. 

Any bleeding on hormonal birth control is not a real menstrual period – it’s a regulated withdrawal bleed from hormone level drops. 

Allow 3 months for your menstrual cycle to get back to your ‘normal’, if and when you plan to conceive.

menstrual cycle and fertility calendar, showing a short menstrual cycle and fertility

What does your menstrual cycle say about your fertility?

What is a regular menstrual cycle?

A regular menstrual cycle is typically considered to be between 21 and 35 days in length, with a variation of no more than one week between cycles. 

Plus, ovulation usually occurs around day 11 for a 25-day cycle, day 14 for a 28-day cycle, and day 21 for a 35-day cycle. 

Keeping track of your cycle length and ovulation can help to understand your fertility and reproductive health better.

Short menstrual cycles and fertility

Having a short menstrual cycle, lasting less than 21 days, could indicate ovulation problems. 

You might not be releasing an egg regularly each month, which can impact fertility as without regular ovulation, it can be more challenging to conceive naturally.

Additionally, a short menstrual cycle may not provide enough time for the uterine lining to properly thicken, which is essential for the fertilized egg to implant and develop into a pregnancy. This shortened window can reduce the chances of successful conception. 

Chatting with your doctor to determine the underlying cause, and keeping tabs on the length and regularity of your menstrual cycle, is key here.

Long menstrual cycles and fertility

Having a menstrual cycle that’s longer than 35 days could mean that you’re having a long follicular phase. This may impact your fertility by delaying ovulation and reducing the frequency and regularity of ovulation. 

This could happen due to a hormonal imbalance, and uterine lining preparation for implantation can also be impacted. A longer menstrual cycle can make it more challenging to predict fertile days accurately and lead to difficulties in timing sex for conception.

Again, getting to the bottom of the underlying causes of your long menstrual cycle, and tracking potential ovulation days and cycle length, can help you if and when you’re trying to conceive.

Your menstrual cycle phases, symptoms, and potential fertility-impacting factors to look for

During your menstrual cycle, you’ll experience four main phases, each accompanied by various physical and emotional symptoms. 

Some of these symptoms might indicate potential underlying fertility-impacting factors. Here’s your at-a-glance guide, for an average 28-day cycle.

The menstrual phase  (Day 1 to day 5)

Physical symptoms – Bleeding, mild cramps, lower back pain, bloating, sore breasts, headaches, and fatigue.

Emotional symptoms – Mood swings and irritability may occur due to hormonal fluctuations.

Fertility-impacting factors to watch for – Keep an eye out for cramps, and their duration and timing. About 75% of women experience a degree of “normal” menstrual cramping, however severe menstrual cramps that prevent you from going about your day-to-day are not normal and could be a sign of an underlying issue. The length and intensity of your period are also important indicators of your reproductive health.

menstrual cycle and fertility

The follicular phase  (Day 1 to day 13)

Physical symptoms – As estrogen levels rise, women often feel more energetic and experience relief from menstrual pain. Some may also notice an increase in cervical mucus, which becomes clearer and more stretchy as ovulation approaches.

Emotional symptoms – Many women report feeling more positive and during this phase, as well as a gradual increase in libido.

Fertility-impacting factors to watch for – Try to get a feel for how your sex drive ebbs and flows. Sex drive is complex and lots of things can impact it, but there is a direct link between hormonal fluctuations and desire throughout your cycle, with your pre-ovulation estrogen peak causing it to increase, and your post-ovulation progesterone spike causing it to decrease. It is important to pay attention if your sex drive feels like it’s at unsatisfactory levels for too long.

The ovulatory phase  (Roughly day 14)

Physical symptoms – Some women experience mild pelvic pain (known as mittelschmerz), increased cervical mucus, and a heightened sense of smell, taste, or vision. Body temperature may slightly increase.

Emotional symptoms – Some women may feel a boost in energy and a sense of well-being. Libido often peaks during this time.

Fertility-impacting factors to watch for – Find a way to track your ovulation that works for you. As we’ve mentioned, estrogen peaks just before ovulation. This can cause your cervical mucus to change from creamy to stretchy and clear like raw egg whites, as well as your body temperature to increase slightly. More on this below.

Luteal phase  (Day 15 to day 28)

Physical symptoms – If conception doesn’t occur, symptoms like bloating, breast tenderness, swelling, headaches, and weight gain can appear. Acne flare-ups and constipation or diarrhea are also possible.

Emotional symptoms – This phase is notorious for PMS (premenstrual syndrome), which can include symptoms such as mood swings, anxiety, depression, irritability, and changes in appetite.

Fertility-impacting factors to watch for – Log the length of your luteal phase. A short luteal phase (meaning you get your period less than 10 days after ovulation) might not allow your uterine lining enough time to become receptive enough to support implantation, which is essential for pregnancy.

But how do I know when I’m fertile, exactly?

There are quite a few signs that can help you actually track your most fertile days (roughly 6 days for an average 28-day cycle) and work out when you’ve ovulated each month.

Tracking cervical mucus is one handy method; you’ll notice it becomes clear and stretchy, like egg whites, typically just before ovulation. 

Using LH test strips is another reliable way. A surge in LH typically indicates that ovulation will occur within the next 24 to 36 hours. 

Monitoring your basal body temperature (BBT) can also give you useful insights, as you’ll see a slight increase in your morning temperature right after ovulation. Some folks even use saliva fertility testing where ferning patterns appear under a microscope, to monitor their fertile window. 

By choosing one, or even combining these methods, you can get a pretty accurate picture of your fertile window over time.

how do I know when I’m fertile

5 easy changes you can make to support your menstrual cycle and fertility

We love a checklist. Here are the Rita Health team’s top tips for supporting your menstrual cycle and fertility, at home. 

  1. Track whether you ovulate. Ovulation is a very strong positive signal for your fertility health, and you can use any of the methods above.
  2. Learn when your mother went through menopause, if possible. If it was earlier than 45 years old, mention it to your doctor at your next annual OB/GYN appointment.
  3. Get tested for STIs. If you haven’t been in the last year, do it. Untreated chlamydia and gonorrhea can, in rare cases, lead to scarring and inflammation that adversely affects your reproductive organs.
  4. Minimize exposure to toxins. If you can, avoid being surrounded by products containing toxins and endocrine-disrupting chemicals (EDCs). EDCs can be found in pesticides, plastics, personal care products, cleaning supplies, and tobacco smoke.
  5. Keep moving, regularly. And don’t think that only heavy workouts count! Walking and stretching are also very valuable. Regular exercise has been shown to improve fertility health and the outcomes of fertility treatments at all ages. There is no ‘perfect’ exercise routine for fertility; however, moderate-intensity exercises like walking, swimming, or cycling for 30-60 minutes a few days a week are a great place to start. 

Read our wrap-up of how to improve fertility, with expert insight from the Rita Health team, for more useful pointers like these.

Learn more about your period health and how it impacts your fertility, as well as 80 other fertility factors that are within your control to change and improve. Take Rita’s holistic fertility assessment today, access your personalized report, and get clued up.

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