The week 4 begins like any other week. This is because there is some more time left before you know whether you have missed your period. Though, on the outside everything looks normal, your body is undergoing great changes to accommodate the growing baby in your womb.
Following the ovulation, fertilization and conception taking place successfully; by fourth week the blastocyst is firmly embedded in your uterus. This is the time for more advanced development of your baby. Normally, your body would be getting ready for the next menstrual period by this time; but your pregnancy will trigger new hormonal secretions that will prevent this from happening.
Let us have a detailed look into what is happening inside your body when 4 weeks pregnant.
Word of Precaution:
Before you start reading the article, remember that every baby and pregnancy is unique and this is just the generic information of what takes place during 4 week pregnancy. Your pregnancy or development of your baby
Changes Taking Place Inside Your Body:
The two week period following your ovulation is known as the luteal phase. Corpus luteum, which is a collapsed follicle that has remained behind after releasing the ovum, plays a major role in the changes taking place in your body during this period. Hence this phase is known as the luteal phase.
The corpus luteum increases the production of progesterone, which in turn warms up your body and uterus for embryo. Simultaneously it thickens the endometrium, and increases the blood supply which creates a soft cushion like condition to catch the blastocyst when it arrives.
Your brain has already been informed by your reproductive system to stop the procedure of menstruation. Your body signifies what is best for your foetus through hormonal signals and triggers.
Another major change you observe in your body is the secretion of hCG (human chorionic gonadotropin)hormone. The level of hCG in your body increases rapidly during the first few weeks of pregnancy; it doubles itself almost every day. This hormone is responsible for detection of pregnancy in pregnancy tests.
Inside Your Uterus:
By the beginning of the gestational 4 week pregnancy, the blastocyst is comfortably settled in your uterus. Your uterus has undergone enough changes and has made the epithelium of the uterine wall suitable for the reception of the blastocyst. If the endometrial epithelium is not properly prepared for implantation, the blastocyst will fail in attaching itself to it.
The unicellular zygote which was created few days ago now consists of an inner cell masses that constitute embryoblast, trophoblast and a primary yolk sac by the 4th week of pregnancy. The embryoblast will develop into an embryo and the trophoblast will develop into the placenta.
By this time, a second cavity has appeared within the inner cell mass which later enlarges to become an amniotic cavity. Most of cells that make up the amniotic cavity come from inner cell mass, but some cells are borrowed from the trophoblast.
The placenta cells are tunnelling away into the interior lining of your uterus with their microscopic tentacles known as chorionic villi. The placenta may become fully functional by the end of the week, but at present it is unable to provide nutrients or take away the waste produced by the developing foetus.
Slowly the placenta begins to grow and embed itself in the uterine wall. It is made of two distinct layers at this point. The cells of the placenta are implanting themselves and creating space inside the lining of uterus so that there is a channel created for the blood to flow inside the developed placenta.
The amniotic sac will protect the foetus by cushioning it from any possible damaging pressure which may arise inside the womb by keeping it comfortable, in addition to preventing dehydration of foetal tissues. The yolk sac delivers nutrients to the foetus, since the placenta will take time to develop. It also begins to produce the red blood cells.
[ Read: 5 Weeks Pregnant ]
Connecting With Your Baby:
Your tiny baby who is now a foetus is establishing its connections with you by growing long projections into the uterine walls. Isn’t that amazing? The tiny little hair like tendrils that enfold around the copious small blood vessels in the lining of your uterus, will develop into a placenta. This is the time when the embryo will develop a membrane around itself which is also the inner layer of the developing placenta.
The membrane known as chorion, establishes a connection between your uterus and your baby, which will continue until child birth. The tendrils provide oxygen and nutrients to the growing foetus until the placenta is fully formed. From now on, you are responsible for providing oxygen and nutrients for the developing baby to survive. It is a great responsibility, but fortunately nature has made every mother fit to carry that duty with natural ease.