fóstri

Fóstri is the Icelandic term for a developing mammal inside the uterus, most commonly a human fetus during pregnancy. The word is used in medical, educational, and everyday language to refer to the unborn offspring from conception until birth. The fóstri is connected to the placenta and umbilical cord, through which nutrients and oxygen are supplied and waste products removed.

Pregnancy lasts about 40 weeks from conception. Fóstral development is commonly described in three trimesters: the first trimester (weeks 1–12) involves implantation, formation of major organs, and the beginning of a heartbeat; the second trimester (weeks 13–26) brings growth, movement, and further maturation of organ systems; the third trimester (weeks 27–40) supports rapid growth and preparation for survival after birth. Viability outside the womb begins around mid-pregnancy with modern care, usually around 24 weeks, with outcomes improving as gestation progresses.

Healthcare providers monitor the fóstri with ultrasound imaging, fetal heart rate assessment, and screening tests for genetic conditions and fetal anomalies. They may also track fetal growth, amniotic fluid levels, and maternal health factors such as blood pressure and diabetes, all of which can affect fetal well-being and planning for delivery.

Ethical and legal considerations regarding the fóstri vary by country and culture, and discussions in obstetrics address fetal rights, maternal autonomy, and options surrounding pregnancy termination. In clinical practice, the focus is on ensuring the health and safety of both the pregnant person and the fóstri.

Fóstri remains a central focus of obstetrics, neonatology, and prenatal medicine, guiding research, screening programs, and perinatal care.