What is the gestation period of mice? - briefly
The gestation period of mice is about 19–21 days. Females usually deliver litters ranging from five to twelve offspring.
What is the gestation period of mice? - in detail
The pregnancy of the common laboratory mouse lasts approximately 19–21 days, with the average reported as 20 days. Several variables modify this interval.
- Genetic background: Inbred strains such as C57BL/6 tend toward the lower end of the range, whereas outbred stocks may extend to 22 days.
- Ambient temperature: Housing at 20–22 °C supports the typical duration; cooler environments can lengthen gestation by 1–2 days, while higher temperatures may shorten it slightly.
- Maternal nutrition: Adequate protein and caloric intake maintain the standard timeline; severe restriction can delay parturition.
- Litter size: Larger litters often correlate with a marginally shorter gestation, whereas very small litters may experience a modest extension.
Embryonic development proceeds through defined stages within this period. By day 5–6, implantation is complete; organogenesis begins around day 8, and fetal growth accelerates from day 12 onward. By day 18, most organs are functional, and the pups are prepared for birth.
The gestational length influences postnatal outcomes. Shorter pregnancies are linked to lower birth weights, whereas prolonged gestation can increase pup viability but may also raise the risk of dystocia. Monitoring the expected delivery window enables timely intervention to reduce maternal and neonatal complications.