First trimester (first 3 months)
First of all, congratulations. You’re pregnant and expecting a baby. Definitely, you wonder how your baby grows and develops. Here, we will tell you how your baby is developing in the first three months in your uterus. What your baby looks like? What are the sizes? When will the heartbeat start? You will find answers to all your questions here.
1.week (preparation period)
It will sound a bit strange, but you are not really pregnant in the first two weeks of pregnancy. Yes, you didn’t read wrong. Pregnancy starts 2 weeks after your menstrual bleeding. Your doctor will count 40 weeks after your last menstrual cycle when calculating the birthdate. This period also covers the period in which you are not pregnant.
The sperm and ovum cells form a single-cell structure called zygote in the uterine tubes. If there were more than one ovum and fertilization occurred, more than one zygote may develop. The zygote has total of 46 chromosomes, 23 from the mother and 23 from the father. These chromosomes contain the genetic structure that will determine sex, eye color, hair color, height, weight and face shape of your baby. In addition, there is a genetic structure that will determine the characteristics of intelligence and personality. After fertilization, the zygote moves from the uterine tubes down to your uterus. During this movement, the cells continue to divide rapidly and become a small cell cluster reminding raspberry. The inner cells will form the embryo, while the external cells will form the membranes which will do the feeding and protection.
The zygote is called as blastocyst when it reaches approximately 500 cells. The blastocyst reaching the uterus implants to the uterine wall to be fed. Thus, the placenta starts to be formed to feed your baby during your pregnancy. At the end of this week, the pregnancy test becomes positive.
4.week (embryo period)
The embryo period begins in the fourth week. Now your baby’s brain, spinal cord, heart and other organs start to be formed in about a millimeter in size. The embryo consists of three layers. The outer layer called as ectoderm forms the neural tube, i.e. the part that will develop your baby’s brain, spinal cord, nerves and spine. The middle layer called as mesoderm forms the heart and the blood vessels of your baby to provide blood circulation as well as muscle, bone, kidney and reproductive organs. The innert layer called as endoderm forms the lung, intestine and bladder.
The height of your baby is a few millimeters, i.e. the tip of a ballpoint pen. Your baby’s heart and vascular system are formed in this week, its heart stars to beat. Even if you cannot hear it, the heartbeat will be detected by ultrasound examination. Thus, the circulatory system is the first working system of your baby.
Growth is accelerating in this week. The neural tube extending along the back of your baby closes and the heart beats at a regular rhythm. The shape of its face begins to appear and the openings for mouth and inner ear are created. Respiratory and digestive systems begin to develop. The middle tissues will form connective tissue, ribs and muscles. The arms and legs wil be developed from the small protrusions on both sides.
The height of your baby has reached 8 millimeters, is slightly larger than the pencil eraser and its weight is less than an aspirin. The umbilical cord between the placenta and your baby now can be seen more clearly. The brain begins to form and the skull is still transparent. The protrusion of the arm is growing a bit more. Your baby’s face becomes a little more pronounced. Now mouth, ear and nostrils can be seen more clearly.
Your baby’s fingers and toes begin to form. The elbows and wrists become visible. The eyelids begin to be formed. The ears, the upper lip and the nose can be seen more clearly and the height reaches to 1 -1.5 cm. Now your baby’s heart is very advanced and beats 150 times per minute, ie twice as fast as a normal adult.
The height of your baby is 2.5 cm and its weight is 3.5 grams. The extension in the tail cavity is gradually decreased and its appearance is now starting to resemble a human. Its head leaning towards his chest forms half of its whole body. Its nipples and hair roots begin to form. The pancreas and gall bladder take their places. Testes or ovary begin to develop. By this week, your baby can begin to move but you will not feel it exactly.
From this week on, your baby’s organs can be seen more clearly. The embryonic tail disappear completely. Fingers and toes are completely separated. Skeletal bones start to be formed. Also by this week, your baby’s brain starts to produce 250,000 new nerve cells per minute. The eyelids are no longer transparent and their ears begin to take shape. Dental roots start to be formed. If your baby is a male, his testicle starts to produce the male hormone testosterone.
At the end of this week, your baby’s external genital organs can be seen more clearly. The sex of your baby is now visible. By this week until the 20th week, your baby’s weight will increase by 30 times and its length will increase by 3 times. This will result in the growth and increase of the veins in the placenta to supply sufficient nutrients for your baby.
Your baby is now called as fetus. Its length is about 7-8 cm, and its weight is 20-25 gr. Finger and toenails are formed. The jaw and ear are taking their final shape. First of all, if you choose a healthy lifestyle, this will positively affect your baby’s development. If you start this before you getting pregnant, it would be better.
Please carefully obey the following to-do and not-to-do list;
Get vitamins and folic acid supplements prescribed by your doctor.
Watch your weight. Do the exercises regularly recommended by your doctor.
Eat healthy. Pay attention to stress and other health problems .
Have your regular checks. Do not forget to tell your doctor about all the medicines you use.
Not- to -do:
Stay away from cigarettes and alcohol. Do not use drugs.
Your baby is growing and changing day by day. Do not forget to take care of yourself to give the best start to your baby.