11 reasons why surprise pregnancies are a lot more common than you think

As much as the body is geared to revealing when we're pregnant, there are also factors which cause women to remain unaware of their pregnancy

'I didn't know I was pregnant until I gave birth' stories are often met with scepticism and disbelief rather than emotional support and empathy.

For while every pregnancy is different, our bodies are equipped to reveal signs we're expecting as early as two weeks.

But what if you were the one in 7225 women who remained unaware they were pregnant up until the moment they went into labour?

Given how our bodies seem to be geared towards telling us we're pregnant, surprise or cryptic pregnancies may require suspension of disbelief -yet they do happen, and Professional Education Advisor, Michelle Lyne from The Royal College of Midwives explains the reasons why.

1. Perimenopause

This is the period of a woman's life shortly before she goes through the menopause. It's a time when her hormones are in flux.

Decreasing levels of oestrogen in the body mean a woman is less likely to know she's pregnant.

A surprise pregnancy is particularly viable for younger women going through an early menopause (and therefore an earlier perimenopause.)

2. Denied pregnancies

Also known graviditatas ignota, this is a very strong influence of surprise pregnancies.

Because of where the sense of denial may stem from, it's also one which should be approached with sensitivity.

Among other factors, denied pregnancies may be a result of a woman's age, the state of the relationship she's in and how she feels about having a baby.

Some women are able to shut out the knowledge they are pregnant, and require emotional support, rather than disbelief or derision.

Not wanting to engage with the idea of being pregnant is a serious factor and deserves our empathy

3. False negative pregnancy test

A home pregnancy test needs to be administered at the right time, when there is the right level of human chorionic gonadotropin (hCG) present.

Produced in the placenta, hCG levels are also used to detect if a woman has miscarried.

While home pregnancy tests aren't infallible, a blood test done at your doctor's will be able to tell if you're pregnant.

4. Weight

In order to ovulate, women needs to be a certain weight.

Women who are clinically obese may have trouble ovulating and therefore may not be looking out for signs they've conceived. Obesity can make detecting pregnancy more difficult.

There is a definite relationship between weight and fertility

5. Irregular menstrual cycle

Missing a period is one of the key signs that a woman is pregnant. Normally, a period should manifest fourteen days after ovulation.

But having an irregular menstrual cycle makes it difficult to identify when a woman is ovulating and can mean she is used to not having a period - causing that symptom to be redundant.

For women who are planning on getting pregnant and take the contraceptive pill, it can between three to six months to self-regulate.

One of the first signs you're pregnant is missing a period - but what if you're used to that

6. 'Inactive babies'

This factor may tie in with denied pregnancies.

Unless something is wrong, babies do move. So it's more a case of not realising the baby is moving.

For women who didn't intend on getting pregnant, or are experiencing a denied pregnancy not picking up on a baby's movements - combined with other factors - this can mean they are not aware they are pregnant.

7. Breakthrough bleed

Happening at roughly the same time a period is due, this is in fact a sign of pregnancy which is mistaken for a period.

A breakthrough bleed happens when the embryo starts to embed in the uterine wall, and is usually a light bleed.

8. Complications in the uterus

A bicornuate or heart-shaped uterus is a uterus made up of two 'horns' separated by a septum - meaning the womb is effectively in two parts.

Pregnancy can occur on one side, and periods on the other, meaning unless a woman with a bicornuate uterus had been pregnant before, she might not suspect she is.

9. Endometriosis

Endometriosis is when tissue that looks and acts like endometrial tissue is found outside the uterus, usually inside the pelvic cavity.

It can lead to difficulties conceiving, and women who are affected by it who do get pregnant may miss the symptoms of being pregnant because of their endometriosis symptoms.

10. Mental health

Pregnancy can be a stressful time for women, and depending on what's going on in their lives, their minds may be preoccupied with other issues.

11. Sickness

For women who have experienced a serious illness, and have a pathological fear of that illness coming back, they may associate symptoms such as morning sickness with relapsing.