gestatiós

Gestatiós, commonly referred to as gestation, is the period of prenatal development during pregnancy when a fetus grows and matures inside the uterus. In humans, gestational age is typically measured from the first day of the last menstrual period (LMP), averaging about 40 weeks from LMP or roughly 38 weeks from conception.

Gestation is traditionally divided into three trimesters. The first trimester (weeks 1–12) involves fertilization, implantation, and early organ formation, with rapid development of the embryo and the beginning of organ systems. The second trimester (weeks 13–26) features continued growth and maturation, improved fetal movement perception by the mother, and more detailed anatomy assessment via ultrasound. The third trimester (weeks 27–40) emphasizes rapid fetal growth, organ system readiness for life outside the womb, and final preparation for birth.

Key milestones include detectable fetal heart activity around 6 weeks, neural tube closure early in the first month, and progressive development of organs and body systems. Viability, the point at which a fetus has a reasonable chance of surviving outside the womb, increases with gestational age and is typically around 24 weeks with advancing medical care.

Prenatal care supports healthy gestation through regular medical checkups, ultrasound dating, screening tests, and guidance on nutrition, avoidance of harmful substances, and management of conditions such as gestational diabetes or hypertensive disorders. Common outcomes are term birth (37–42 weeks), preterm birth (before 37 weeks), or post-term birth (after 42 weeks). Miscarriage refers to spontaneous pregnancy loss before about 20 weeks.

Variability exists in gestation lengths across individuals and species, but the above framework guides medical assessment and obstetric planning.