Question

How many trimesters are there in human pregnancy?

Answer 1

The time taken by the embryo to develop into a foetus in a viviparous animal is known as gestation. It is the period between conception and childbirth. In humans, the gestation period is 280 days or 40 weeks.

Complete answer:
The viviparous organisms are the organisms that produce the young ones and in which the baby is developed inside the womb of the mother. This development period between conception and childbirth is known as the gestation period. It is different for different animals.

Let us discuss the gestational period in humans.
In the case of humans, gestation starts when the female parent misses her menstrual phase of the menstruation cycle. During this, the human Chorionic Gonadotropin level rises. Human gestation lasts for 280 days or 40 weeks which is divided into three trimesters. Each trimester comprises of three months. The duration of the first trimester is the last menstrual period through 13 weeks. The second trimester is 14-27 weeks and the third is 28-42 weeks. The labour can start about 40 weeks. The labour before 37 weeks is called preterm labour. During each trimester there are several developmental changes occurring in the foetus and lasts until childbirth.

Thus, we can conclude that there are three trimesters in human pregnancy.

Note: The gestational age of the foetus can be determined by knowing the weight, head circumference, and position. The maximum gestation period in the case of terrestrial animals is that of elephants. The baby born is around 100 kgs in weight.