Terms like 'cryptic', 'stealth' or 'invisible' are not words you often hear used when discussing pregnancy.
These pertain to a person who has no idea that they're pregnant, often until they're in the midst of labour.
They refer to someone who is pregnant, but isn't exhibiting the more common and visible signs of gestation; for example, a baby bump, and therefore may not consider the idea that they're expecting.
It's the type of phenomenon that makes you say, "That could never happen to me!"
However, the fact is that it can happen and when it does, there will likely be many questions as to why?
A GP has taken to TikTok to explain how and why a pregnancy can go unnoticed until it’s time to welcome baby into the world.
Dr Karan Rajan, an NHS surgeon, who has garnered over 5 million followers, took the opportunity to educate users on this medical wonder after a creator shared that during her pregnancy, she never grew a bump.
"At first I didn't think anything of it because it was early on. But then as the months went by, I still had nothing," the user explained.
Dr Rajan used this woman's experience to explain why some expectant mums may not grow a bump.
"Fun fact, sometimes a pregnancy can be invisible, with the baby in cloud storage," he explained, adding that one reason may be a retroverted uterus.
"Most women have an anteverted uterus, [meaning] it's slightly tilted forwards. But one in five have a backwards tilt towards the spine."
For some women, the uterus may be tilted backwards for the full term of their pregnancy, according to the surgeon.
"This 'backwards growth' could hide any bump," he adds.
However, there are other reasons that may lead to an invisible pregnancy, according to Dr. Rajan.
These include previous surgery, endometriosis and other gynaecological conditions that could scar the uterosacral ligament.
"These are basically biological anchors which keep the uterus fixed to the spine and inside the pelvic cavities.
"If these are stiff because of scarring, these ligaments can literally hold the uterus back and stop it from protruding too far out," he explained.
@dr.karanr Invisible pregnancy! @nikki salazar ♬ original sound - Dr Karan Raj
He also says that taller people also have a higher chance of not having a noticeable bump during their pregnancies.
"If you're taller, you'll have a longer torso so there'll be more space for the uterus to develop upwards rather than just outwards."
Those with 'well developed' abs may also 'develop closer to your core rather than protruding out'.
According to the HSE, these include:
