4th week of pregnancy

After fertilization we arrive at week 4 of pregnancy, which is considered second development: is when the embryo implants itself in the wall of the uterus (the place where she will grow and prepare to go outside on the day of delivery). The correspondence is with days 21 to 28 of the menstrual cycle; but menstruation has been stopped by the hormone human chorionic gonadotropin (HGC) which is what pregnancy tests detect. Therefore the absence of menstruation - especially if pregnancy is sought - is the first sign to observe; And remember that if your suspicions are confirmed you should (if you have not already done so) start taking folic acid supplementation, as indicated here (400 mg daily).

Between this week and the next is when we usually ask for a pregnancy test at the pharmacy or Family Planning Center: if the rules are irregular, Perhaps it is convenient to wait a few days, although I know that in this circumstance patience is conspicuous by its absence. If you buy the pregnancy determination kit, read the instructions carefully, and always perform the test with the first urine in the morning; HGC remains continuously in the urine, but this is when the concentrations are highest, and performing the test at noon could give a confusing result. The lack of menstrual bleeding is the first warning, and if it is a wanted pregnancy, it is inevitable to feel a twinge of illusion, but there are more signs, and they are unmistakable (for those who have already had one or more pregnancies).
Nausea or dizziness may appear, and you are sure to be tired; it is also common to feel tension in the breasts. Although the sensations are similar to those we have with premenstrual syndrome (with the exception of the sadness that sometimes accompanies the latter), it is intuition that alerts some moms; Y the two pink lines that confirm to all of us that the pregnancy has been achieved! But let's not go so fast and go back to that implantation.

The embryo looks for a house

After fertilization, the blastocyst (the embryonic phase has yet to begin) descends to the uterus and generates small extensions that embed (or bury) it in the endometrium: implantation has concluded and the being that will develop from this cell division already has a home. At the same time, the formation of the placenta and the amniotic cavity begins.

The size of the small implanted embryo prevents the ultrasound from detecting it, although a vaginal ultrasound could help to see the yolk sac without evidence that new life is pushing hard inside. There is only another week left for you to see it, and I know that even if I tell you that there is no rush, you do have it; It won't do you much good if I tell you that if your baby is already with you, you can just take care of yourself and take care of him, and go to the appointments scheduled by the midwife and the gynecologist. Fortunately, today we have at our disposal a lot of information, and virtual spaces where we can share with other mothers. However, I repeat: relax and enjoy this new stage of your life, contrast data when necessary and let yourself be carried away by instinct and the advice given by health professionals.

Implantation bleeding - nothing to worry about

The embryo is small but its three layers of cells form different tissues: the inner one will become organs; the average in the skeletal, muscular, excretory and cardiovascular systems; the external will become skin, hair, eyes and nervous system. Well, this is very, very briefly; but of course Nature works perfectly, there is no doubt that she knows what she is doing :).

This week what we know as implantation bleeding happens: while your body takes care of avoiding menstruation through a series of signals, and as the help of HGC; the blastocyst causes bleeding that is normally small, by wearing away the tissue that lines the endometrium (very sensitive at the moment, and irrigated with the blood vessels that will nourish the new being). This bleeding is usually darker than menstrual blood, and sometimes it is no more than a couple of drops, so do not panic if it presents these characteristics.

You have just seen a video that can clarify some doubts. There is a long way to go, but do you realize the great quantitative advance that has occurred in a few days? From fertilization between two cells we pass to an organism made up of three layers that begins to nourish itself; but also the placenta, the amniotic sac, and the mucous plug are developed, to avoid infections and protect what will be your baby.

We invite you to continue with us this series about pregnancy. Enjoy it!

First image and video - Implantation in Primitive Streak