“Gave birth without knowing about the pregnancy”... Pregnancy discovered at 9 months—is it common? [Smart Wellness]

[Financial News] A story about someone who did not learn she was pregnant until she had entered her ninth month was recently featured on the MBC variety show Oh Eun Young's Report: Marriage Hell, drawing widespread attention. It may be hard to believe that someone could go without realizing she was pregnant until childbirth was imminent, but medically, this can certainly happen. However, because delayed prenatal checkups can have potentially devastating effects on the health of both mother and fetus, it is important to pay close attention to even subtle changes in the body.

In medical circles, a condition in which a pregnant woman does not realize she is pregnant until late in pregnancy or just before delivery is called “cryptic pregnancy” or “concealed pregnancy.”
According to academic reports, 1 in 475 pregnant women do not know they are pregnant after 20 weeks, while about 1 in 2,500 remain unaware until just before delivery.
In 2025, the BBC in the UK reported on a woman in her 20s who gave birth suddenly due to a cryptic pregnancy and cut the baby’s umbilical cord with an eyebrow razor. The report noted that around 325 unexpected births occur in the UK each year. A 2024 case report on cryptic pregnancy was also published in the international medical journal BMJ Case Reports. It described a case in which pregnancy symptoms were mistaken for simple obesity and illness for six months, and the patient gave birth at full term in an emergency room.

Experts explain that cryptic pregnancy is not caused by a lack of attention, but can occur when several physical factors come together.
First, menstrual irregularity can be confused with abnormal bleeding. Women whose periods are irregular due to conditions such as polycystic ovary syndrome may be inclined to dismiss the absence of menstruation as unimportant. Even if bleeding occurs during early implantation or while the placenta is forming, they may mistake it for their usual irregular period and rule out the possibility of pregnancy.
Fetal movement may also go unnoticed when the placenta is positioned at the front of the uterus, a condition known as an anterior placenta. The placenta, which normally supplies oxygen and nutrients to the fetus and removes waste, is usually located at the back or top of the uterus. But when it settles against the front wall of the uterus, just inside the abdomen, it acts like a cushion, absorbing the baby’s movements. As a result, fetal movement may not be felt clearly and can easily be mistaken for discomfort caused by indigestion or abdominal gas.
The abdomen may also be less prominent in someone with a retroverted uterus, a deep-set pelvis, abdominal obesity, or strong abdominal muscles. When the belly grows gradually or looks small for the stage of pregnancy, many people attribute it to ordinary weight gain.
A pregnancy test may also produce a “false negative.” After the middle of pregnancy, levels of the hormone used to determine pregnancy (hCG) rise sharply. In that case, the test reagent may become saturated, preventing the line that indicates pregnancy from appearing. This is known as the “high-concentration hook effect” (hook effect).
People who are breastfeeding after a recent birth or going through the menopausal transition may also interpret pregnancy symptoms as simple amenorrhea or mistake them for symptoms of menopause.

Cryptic pregnancy is dangerous because essential nutrients such as folic acid—which helps prevent neural tube defects and supports cell division—may be lacking during early pregnancy, when the fetus’s major organs and nervous system are forming. The fetus may also be left unprotected from alcohol or drugs, which can have devastating effects such as birth defects or developmental delays.
In severe cases, preeclampsia or placental abnormalities may go undetected until it is too late, putting both mother and fetus at risk during delivery. This can also lead to a premature or low-birth-weight baby.
Above all, preventing cryptic pregnancy means paying attention to changes in the body. Even if you have polycystic ovary syndrome or usually have irregular periods, take note if the gap between periods reaches two months or more, or if your bleeding differs from usual. If unexplained weight changes, abdominal bloating, or indigestion persist, it is safer to see a gynecologist and get an ultrasound.

[email protected] Kim Hyeon-seon Reporter