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What does a infertile period look like?

An infertile period, also known as the infertile window, refers to the specific days in a woman’s menstrual cycle when she is least likely to get pregnant. This is the opposite of the fertile window, when a woman has the highest chances of conception. Knowing when the infertile period occurs can help couples who are trying to avoid pregnancy time sex accordingly. Read on to learn more about what an infertile period typically looks like.

When does the infertile period occur?

A woman’s menstrual cycle is usually around 28 days long, although it can range from 21 to 35 days. Ovulation, when an egg is released from the ovaries, generally occurs around day 14 of the cycle but can happen anywhere between days 11 and 21. The infertile period corresponds to the days right before and after a woman’s period, when conception is extremely unlikely.

More specifically, the infertile days are:

  • During menstruation
  • For around 5 days after your period ends
  • The couple days before your next period is due to start

So in a 28-day cycle where ovulation happens on day 14, the infertile days would be:

  • Days 1-5 of your cycle (during your period)
  • Days 26-28 of your cycle (before your next period)

The fertile window, on the other hand, spans from around 5 days before ovulation up until a day after. This is when conception chances are highest if you have unprotected sex.

Why these days are unlikely for conception

There are several biological reasons why getting pregnant is extremely difficult to impossible during the infertile period:

  • Menstruation – Sperm cannot reach an egg when there is menstrual flow present. The uterus is shedding its lining which blocks and flushes out sperm.
  • After menstruation – For around 5 days after your period ends, there is no egg present for sperm to fertilize. Ovulation has not occurred yet in the cycle.
  • Before your next period – At the end of your cycle, your egg has already been released from the ovary and is no longer viable. Fertilization cannot happen.

Essentially, during these infertile days, conception is impossible because either no egg is available yet for fertilization or the egg has already passed through the fallopian tubes. The uterus is also not prepared for implantation outside of the fertile window.

How can you identify the infertile period?

Tracking your menstrual cycles is the best way to figure out when your infertile days likely fall each month. Here are some tips:

  • Use a calendar to mark when you get your period for several months. This will help you identify your cycle length.
  • Assume ovulation happens around 14 days before your next expected period if you have a 28-day cycle. For other cycle lengths, ovulation typically occurs about two weeks before your period is due.
  • Mark your likely ovulation day on the calendar. The infertile period will be the 5 days of bleeding/spotting during your period as well as the days right before your next expected period.
  • You can also use ovulation prediction kits and fertility tracking methods like basal body temperature to pinpoint ovulation and the fertile window each month.

Signs of the infertile period

In addition to tracking your cycle, there are some signs that suggest you’re in your infertile period:

  • Bleeding/spotting – Menstrual flow indicates you are on your period and not fertile. Normal blood flow ranges from light to heavy.
  • Dry cervical mucus – Just after your period and right before your next one, cervical mucus is usually sparse, thick and sticky. This does not promote sperm mobility.
  • Lower basal body temperature – Your basal body temperature drops before ovulation and rises after. A higher temp suggests you’ve already ovulated.
  • Negative ovulation test – If an over-the-counter ovulation test shows a negative result, your luteinizing hormone surge has not occurred yet and you have not ovulated.

What does cervical mucus look like?

Observing your cervical mucus pattern throughout your cycle can help identify when you are most fertile. Here’s what to look for:

  • Menstrual period – Little to no mucus present
  • After period – Cloudy, sticky, gummy mucus. Not sperm-friendly.
  • Approaching ovulation – Wetter, more slippery mucus that feels similar to egg whites. This supports sperm survival.
  • Ovulation – Abundant, clear, slippery egg white-like mucus
  • After ovulation – Returns to being sticky, cloudy and sparse
  • Before next period – Dry mucus

During the infertile time frame, you will observe little to no cervical mucus present or it will be thick, sparse and infertile quality.

Does cycle length affect the infertile days?

Yes, your cycle length impacts when your fertile and infertile days occur each month. Here’s how:

Shorter cycles

If your cycles are shorter than 28 days, say 21-24 days, ovulation happens earlier. This means your infertile window before your period also starts sooner.

For example, in a 24-day cycle where you ovulate on day 10, the infertile days may be:

  • Days 1-5 (period)
  • Days 22-24

Longer cycles

In longer cycles of 30 days or more, ovulation is delayed until around day 16 or later. This causes the infertile period before your next period to be longer.

In a 32-day cycle with ovulation on day 18, the infertile days may be:

  • Days 1-5 (period)
  • Days 28-32

Irregular cycles make it harder to predict the infertile days, so cycle tracking is especially important.

Does breastfeeding impact infertility?

Yes, breastfeeding can affect the return of fertility after giving birth. Here’s how:

  • Exclusive breastfeeding can delay ovulation and periods for up to 6 months or more.
  • During this time, the infertile days are hard to predict since menstruation has not resumed.
  • As you start supplementing with formula or solid foods, fertility can return even if breastfeeding continues.
  • Once menstrual cycles regulate, the normal infertile days will apply.

So breastfeeding might extend the infertile period, but you can still get pregnant before you get your first postpartum period. Use contraception or abstain as desired.

Infertile period in perimenopause and menopause

As women approach menopause, cycle irregularities make fertility hard to predict. Here’s what to know:

  • Periods may get closer together, farther apart, lighter or heavier.
  • Ovulation becomes inconsistent and may cease months or years before periods stop.
  • Hormone levels fluctuate, so fertility signs are unreliable.
  • Infertile days are uncertain until menstruation has ceased for 12 consecutive months (menopause).

Until reaching menopause, consider yourself potentially fertile even if cycles are irregular. Track ovulation signs if actively trying to conceive or avoid pregnancy.

Ways to prevent pregnancy during the infertile period

Even though the chances of conception are extremely low during the infertile days, you may still wish to use contraception:

  • Use condoms or avoid sex during menstruation if you dislike period sex.
  • Use condoms for 5 days after your period as an added precaution.
  • Abstain or use condoms when approaching your expected next period.
  • Consider emergency contraception if you’ve had unprotected sex right before your period and want to prevent pregnancy.

Remember that sperm can sometimes survive up to 5 days in the female reproductive tract. So consider yourself potentially fertile until you confirm ovulation happened using fertility tracking methods.

When to see a doctor

See your doctor if:

  • Your periods suddenly stop for 3 months and pregnancy has been ruled out.
  • You’re under 45 and have missed periods for 4-6 months without pregnancy.
  • Your cycles are shorter than 21 days or longer than 35 days.
  • You experience heavy/prolonged bleeding during your period.
  • You have severe menstrual cramping and pain.

Abnormal cycles may indicate hormonal imbalances, uterine fibroids, endometriosis or other medical conditions requiring treatment.


The infertile period refers to the days at the start and end of a woman’s menstrual cycle when conception is extremely unlikely. This coincides with menstruation and the days right before your next period is due. Tracking your cycles helps identify the infertile window each month. Avoiding sex or using contraception during these days can prevent unwanted pregnancy for couples. However, unprotected sex before or after the infertile period still carries a significant risk of conception occurring.