A cryptic pregnancy is a rare condition in which a person is pregnant but unaware of it, sometimes until very late in the pregnancy or even until labor begins. Unlike typical pregnancies, which are often recognized early due to missed periods and pregnancy symptoms like morning sickness or abdominal swelling, cryptic pregnancies can go undetected because the person may experience irregular or absent symptoms, have negative pregnancy test results, or interpret any symptoms as something else. Factors that contribute to cryptic pregnancies include irregular menstrual cycles (such as in polycystic ovary syndrome - PCOS), use of birth control, recent childbirth, or being in perimenopause. Some people may continue to have bleeding they mistake for periods during the pregnancy. Because of these atypical signs, the pregnancy may not be recognized until the baby is delivered or very close to delivery. Cryptic pregnancies are uncommon, with estimates around 1 in 475 pregnancies remaining undetected until about 20 weeks and about 1 in 2,500 going undetected until delivery. These pregnancies can lead to complications from missed prenatal care, such as increased risks of preterm birth or other pregnancy-related problems. In summary, a cryptic pregnancy is when a person does not realize they are pregnant for months or until birth, often due to minimal or absent pregnancy symptoms and confusing or misleading signs. It is sometimes called stealth pregnancy or denied pregnancy. This phenomenon has been studied medically and also featured in media shows about women discovering their pregnancy late or at labor.