Search results
Results from the WOW.Com Content Network
Large mammals develop at an absolute slower rate compared to small mammals. Thus, the large mammal tend have longer gestation periods than small mammal as they tend to produce larger neonate. [18] Large mammals require a longer period of time to attain any proportion of adult mass compared to small mammals. [19]
A pregnant lioness. In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus.
Timeline of human fertilization. In humans, pregnancy can be defined clinically, biochemically or biologically. Clinically, pregnancy starts from first day of the mother's last period. [4] Biochemically, pregnancy starts when a woman's human chorionic gonadotropin (hCG) levels rise above 25 mIU/mL. [5]
In human pregnancy, prenatal development is also called antenatal development. The development of the human embryo follows fertilization , and continues as fetal development . By the end of the tenth week of gestational age , the embryo has acquired its basic form and is referred to as a fetus .
In mammals, the term refers chiefly to the early stages of prenatal development, whereas the terms fetus and fetal development describe later stages. [2] [4] The main stages of animal embryonic development are as follows: The zygote undergoes a series of cell divisions (called cleavage) to form a structure called a morula.
Gestational age: 3 weeks and 0 days until 3 weeks and 6 days old. 22–28 days from last menstruation. Embryonic age: Week nr 2. 1 week old. 8–14 days from fertilization.
Pregnancy Timeline ©seksan wangjaisuk/Shutterstock.com. Dog pregnancies are typically divided into three stages: 1-3 Weeks: Small changes take place with a female dog’s body and behavior. It ...
Implantation is the first stage of gestation, and, when successful, the female is considered to be pregnant. [3] An implanted embryo is detected by the presence of increased levels of human chorionic gonadotropin (hCG) in a pregnancy test. [3] The implanted embryo will receive oxygen and nutrients in order to grow.