Cryptic Pregnancy: Pregnant without knowing
It might be hard to believe, but some women only realise they're pregnant when they give birth. Our expert GP explains everything you need to know about cryptic pregnancies and who is most at risk.
Imagine growing a baby inside you for 9 months and only realising you were pregnant when you went into labour or the baby actually came out. It might sound like something from a film or novel but for around 325 women in the UK each year this is a reality – and it's called a cryptic pregnancy.
So how can a woman not notice a growing bump, a baby kicking or morning sickness and how common is it to not realise you're pregnant until late on in the pregnancy? We asked Dr Philippa Kaye, MadeForMums' resident GP, to explain this fascinating occurrence – why it happens, what the complications can be and who might be most at risk.
What is a cryptic pregnancy?
"A cryptic pregnancy, also sometimes called a hidden pregnancy, is when a person is not aware that they are pregnant until late in the pregnancy, or even up until labour and delivery," says Dr Philippa. "It isn’t particularly common, though perhaps not as rare as you may think, estimates suggest 1 in 2500 pregnancies are hidden for a period of time. Most people find out they are pregnant in the first trimester, somewhere between 4 and 12 weeks of pregnancy, in a cryptic pregnancy this is much later."
What causes a cryptic pregnancy?
"A cryptic pregnancy can happen due to a variety of reasons," says Dr Philippa. "For example if you have a false negative pregnancy test and so don’t realise you are pregnant for a period of time. Or if you normally have irregular or even absent periods (if this is the case please see your GP), you may not notice a change. This might particularly occur due to PCOS, or perimenopause.
"Sometimes women will still have bleeds during pregnancy and so may assume that their periods are continuing and that they aren’t pregnant. Some women will have very few or mild/minor symptoms, or may not notice changes in their bodies, for example if they have obesity and so may have a hidden pregnancy. Other women may be relying on contraception, which may fail, or for example a coil might fall out. In other situations stress plays a role.
"In addition if the placenta is anterior, meaning it is in a forward position it can be harder to feel the movements of the developing foetus, which aren’t generally felt until the second half of pregnancy."
What are the signs and symptoms of a cryptic pregnancy?
"The point is that there may not be signs or symptoms of a cryptic pregnancy, it is hidden!" says Dr Philippa.
How long can a cryptic pregnancy last?
"Some women will report that they weren’t aware of the pregnancy for the full nine months, until labour, and others who have less painful labours even up until the moment of delivery. In other women they may only notice during the later stages of pregnancy, and others much earlier on."
Are there any risks or complications associated with a cryptic pregnancy?
"The main issue around cryptic pregnancies is that you may not present for antenatal care, including tests for both you and the baby. If you are planning to have a termination of pregnancy, if you find out you are pregnant very late this may not be possible. In addition to this there is a psychological burden of finding out later meaning that you have less time to prepare for delivery."
What medical assistance do you need for a cryptic pregnancy?
In a cryptic/hidden pregnancy you are not aware you are pregnant, so women don’t ask for help, support and assistance. If you do find out you are pregnant at a later stage please do seek medical advice.
Real life story: Bryony's Surprise Birth at Work
If you think it's impossible not to know you're pregnant until you give birth then this story reported by the BBC in April 2025 about Bryony Mills Evans' cryptic pregnancy might change your mind.Bryony Mills-Evans had no idea she was pregnant until she gave birth alone, on a treatment bed, at the beauty salon where she worked. Believing she was experiencing menstrual cramps, Bryony went to lie down. Within ten minutes, she had delivered her 6lb 14oz daughter, Willow.
Without access to a phone she instinctively cut the umbilical cord using eyebrow scissors and wrapped her newborn in towels. "I thought I'd just gone to the toilet, looked down and saw her head," she recalled.
Bryony had experienced no pregnancy symptoms: no bump, continued periods, and had even gone on rollercoasters and trips abroad during what turned out to be her pregnancy. Her daughter, she later discovered, may have been up to two weeks overdue.
She was taken to hospital after calling 999, and later texted her mother: "I've just had a baby, not to worry, we're both fine."
Despite the initial shock, Bryony has since had a second child and is now using her experience to raise awareness about cryptic pregnancies, which affect an estimated 325 women in the UK each year.
Please note that this article is for guidance only. If you have any concerns about your own or your child's health, it is always best to consult your doctor or health professional.