gestating

Gestating refers to the process of carrying a developing embryo or fetus within the uterus. In humans and other mammals, gestation is the period between conception and birth. The term emphasizes the developmental phase of the offspring within the womb, as distinct from fertilization or parturition.

In humans, gestational length is commonly cited as 38 to 42 weeks from conception, or about 40 weeks from the first day of the last menstrual period. Clinically, gestational age guides prenatal care. The three trimesters describe stages of development: first trimester (conception to about 12 weeks), second (about 13 to 26 weeks), and third (about 27 to 40 weeks).

Determining gestational age relies on dating methods such as menstrual history and ultrasound. Prenatal care includes maternal health monitoring, fetal growth assessment, nutrition, and screening for genetic or fetal conditions. Common complications associated with gestation include gestational diabetes, preeclampsia, and hyperemesis gravidarum; these require medical management to reduce risks for mother and baby.

The length of gestation varies widely among species. Humans average around 40 weeks, while dogs gestate about 9 weeks (63 days), cats about 64–66 days, cows around 280 days, and horses about 11 months. The term gestating is used for both human and animal pregnancies; in many animals the gestation period is adapted to the species' reproductive biology. The word derives from Latin gestare, meaning to carry.