Many women assume that their period is an ‘infertile’ phase during which it is impossible to get pregnant. However, that is not always the case. The menstrual cycle is not a fixed, perfectly predictable clock; it is a dynamic hormonal system that can vary from month to month. As a result, bleeding can be misleading, and your fertile window may sometimes fall differently than you think.

Why it is still possible to get pregnant during your period

To understand why it is possible to get pregnant during bleeding, you need to know how your cycle works. You can only get pregnant if ovulation has occurred and there are sperm present that can fertilize an egg. Sperm can survive in the body for up to five days. This means that sex during bleeding, even if you think it is your period, can lead to fertilization if you ovulate shortly thereafter.

Women who are especially likely to get pregnant during their period are those with:

• a short cycle (e.g. 21–25 days)

• early ovulation (day 8–11)

• bleeding that is not a real period

have a higher risk of getting pregnant during their period.

So it is not the bleeding itself that makes you fertile, but the time when you ovulate and whether sperm is present long enough to meet the egg.

Not every period is a menstruation

Many women rely on bleeding as a sign that their cycle is starting again. However, there are several types of bleeding that resemble menstruation while biologically meaning something else. This bleeding can occur before, during, or after ovulation, which means your fertile window may be very different from what you think.

Implantation bleeding

Short-lived, light bleeding around 6–12 days after ovulation. By then, you are already pregnant. This bleeding is often mistaken for an early period, so women do not realise that they are already carrying a fertilised egg.

Ovulation bleeding

Light pink or red bleeding around ovulation. This happens due to a slight drop in oestrogen and is completely normal. The problem: many women think they are menstruating, when in fact they are extremely fertile.

Breakthrough bleeding

Occurs when hormones fluctuate, for example after stopping contraception, due to stress, irregular follicle maturation, or a disruption in the oestrogen/progesterone balance. The bleeding resembles a light period, but has nothing to do with a new cycle.

Hormonal adjustment bleeding

When you start with proper support, such as folate, choline, magnesium and Omega 3 DHA, your cycle may temporarily shift. Many women are alarmed by this, but it is often a positive sign: your hormones are beginning to stabilise.

Bleeding therefore does not always indicate that your cycle is starting again. This is precisely why women can be surprised by a pregnancy, even though they thought they were “menstruating.”

How your cycle works

A menstrual cycle consists of two main parts:

1. Follicular phase (from menstruation to ovulation)

This is when eggs grow and mature. The length of this phase can vary greatly between women and even from month to month. Ovulation can occur early or late depending on:

• stress
• nutrition
• sleep deprivation
• illness
• thyroid function
• hormonal imbalances

This makes the follicular phase the most variable phase of the cycle.

2. Luteal phase (from ovulation to menstruation)

This phase is much more stable and lasts 10–14 days for most women. A luteal phase that is too short makes implantation more difficult.

A shift in the follicular phase, for example if ovulation occurs 3–5 days earlier or later, can make your cycle look completely different. This explains why some women think they are fertile during their period: ovulation simply occurs sooner than expected.

What a short, long or irregular cycle means for your fertility

Your cycle length does not tell you whether or not you can get pregnant, but it does provide information about how your hormones work together.

Short cycle (24–26 days or shorter)

A short cycle often means early ovulation.
This can be positive or negative:

✔ you ovulate regularly
✔ you have many chances each year
✘ but your fertile window falls earlier than you think
✘ the luteal phase may sometimes be too short for successful implantation

Women with a short cycle can absolutely get pregnant; they just need to pay attention to their fertile days earlier in the month.

Long cycle (35+ days)

A long cycle usually means that ovulation occurs later.
Causes may include:

• recovery after contraception
• stress
• PCOS-like symptoms
• thyroid problems
• hormonal fluctuations

Getting pregnant is still possible as long as ovulation occurs. The downside: you have fewer ovulations each year and more uncertainty about your fertile days.

Irregular cycle (sometimes short, sometimes long)

An irregular cycle usually means that your body is struggling to create a stable ovulation time.

This can be due to:

• stress
• interrupted sleep
• weight fluctuations
• nutrient deficiencies
• hormonal recovery after contraception

An irregular cycle does not mean that you are infertile — but it does mean that timing becomes more important.

A regular cycle is no guarantee of getting pregnant quickly

Many women think that a regular cycle (for example, every 28 days) automatically means that everything is working perfectly hormonally.
But regularity only tells you one thing:

Your ovulation occurs at approximately the same time.

It says nothing about:

• the quality of the egg
• the quality of ovulation
• your progesterone after ovulation
• how well your body can sustain a pregnancy
• inflammation levels
• thyroid function
• nutritional status
• stress levels

This is why women with a “perfect 28-day cycle” can still have difficulty getting pregnant.

Regularity is good, but it is no guarantee.

Good vitamins and minerals affect your menstrual cycle 

When women start taking effective support such as:

• folate
• choline
• DHA
• magnesium
• B vitamins
• vitamin D
• iodine

the cycle may change in the first few months.

This is usually a sign that:

✔ your hormones are coming into balance
✔ your ovulation is becoming more consistent
✔ your luteal phase is becoming more stable
✔ your cycle is finding a healthier rhythm

The body responds to nutrition and support, and that response can mean it is preparing for a better chance of pregnancy. If you have not previously taken bioavailable vitamins and minerals, your body may react after you start taking good vitamins. This may become apparent after just one week through, for example: light bleeding halfway through your cycle, a shorter or longer cycle than usual, or no menstrual symptoms like you are used to. 

This is all a positive sign and shows that your body is responding to the bioavailable vitamins and minerals. Your hormones are recovering. This first manifests as an ‘abnormality’ compared to what you are used to, after which your body and hormones will become more balanced. 

Do you want to get pregnant? Then make sure you get to know your body, that you get to know your menstrual cycle, and make sure your body + hormones get the support they need, namely:

• Healthy and varied nutrition
• The right preconception supplements with bioavailable vitamins and minerals
• A healthy lifestyle with enough exercise and rest. 

Frequently asked questions about wanting a child

1. How do I know if I have ovulated if my cycle is different than usual?

Look for signs such as changes in cervical mucus, a rise in your basal temperature, and an LH surge. An irregular cycle does not mean that you do not ovulate — only that it is harder to predict.

2. Can I get pregnant if my cycle is different every month?

Yes. As long as ovulation occurs, you can get pregnant. An irregular cycle may only mean that your hormones need extra support to become more regular.

3. What does spotting between my periods mean for my fertility?

Spotting does not have to be a bad thing. It is often caused by hormonal fluctuations around ovulation or by a shorter luteal phase. If it happens regularly, cycle support can help.

4. Is a short cycle (25 days or shorter) bad for getting pregnant?

Not always. Many women with a short cycle simply get pregnant. The most important thing is that your luteal phase is long enough (10–14 days) and that your ovulation occurs properly.

5. Is a long cycle (35+ days) a problem for my fertility?

A long cycle often means that ovulation occurs late. This can make it harder to find your fertile days, but you can still get pregnant if ovulation occurs.

6. Can bleeding after my ovulation mean that I am pregnant after all?

Yes. Light bleeding around 6–12 days after ovulation can be implantation bleeding. This is not menstruation and may actually indicate an early pregnancy.

7. Can stopping contraception make my cycle irregular?

Yes, that is normal. Your body needs time to restore its natural hormonal cycle. This can take 1–6 months, without permanently affecting your fertility.

8. Can you be pregnant while you think you are menstruating?

Yes. Some bleeding resembles menstruation but is not — such as implantation bleeding, breakthrough bleeding, or ovulation bleeding. As a result, you can be pregnant without realising it.

9. Is a “nice regular cycle” a guarantee that you will get pregnant quickly?

No. A regular cycle only means that your ovulation is predictable. It says nothing about the quality of ovulation or your hormonal balance. Regularity is an advantage, but no guarantee.

10. Can vitamins change my cycle?

Yes. When you start taking proper support such as folate, choline, magnesium, and DHA, your cycle may temporarily change. This is often a positive thing: your hormones come into balance and your cycle normalises.