Cryptic pregnancy

The term cryptic pregnancy is used by medical professionals to describe a pregnancy that is not recognized by the person who is pregnant until they are in labor or have given birth. The term is also used online for a special form of false pregnancy (pseudocyesis), or delusion of pregnancy, in which a person who has no medical verification of pregnancy believes that they are pregnant.
Medically cryptic pregnancies.
The television series "I Didn't Know I Was Pregnant" shared the stories of women who had experienced medically cryptic pregnancies. They didn't realize they were pregnant until they were in labor or had given birth. Nearly all the featured stories involved women who continued to have their period as usual throughout their pregnancy, while some cited not having regular periods due to polycystic ovarian syndrome (PCOS), or other conditions that are associated with infertility. The women involved often did not gain weight or experience other major symptoms of pregnancy, such as morning sickness or breast sensitivity. Those who did experience some symptoms of pregnancy either claimed to attribute the symptoms to an existing condition, claimed to have taken a home pregnancy test and gotten a negative result, or both.
A few of the stories involved women who had known they were pregnant and experienced an early miscarriage, only to realize they were still pregnant when the baby was being born. It is common that after the birth the new parent looks back and realizes that there were some signs of pregnancy they had ignored. For women who have had a typical pregnancy, the assumption is that there is no way to not "feel" a pregnancy. However, obstetricians on the show explained that, depending on the position of the placenta, the sensations of a baby moving can be minimal. In 2015, the show's spin off, "I Still Didn't Know I Was Pregnant", featured women who had experienced multiple medically cryptic pregnancies.
Causes.
The causes of medically cryptic pregnancies are either physiological, that is, there were no recognizable symptoms of pregnancy, or can be due to psychological problems. For example, denied pregnancy is a condition in which a woman is mentally unable to accept that she is pregnant and so may go part way or all the way through a pregnancy unconscious of her pregnancy. This phenomenon is sometimes linked to other mental health diagnostic labels. However, denied pregnancy makes up only a proportion of all unknown pregnancies.
Epidemiology.
1 in 7,225 pregnancies are unknown at the time the mother gives birth.
In history.
Pope Joan, a character from 14th century European literature is said to have been a pope during the 9th century in the guise of a man until she went into labor while on procession. Though modern scholars consider her to be a fictional character, it shows a recognition of medically cryptic pregnancies in the European Middle Ages.
Cryptic pregnancy as a delusion of pregnancy.
The Gilmour Foundation, an Internet-based foundation which styles itself as an expert on cryptic pregnancy, claims a cryptic pregnancy is one that is missed by pregnancy tests and ultrasounds. They claim these pregnancies occur because of an abnormally slow-growing fetus, and gestate for years or even decades. The foundation has said that this causes the human chorionic gonadotropin (hCG) hormone to be too low to be detected by medical tests and, because the pregnancy is smaller or located outside the uterus, it is missed on ultrasounds. However, there is no medical literature to support the existence of cryptic pregnancy as described by the Gilmour Foundation. Rather, this type of "cryptic pregnancy" should be understood as a form of delusion.
Causes.
For the most part, this form of cryptic pregnancy is a psychological issue. Some people with this mental illness show symptoms of pregnancy, such as amenorrhea, weight gain, nausea, etc., which could be caused by the delusion or by its underlying cause.
"Dr. Phil Show".
"Dr. Phil" featured women on his talk show who believed they had been pregnant for years with a cryptic pregnancy. Despite negative urine and blood tests, and medical imaging of their abdomens showing no pregnancy, the women persisted in their belief they were pregnant, including one who had had a tubal ligation in her early 20s. Dr. Thais Aliabadi was the expert guest on the show and explained that many women claim to have a cryptic pregnancy to explain physical symptoms they associate with pregnancy, such as weight gain in the abdomen, mood swings, sore breasts and food cravings.
In history.
Queen Mary I of England is rumored to have experienced false pregnancy, which may be considered cryptic, because she continued to believe she was pregnant past the expected due month. However, because of the limitations of medical technology, and the delicacy of inspecting the body of the queen, doctors would have had great difficulty in verifying a pregnancy, including whether it was a tumor or a molar pregnancy. During one of her false pregnancies, Mary believed herself to be pregnant for nearly a year after her period stopped, when suddenly her abdomen flattened without her going into labor. 