Conception and The Three Stages of Fetus Development

The development of a child from conception to birth is an interesting and intricate process that takes nine months of development, so let’s see what all takes place. Firstly we must look into how an embryo is conceived. An embryo is conceived when sperm successfully fertilizes an egg, and it divides then travels to the endometrium (the implantation site). The placenta and amniotic sac actually start developing very early on, but will not amount to much until about 11 and a half weeks. It begins developing 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 with the baby developing in a variety of different ways. No trimester is “the most important” as they are all extremely crucial in correctly developing a child. Pregnancies last an around 40 weeks, sometimes a little more, sometimes a little less. Now, with this being said, you can have a baby earlier than 40 weeks and it still live if taken care of by doctors after birth for a few weeks.

The first trimester is week 1-12, and a lot happens in these few weeks. During the first trimester is when the baby grows the most, even though it's only twelve short weeks. You wont notice much happening in the first three weeks, this is because the embryo is beginning to form from the egg, but by week four the fetus’s face begins to develop, forming the beginnings of eyes and a nose. Week five the tube that will become the fetus’s heart begins forming, as well as skin. Week six the fetus develops limbs (arms, legs, hands, feet). Week eight a lot happens, firstly hair follicles and nails begin to form, as well as the retina. The brain and taste receptors develop aslo, and depending on the positioning of your uterus you may be able to hear the heartbeat. By week ten, fingers and toes start to form.

The second trimester is from week 13-27. Women begin to show a larger belly in this trimester as the fetus grows larger. Eyebrows, nails, eyelids, and eyelashes become fully formed and the teeth and bones densen. The nervous system, reproductive organs and genitals are formed, this is when you can find out if you’re having a boy or a girl. In the fifth month, muscles develop so you can start to feel the fetus move. Hair called “lanugo” is developed, this hair covers the fetus’s shoulders, back and temples. This is used as protection against the amniotic fluid and is normally shed before birth. A white coating over the fetus’s skin called “vernix caseosa” also helps protect the fetus from the amniotic fluid, and is shed before birth like the lanugo.

The fetus starts developing eyelids that can open in the 6th month, as well as fingerprints and toe prints. Another interesting fact is that the fetus will now weigh more than the placenta. The fetus can now react to sound and light, as the ears are developed as well as the eyes. Infact, a fetus may “jump” at a sudden loud sound. Fetus’s can now yawn, suck their thumb, and may even sometimes hiccup! If your fetus is born prematurely at 23 weeks, it can be saved by doctors as well. Lastly is the third trimester, birth will soon occur.

The third trimester is from week 29 to 40, but birth may occur earlier. In the third trimester, not too much happens (compared to the others).

The fetus’s skin will become pink and smooth, unlike in the second trimester where it was transparent and had the vernix caseosa over it. Fat begins to become deposited throughout and hearing is fully developed. Most organs are fully developed, except the brain and lungs. The brain develops rapidly in the third trimester and the lungs will develop as well. In the last month, all organs are fully developed and the fetus reacts well to sounds, light, can grasp things and blink as well. The fetus will “flip” ready to be born as well.

Knowing now how much a fetus develops over the course of nine months is very interesting. With how much the fetus grows, nine months is an insanely quick amount of time considering a fetus starts as a small bunch of cells and slowly forms to be a living, breathing human being. Seeing what exactly goes into the development is an interesting and enlightening bit of information that all should be made aware of.