Sikiöaikaa

Sikiöaika, a Finnish term, refers to the gestation period—the time during which a fetus develops in the uterus, from conception (or fertilization) to birth. In humans, gestational age is typically counted from the first day of the last menstrual period, making a normal full-term pregnancy about 40 weeks (roughly nine months). Since fertilization usually occurs about two weeks after LMP, the actual embryonic development from conception is about 38 weeks.

The length of sikiöaika varies widely between species and individuals. In humans, the usual range is approximately 37 to 42 weeks. Among domestic animals, typical gestation lengths include dogs about 58–68 days, cats about 63–65 days, cows around 280–283 days, sheep about 145–155 days, and pigs roughly 112–115 days. Horses have longer pregnancies, generally about 330–345 days. In larger mammals such as elephants, gestation can exceed a year, often around 640–660 days. Genetic factors, maternal health and nutrition, and environmental conditions can influence the exact duration.

Measuring sikiöaika relies on ultrasound methods, especially in humans, where crown-rump length in early pregnancy and later fetal dimensions help estimate gestational age. In clinical and agricultural contexts, accurate dating is important for monitoring fetal development, planning care or breeding, and assessing risks related to preterm (before about 37 weeks) or post-term pregnancies.