Week 3 of Pregnancy: All You Need to Know

After going down the entire length of the fallopian tube, the fertilized egg reaches your uterus and will implant itself into the uterine lining to become an embryo. The embryo then turns into both the fetus, from embryoblast cells, and placenta, from the trophoblast cells, which will provide nourishment and energy for your baby in the next few months.

The embryo then develops into the fetus and placenta and will carry the baby until it is fully-formed at around 9 months.

How is my baby growing?

Pregnancy is often divided into trimesters or segments of three months. By the third week, you are in the first month of your first trimester. As mentioned, your baby at this point is a blastocyst traveling down your fallopian tube towards your uterus or has implanted itself into the uterine lining.

People often do not particularly “feel” pregnant in the first month or so, and this is because the blastocyst takes about a week to travel the whole length of the fallopian tube and implant itself into the uterine wall. It will take a few more weeks for the baby to grow enough for it to be noticed. Hence, in week 3 of pregnancy baby development, people neither “look” nor “feel” pregnant just yet.

Your Doctor Visits

Baby Development

If you are reading this, it is likely that you are expecting to become a parent soon, so congratulations! These are exciting times and it may come with some feelings of being overwhelming. On week 3 of pregnancy baby development, it is normal for people to still be unsure of their pregnancy. After all, nothing about the pregnancy up to this stage is manifested physically or made obvious just yet.

Before we get into what occurs on week 3 of pregnancy baby development, let us have a quick review of pregnancy and the terms involved.

How does one get pregnant?

Once the sperm reaches the egg and fertilizes it, the zygote is created. The zygote, a single cell, then splits into 16 cells at which stage it is called the morula. As it travels down the fallopian tube, it continues splitting until it is shy of just a hundred cells. At this phase, this cluster of cells is called the blastocyst. This is what occurs on week 3 of pregnancy baby development.

After going down the entire length of the fallopian tube, the fertilized egg reaches your uterus and will implant itself into the uterine lining to become an embryo. The embryo then turns into both the fetus, from embryoblast cells, and placenta, from the trophoblast cells, which will provide nourishment and energy for your baby in the next few months.

The embryo then develops into the fetus and placenta and will carry the baby until it is fully-formed at around 9 months.

How is my baby growing?

Pregnancy is often divided into trimesters or segments of three months. By the third week, you are in the first month of your first trimester. As mentioned, your baby at this point is a blastocyst traveling down your fallopian tube towards your uterus or has implanted itself into the uterine lining.

People often do not particularly “feel’ pregnant in the first month or so, and this is because the blastocyst takes about a week to travel the whole length of the fallopian tube and implant itself into the uterine wall. It will take a few more weeks for the baby to grow enough for it to be noticed. Hence, in week 3 of pregnancy baby development, people neither “look’ nor “feel’ pregnant just yet.

Body & Life Changes

How is my body changing?

At week 3 of pregnancy, baby development, the body prepares itself for pregnancy. The body prepares the uterine for the arrival of the blastocyst or copes with the recent implantation of it. However, even before the blastocyst is formed, preparation has already taken place. 

Upon the release of the egg, before fertilization, the corpus luteum, an endocrine structure, produces hormones related to pregnancy including estrogen and progesterone. These hormones are responsible for the symptoms we commonly associate with pregnancy, or even premenstrual syndrome, like morning sickness and cravings. 

The corpus luteum will provide the baby all the nourishment and protection it needs up until the placenta takes over by the second trimester. Because the blastocyst has only spent a week at maximum implanted in the uterine lining, the concentration of these hormones are not nearly high enough for intense pregnancy symptoms, but can still manifest at this point of the pregnancy.

What should I be concerned about?

The symptoms that may show up are mild, but would probably carry on for the entirety of the first trimester, or even the entire duration of the pregnancy. 

These symptoms include light cramping or pressure on the lower abdomen that might feel like some version of menstrual cramps. This is no reason to panic because this can be caused by the implantation that takes place as the blastocyst implants itself into the uterine lining. If anything, having this pressure or light cramping is a good sign that things are going as expected in the pregnancy. 

Due to the hormones being produced by the corpus luteum, you may also develop as well a more sensitive sense of smell. This makes it easier for pregnant people to pick up certain scents throughout the pregnancy and may end up making morning sickness worse. Because of this, it is best to veer away from unpleasant or strong odors for the time being.

Not only is the sense of smell affected, but also the sense of taste, with many women reporting a metallic taste in their mouth. This is a normal and common symptom that shows up early in week 3 of pregnancy baby development. This is due to the onset of hormones being produced, so it should not cause panic for expectant mothers.

Your Doctor Visits

What should I tell my doctor?

Week 3 of pregnancy baby development is one of the more pleasant parts of your pregnancy, as you have yet to develop and experience some of the more uncomfortable symptoms of pregnancy such as morning sickness. Consult your doctor for anything you may find worrisome.

Health & Safety

What should I know about being healthy and safe while pregnant?

As always, it is best to eat healthily and watch your physical activity in order to be in the best state of health, ensuring a safe pregnancy for you and the baby. 

Hello Health Group does not offer any advice, diagnosis or medical treatment.