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For mammals, the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. [1] The duration of this period varies between species. For most species, the amount a fetus grows before birth determines the length of the gestation period. Smaller species normally have a shorter gestation period than ...
Gestation, called pregnancy in humans, is the period of time during which the fetus develops, dividing via mitosis inside the female. During this time, the fetus receives all of its nutrition and oxygenated blood from the female, filtered through the placenta , which is attached to the fetus' abdomen via an umbilical cord .
Humans, unlike most other species, have concealed ovulation, a lack of obvious external signs to signal estral receptivity at ovulation (i.e., the ability to become pregnant). Some species of animals with estrous cycles have unmistakable outward displays of receptivity, ranging from engorged and colorful genitals to behavioral changes like ...
List of mammalian gestation durations. This is a collection of lists of mammal gestation period estimated by experts in their fields. The mammals included are only viviparous (marsupials and placentals) as some mammals, which are monotremes (including platypuses and echidnas) lay their eggs. A marsupial has a short gestation period, typically ...
Gestation. Drawing of a fetus in utero. Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). [1] It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for ...
“The most likely time to get pregnant is around the time of ovulation,” Frugoni says. This usually happens approximately 14 days before the next period, although this will differ from person ...
Immunologically, an embryo or fetus of an interspecific pregnancy would be equivalent to xenografts rather than allografts, [1] putting a higher demand on gestational immune tolerance in order to avoid an immune reaction toward the fetus. [1] Some mice experiments indicate an imbalance between Th 1 and Th 2 helper cells with a predominance of ...
Superfetation (also spelled superfoetation – see fetus) is the simultaneous occurrence of more than one stage of developing offspring in the same animal. [ 1 ] [ 2 ] [ 3 ] In mammals , it manifests as the formation of an embryo from a subsequent menstrual cycle, while another embryo or fetus is already present in the uterus .