After the fertilization of sperm and ova, the egg develops that rapidly divides into many cells which reach the fallopian tube and remain there for three days. Then the fertilized egg is passed to the uterus and persists in dividing slowly, where it attaches to the endometrium for implantation. The further growth and development of the fetus occur in the uterus where the period is divided into three stages as:

First Trimester: From Fertilization to Baby's Development

First Trimester: After the baby is conceived, this period begins and spans 12 weeks. It constitutes the first 3 months of pregnancy where the fertilized egg is divided into cells that will change into a fetus. The fetus begins to develop baby-like features where after three months all the organs and limbs are present. Generally, it is about 4 inches long.

Second Trimester: Comfortable and Baby-Like Features

Second Trimester: This is the second stage of pregnancy which has to be the best experience and remains up to 7 months or 28 weeks. The discomfort and symptoms of early pregnancy are no longer here. Facial features along with some movement are seen in the developing fetus, where it also responds to stimuli as well. The fetus is generally 14 inches long at the end of the seventh month and weighs between 2-4 pounds.

Third Trimester: Fetus is Fully Prepared for Birth

Third Trimester: This is the last stage of pregnancy which remains up to 40 weeks or 9-10 months (in some cases). During this stage, the fetus starts to gain weight along with body fat. Lungs are almost fully developed along with the brain, internal organs and other reflexes that begin to coordinate like the closing eyes, turning the head etc. The fetus is generally 17-19 inches long and weighs 5-6 ½ pounds. Finally, at the time of labour fetus is developed with all the organs and is prepared for birth.
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