The development of a child from conception to birth is an interesting and complex process that takes nine months of development, so let's see what happens. We must first look at how an embryo is conceived. An embryo is conceived when sperm successfully fertilizes an egg, and it divides and then travels to the endometrium (the implantation site). The placenta and amniotic sac do indeed begin to develop very early, but will not develop much until around 11 1/2 weeks. It begins to develop around the blastocyst which “holds” the embryonic pole, which implants and becomes the embryo. Now, once the baby is conceived, what happens? Well, in a pregnancy there are three trimesters, each in which the baby develops in different ways. No one trimester is “most important,” as they are all extremely crucial to a child’s healthy development. Pregnancies last about 40 weeks, sometimes a little more, sometimes a little less. That being said, you can have a baby before 40 weeks and they may still live if they are cared for by doctors after birth for a few weeks. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get an original essay The first trimester runs from week 1 to 12, and a lot happens in those few weeks. The baby grows the most during the first trimester, although it only lasts twelve weeks. You won't notice much happening in the first three weeks, as the embryo begins to form from the egg, but by the fourth week the face of the fetus begins to develop, forming the beginnings eyes and nose. Fifth week, the tube that will become the heart of the fetus begins to form, as well as the skin. Sixth week, the fetus develops limbs (arms, legs, hands, feet). In the eighth week, a lot happens: first of all, hair follicles and nails begin to form, as well as the retina. The brain and taste receptors also develop, and depending on the position of your uterus, you may be able to hear the heartbeat. By the tenth week, fingers and toes begin to form. The second trimester runs from week 13 to 27. Women begin to show a larger belly during this trimester as the fetus grows. Eyebrows, nails, eyelids and eyelashes fully form and teeth and bones become denser. The nervous system, reproductive organs and genitals are formed, this is when you will be able to know if you are expecting a boy or a girl. By the fifth month, the muscles are developing and you may begin to feel the fetus moving. Hair called “lanugo” is developed, this hair covers the shoulders, back and temples of the fetus. This is used as protection against amniotic fluid and is normally excreted before birth. A white layer on the fetal skin called "vernix caseosa" also helps protect the fetus from amniotic fluid and is excreted before birth, like lanugo. The fetus begins to develop eyelids that can open at the 6th month, as well as fingerprints and toes. prints. Another interesting fact is that the fetus now weighs more than the placenta. The fetus can now respond to sound and light as its ears and eyes develop. In fact, a fetus can “jump” at a sudden, loud sound. Fetuses can now yawn, suck their thumbs and sometimes even hiccup! If your fetus is born prematurely at 23 weeks, it can also be saved by.