The Baby in the Womb

Your baby starts life as a single cell when the egg and sperm fuse at conception. From this single cell the baby’s body will develop as will the placenta that will provide it with nourishment until birth. About one week after conception a cluster of cells has formed, the inner layer of which will become the embryo. The outer layer of this cluster will then become the placenta, umbilical cord and the amniotic sac. These will provide your baby with all that it needs to survive until birth.


The Umbilical Cord and Placenta


The placenta is the connection between you and your baby. It is a link between your own circulatory system and your baby’s. The placenta is the means by which your baby receives oxygen and all sorts of substances such as antibodies, sugar, amino acids, vitamins and minerals from you. Your diet and health have a great bearing on the placenta and how it nourishes your baby. The placenta also acts as a barrier to baby in wombstop harmful substances and germs from infecting your baby.


Contrary to popular thought, you do not share blood with your baby and only a very tiny amount of your baby’s blood passes into your bloodstream. The placenta grows as cells bed down into the endometrial lining of the uterus. Here they develop into tissues called villi that attach to the uterine wall. The villi are made up of my minute foetal blood vessels covered in connective tissue enveloped in a membrane covered in placental cells. These cells are bathed by your own blood as they attach to the wall of the uterine blood vessels. They prevent your own blood cells from passing through but take nutrients and oxygen from them into the villi and then from there to the baby’s own blood stream. Just over two months following conception the villi have rooted themselves thoroughly and the placenta starts to work with full affect.


The Umbilical Cord


Thousands of blood vessels from the villi combine to form the foetal vein and the two foetal arteries inside the umbilical cord. The cord is connected via your baby’s navel to the middle of the placenta. Blood is carried by the foetal vein and transports nutrients, antibodies and oxygen to your baby from your placenta. Waste products are carried by the arteries from the baby back to the placenta and from there they enter your bloodstream and are processed by your kidneys and eventually are discharged in urine. The main function of the placenta is to provide your baby with protection against infection and toxins, and also ensure that it gains sufficient nourishment from your bloodstream. Oxygen enters into your baby’s bloodstream through a process of diffusion. This is because you have more oxygen in your own blood than the baby does. Where however, you have a concentration of substances lower than that of your baby’s, such as certain minerals, they are transported into your baby’s bloodstream through a process known as facilitated diffusion.


Dangers present in the blood such as germs are filtered out by the villi. The villi not only stand guard to protect your baby from infection but also transfer antibodies from yourself to your child’s bloodstream. The umbilical cord and placenta develop along with your baby. The embryo is completely surrounded by the villi and associated tissues in early pregnancy. By about week ten a few of the villi develop into a spherically shaped area on the uterus and eventually form the placenta. The placenta is fully developed after three months, that will eventually grow to about 8 inches in diameter and weigh approximately 1 pound at full term.


The umbilical cord takes root at the middle of the placenta and grows to approximately 3 feet in length. Once your baby is born the placenta is housed in a spongy layer connected to the wall of your uterus and over time your uterus will shrink leaving the placenta to fall off.


Hormones and the Placenta


Both your baby and the placenta produce hormones. The embryo has a fully developed endocrine system. The hormones produced by the placenta are transported into your own blood stream and optimise your body for childbirth. The baby also gains hormones from the placenta that you produce. This enables the baby to share in your own emotional profile as the different types of hormones you produce affect not only your own mood but the mood of your baby.


HCG or placental human chorionic gonadotropin stimulates the corpus luteum in the ovary causing it to produce progesterone and oestrogen. This continues for about 10 weeks and then the placenta takes over production of these hormones. Pregnancy is actually maintained by the production of progesterone as it allows the muscle of the uterus to develop, among other things. Hormones will be produced by your placenta for the rest of the pregnancy. The combination of hormones that your baby produces and those which your own body releases set the timing for the different stages of pregnancy. They have a great bearing on your emotional state and also prepare you for nurturing the baby after birth. Growth factors are produced by the placenta that control the ovaries, insulin and glucose levels, and the production of interferon that controls some aspects of immune system functioning.


Amniotic Fluid and Amniotic Sac


All the while your baby is inside your womb it floats in amniotic fluid which is housed inside the amniotic sac. The amniotic sac consists of two membranes, the outer one is known as the chorion. This initially develops from villi in the placenta. The womb is lined by the chorion. The inner membrane is known as the amnion. These two membranes form a barrier that guard the baby throughout pregnancy.


Amniotic fluid is similar in appearance to water but smells sweet. During the early phases of pregnancy it permeates into the membranes through your own body cells and then flows in and out through your baby’s skin. Eventually, most of the amniotic fluid is produced by the baby. She will absorb it into her own blood stream and even breathes and drinks it. She then urinates it out. Luckily, this does not pollute the womb because there are no bacteria present in her urine. All waste products are excreted by the baby through the placenta, so the amniotic fluid remains pure.


The amniotic fluid performs many functions. It acts as a buffer against impacts that could occur to your own body. In this way it works like a shock absorber protecting the baby from sudden jolts. It also contains nutrients such as amino acids, carbohydrates, minerals and salts. It never stagnates because it is renewed approximately every 5 hours. It keeps the baby at a set temperature even though you yourself may be exposed to extreme heat or cold.


Room in the Womb


During the early stages of pregnancy there is a higher ratio of fluid to your baby’s own volume. At this time the baby has plenty of space to move around in and probably does not experience any sensation of gravity. This mobility allows the baby to develop its limbs as it recoils and kicks and moves around inside the womb. As pregnancy progresses, the amount of amniotic fluid increases but so does the size of the baby. The nearer it gets to due date the less room the baby has to manoeuvre in and the more of her own weight she is conscious of.


Breaking Waters


When you break your waters, it is actually the two membranes of the amniotic sac which burst. At that point the amniotic sac holds between one and 3 pints of fluid. The break in the membranes is where your baby’s head pushes out from. During placental delivery these membranes are also delivered being attached to the placenta.


Healthy Pregnancy = Healthy Adult


The health of both mother and baby following birth is dependent on your ongoing health throughout pregnancy. There have been scientific studies that link this relationship from womb to later life. Children that are conceived in a less than optimal environment can suffer even in adulthood through ill health related to this time. A big factor is maternal hormones and nutrients which pass from mother to child via the placenta. This plays a big part in the development of internal organs and it has been proven through long-term studies that difficulties during gestation can definitely affect organ health in adult life. So it is important to take this time of foetal and embryonic development seriously in regards to optimum health and nutrition as it will pay dividends in years to come.

14. July 2010 by Cheryl Brady
Categories: Childbirth, Growth | Tags: , , , | Leave a comment