This is a complete week by week milestone timeline of your baby in the first trimester of your pregnancy.
Have you received the wonderful news you were waiting for, already? If you are sure that you are going to welcome a new member to your family soon, you must be quite excited to know how they are growing. Let’s look at your pregnancy week by week to understand what’s happening.
Here is a list of everything that you need to know about the growth of your baby in the first trimester.
Let us tell you a fact: you are technically not pregnant in the first week. Surprised? Here’s why: the doctors calculate your gestational period from the date of your last menstrual period (LMP). Therefore, the date of conception is after a week or two from the date of your last menstrual cycle which means you are not pregnant yet. The date is helpful to count ahead 40 weeks to estimate your due date.
This is the week when you ovulate. In the second week, the ovary releases an egg into the fallopian tube. Fertilization occurs if and when a sperm, among a million, penetrates into the fallopian tube through your cervix within 12 to 24 hours of ovulation.
After the egg is fertilized, it travels downs towards the fallopian tube while dissecting itself into multiple cells known as a blastocyst. Once the egg enters the uterus, it burrows itself into the uterine lining, known as implantation.
The one cell entity formed after fertilization is called a zygote. In case of the formation of multiple entities or if the egg splits into two, you will have multiple zygotes and therefore, pregnancies.
If you are awarded the news of bearing twins, that can be either fraternal twins (when two separate eggs are fertilized by two different sperms) or identical twins (when one egg splits into two after fertilization)
Interestingly, your baby’s inherited genetic characteristics will also be determined by this stage. A zygote has 46 chromosomes; 23 from your partner and 23 from you. These chromosomes are the determinant factor of your little angel’s sex and physical traits.
Normally, this is the time when your next period would be due and thus, you shall get the joyous news of being pregnant.
While you are celebrating the beautiful moment, your little one is already developing inside your safe womb. The embryo splits into two parts to form the placenta which delivers nutrients and oxygen to your baby while the other part continues to develop into a fetus. At this point, s/he is the size of a poppy seed.
The development initiates by forming a neural tube which will turn into your baby’s brain, spinal cord and backbone.
Monitoring your pregnancy week by week is a good way to know how to go about looking after yourself. At this stage, remember to exercise caution as your baby is the most vulnerable.
Your little one is now the size of a sesame seed, growing quite fast. The tiny heart starts to beat, and the circulatory system is on its way to development from the middle layer of cells called the mesoderm. The top layer is called the ectoderm while the inner layer is called the endoderm.
The neural tube starts closing from which the brain and spinal cord develops. The heartbeat is more regular, and the eyes, nose, mouth and ears are starting to form.
The embryo is curved with a tail. The developing arms and legs would be visible in the ultrasound as small swellings.
This is when your baby’s tiny hands and feet start to develop. The brain is more complex now and nerve cells in the brain are growing at a faster pace. Dark depression demarcates the area where nostrils would develop, and the formation of the retina has already begun.
Your little one would resemble the size of a blueberry.
By the eighth week, your baby has webbed fingers and toes and their hands and legs are longer. The respiratory system has started to form with their lungs developing. The other physical features such as eyes, ears, nose etc. are becoming more distinct.
Your baby, by this time, will have the initiation of a few key organs like the reproductive organs, pancreas, gallbladder etc. The head is relatively larger and tucked towards the chest. They even have tiny taste buds in their mouth by now.
But the interesting part is, they weigh just about a fraction of an ounce and are the size of a grape!
As you progress through pregnancy week by week, the little one inside you has been growing and maturing. Now, it is time to call your baby a fetus rather than an embryo. It is week 10 already and your little one is growing at quite a pace. The brain is developing with 250,000 neurons every minute while the fingers and toes begin to separate. The jawbones, nostrils and upper lip have started to develop.
The heart beats faster and you can notice small, jerky movements on ultrasound.
This week, the face broadens, eyes are separated, and red blood cells begin to form in the baby’s liver. By the end of the week, the baby’s external genitalia start developing, the body gradually straightens, and fingernails start to form.
Want to know an interesting fact? Your little one can breathe underwater: they inhale and exhale amniotic fluid.
You are almost at the end of your first trimester now. Your baby’s face is more developed, and so are the organs. They will also move their body parts, but it is too early for you to feel.
Now you know what has been happening in the first trimester of your pregnancy week by week. Stay tuned, your little sweetheart will grow and mature in the coming weeks.
- Fun Fact: You are not really pregnant in the first week of pregnancy. Conception occurs only at the second or third week.
- Your baby’s physical traits would be decided from the moment the zygote forms.
- At the fourth week, when you discover that you are pregnant, your little one is already the size of a poppy seed.
- The neural tube develops into the brain, spinal cord and backbone and the heart starts to beat by the fifth week.
- The rest of the weeks are when your baby’s organs develop gradually.
- By the twelfth week, your little angel is developed and now, it is the time to grow and mature inside the womb.