Cryptic pregnancy - when you don't know you're pregnant

No, these aren't rubbish, woefully unfunny jokes, they're true stories. And as it turns out, being pregnant and not having the faintest clue is a very real condition.

Cryptic pregnancy is more common than you think

As bizarre as it sounds, cryptic pregnancy (or 'denied pregnancy' if you're in the US) is a very real phenomenon. Some women do become pregnant and are genuinely unaware they're expecting until several months into their pregnancies - or more shockingly - when they go into labour.

It's not just something made up by the tabloids to sell newspapers. It might not be the norm and it's got some experts unconvinced, but there are some genuine cases.

Take Katie Price. She's known as a bit of an expert when it comes to being pregnant but she was shocked to discover in the spring of 2014 that she was 6 months pregnant again just 8 months after giving birth to her daughter Jett. 'I had some really bad stomach pains,' she explains. 'I didn't feel pregnant, though.” After returning home from a holiday, she took a test and discovered the surprising news.

And just recently, 28-year-old Kiwi Charlene Wells gave birth to a healthy baby boy, less than 15 hours after finding out she was pregnant.

But how could you not know?

Charlene had never felt her baby kick because her placenta was in an unusual spot, so when she started experiencing severe abdominal pain and went to hospital, a pregnancy test quickly revealed she was 40-weeks pregnant.

"I was pretty shocked. I thought it was kidney stones or something," the surprised new mum said in perhaps the understatement of the year.

And sometimes you know, but the pregnancy test says No

This is the most common form of cryptic pregnancy - when your instinct tells you you're pregnant but pregnancy tests disagree, even when you're 3 months pregnant.

Don't take our word for it. It's happened to MFMers...

Allison Jones was trying for a baby and had taken numerous pregnancy tests which had all been negative. "I finally got my BFP [Big Fat Positive - on a pregnancy test] at 15 weeks!!! I am almost 16 weeks," she says on our forum. "Finally got a positive home urine test! I knew I was pregnant, had many symptoms but all BFN [Big Fat Negative] until today!"

Star75, a 40-year-old mum of 4, says, "With my second pregnancy, I didn't get a positive result until I was 3 months pregnant - but all the others showed up quickly.'

Haider Jan, Consultant Gynaecologist and Obstetrician at Dr Morton's (an online UK-based medical helpline), knows a lot more about the phenomenon. "Recent studies suggest that cryptic pregnancy may be much more common than previously thought with some estimates amounting to nearly 1 in 475 pregnancies."

Haider continues, "There is a fine line between a cryptic pregnancy, when the woman simply doesn’t show any symptoms and indeed may even continue to have a monthly bleed, and a concealed pregnancy, when the woman subconsciously suppresses any idea that she may be pregnant, and can even come into the A and E department with abdominal pain and give birth hours later. Quite a shock!"

Yet despite the evidence, not everyone's a believer

When we went to birth charity Tommy's to ask for their views on cryptic pregnancy, one of their midwives felt that "more often than not it happens in soap story lines rather than real life".

So why might you not realise you're pregnant?

1 Pregnancy tests can be negative

As a general rule, home pregnancy tests are the best way of finding out if you are pregnant. However, in some rare cases, you may be pregnant, but not have enough HCG in your system - which means you won't get a positive reading.

HCG or human Chorionic Gonadotropin, is the hormone that your baby produces when you're pregnant and is the key to your home pregnancy test giving a positive reading.

In a nutshell, HCG is produced by the placenta and is secreted into the lining of the uterus, where it eventually enters your bloodstream and exits your body through urine.

If your baby isn’t producing enough HCG then you will get a false negative. It's rare but it does happen.

2 You still have periods

It is still possible to have ‘periods’ if you are pregnant. They might not be quite the same as your normal cycle but you might not necessarily pick up on the change especially if you're used to irregular periods or varying blood flow.

3 Pregnancy symptoms may be masked by a hormone imbalance

Hormones are so key in pregnancy, but the following conditions may upset your normal hormone levels:

• Polycystic Ovarian Syndrome (PCOS)
• Perimenopause
• Recently having given birth
• Breastfeeding
• Low body fat ratio
• Obesity
• Using birth control particularly the injections or coil

This doesn't mean there's anything wrong with your baby

You shouldn't be panicked once you eventually get a positive reading, the low reading could be that cryptic babies do develop at a slower pace and it’s not uncommon for a baby to be born much later than the 40 weeks stage. But there's no reason for this to have any negative affects.

What do you do if you think you're pregnant but the test is negative?

First, look out for symptoms. They're your best indicator after a test that you are pregnant:

• Sickness or nausea
• Severe tiredness
• Frequently needing to pee
• Loss of appetite
• Increased hunger
• Back pain
• Heart burn
• Funny taste in the mouth
• Stomach pains
• Headaches
• Tell me more about early signs of pregnancy

Do another pregnancy test and if it's still negative, talk to your GP. Your doctor can arrange for a blood test and can talk you through your symptoms.

Read more:

• "Something just dropped out of me" - woman gives birth on a plane unaware she was pregnant
• "I thought I was bloated" - woman finds out she's 8 months pregnant when baby kicked at gig
• Weight gain in pregnancy - what to expect