Baby Development in Womb During First 13 Weeks | First Trimester of Pregnancy

1 – 13 Weeks of Pregnancy : The First Trimester

In this article we will explore about the baby’s development in the first 13 weeks of the pregnancy. Now first 13 weeks is actually the first trimester of pregnancy that is the first, second and the third month of the pregnancy. While pregnancy is spanning approximately 40 weeks, we will try to cover Week 1 to week 13 of pregnancy in this article. So let us start with the first week of the pregnancy.

First Week of Pregnancy

So the initial first two weeks are technically not the part of your pregnancy. During this time the baby is not there in the womb and the conception has not happened. You would be astonished to know that the first week of the pregnancy is calculated from the first day of your last menstrual period. That is, the first day of your last menstrual period, the first week of the pregnancy starts.

Second Week of Pregnancy

When you will be in your second week of pregnancy, the ovulation will be there and the egg will be released from your ovary. So it is actually the second week of the pregnancy when the conception happens. As the egg is released from the ovary and it will travels in the fallopian tube, it will wait for the male sperm. When female and male makes relation, this female egg will meet male sperm. This union of female egg and male sperm is called fertilisation.

The fertilization will happen, so this is the very start of the baby formation.

Third Week of Pregnancy

Now let us understand what will happen in the third week of the pregnancy. In the third week, the fertilized egg will divide and it will form blastocyst. So there will be  two division of this fertilized egg, one will be called embryo and the other division will form a protective layer outside of the embryo.

Fourth Week of Pregnancy

Now by the end of the fourth week of the pregnancy, this embryo will implant itself in the uterine lining and this process is known as Implantation. So when the embryo falls in the uterus to get attached to the uterine lining, it will be accompanied with a slight bleeding and pain.

This is not every woman would see or feel, but this is usually seen when the implantation happens. So this is actually the time approximately one week before your probable period. It is a big and very early sign to understand that you are pregnant. If before approximately one week of your period date, you’re seeing this slight bleeding or cramp on your lower abdomen, it is probably the implantation bleeding. It is a big indication of the pregnancy.

5th to 10th of the pregnancy

Now let us understand what happens in the week 5th to 10th of the pregnancy. This is basically the period when the foundation will be built. This period is known as Embryonic Period . In this period, the essential organs like the spinal cord, heart and brain of the baby starts developing.

By the end of the fifth week or you can say between fifth to sixth week the baby’s heartbeat can be detected easily in the ultrasound scan.

This is the time when the placenta forms and from the placenta the embryo gets the required nutrients and the oxygen supply in the form of blood. This is a very important time because lots of organs are in formation and the pregnant woman would require a good rest. The baby’s major organs are taking the shape, so pregnant woman needs to be very careful in this period.

11th to 13th week of the pregnancy

Now let us understand what happens between the 11th to 13th week of the pregnancy. This period is known as the Fetal Transition Period because as we move into this fetal period from the foundation period  of the baby that is the 5th to 10th week of the pregnancy.

Now the embryo transforms into a fetus. So between 11th to 13th week, the fetus experience a rapid formation of the limbs, the legs and hands, fingers etc. By this time the facial feature of the baby are more defined. This time the baby will start moving very subtly, very slowly. Since the baby is very tiny, this movement will not be felt by the pregnant women.

By the end of the 13th week of the pregnancy, the baby inside the womb would be approximately 3 inches in length.

Also Read : Week 14 of Pregnancy- Baby Development and Pregnant Women

Symptoms of the First Trimester of Pregnancy

Now let us understand what noticeable changes will occur in the pregnant woman. So these are the symptoms of basically the first trimester of pregnancy. The prominent signs are morning sickness, vomiting, feeling low on energy, fatigue and the breast tenderness. The feeling of vomiting will be experienced by some of the pregnant women. So these are very normal during the pregnancy, there is nothing to worry about it. 

Some pregnant women may feel an aversion towards the food. Disliking or the liking towards the food and the food habits would change now.

Due to the productions of so many hormones in your body like progesterone, estrogen and HCG hormones, there will be behavioural as well as the physical changes that you will notice.

Try to cope up with all of them because they are quite normal. Stick to a balanced diet. By this time you would have visited your gynaecologist and abiding by the diet plan they have prescribed to you.

Read : Week 15 of Pregnancy – Mother and Baby

So this is all about the first 13 weeks of the pregnancy. What happens with the baby, from the conception till the baby reaches 13 week inside the womb. If you found this article interesting and worth reading, kindly share it for a broader reach. Consider subscribing garbhgyan.com for more such pregnancy tips and information. Stay Happy | Stay Healthy