Feto

Feto is the term used in several Romance languages, including Spanish, Portuguese, Italian, and Romanian, to refer to a developing mammal inside the uterus after the embryonic stage. In English, the corresponding term is fetus. The word feto comes from Latin fetus, meaning offspring or that which has been produced.

In human development, the fetal period begins after the embryonic period, roughly around the ninth week after fertilization and continues until birth. During this stage, the major organs have formed, and the organism grows and matures. Growth includes increases in size and weight, development of the nervous system, lungs, and other systems, and refinements of body structures. The length of gestation varies, but most pregnancies reach around 38 to 42 weeks from the last menstrual period.

Prenatal care includes regular medical checkups, ultrasound imaging, and screening tests to monitor fetal development, detect congenital anomalies, and assess fetal well-being. A fetal heartbeat can usually be detected by ultrasound or Doppler technologies around six weeks after fertilization. Ultrasound is also used to estimate gestational age and growth. Some pregnancies experience complications such as fetal growth restriction or distress, which require medical management.

Viability outside the womb—the ability of the fetus to survive after birth with medical support—improves with advances in neonatal care, and is generally considered around 24 weeks gestation or later, though survival chances vary by case and resources.

Terminology varies by language and context. The distinction between embryo and fetus marks the transition from organ formation to growth and maturation. In biomedical literature, the term fetus is standard for human development after the embryonic stage.