Let's be clear: the first trimester of pregnancy is something else. Between the joy of discovering a new life forming inside us and the fear of suffering a miscarriage... These first weeks of pregnancy are a real whirlwind of emotions and physiological upheavals for the person experiencing them. But then, what really happens during these 13 important weeks of pregnancy? How does our baby develop in the first trimester? And above all, how do we know if everything is going well? We explain everything in this article. Let's go!
The first trimester of pregnancy: duration, symptoms and examinations
When does the first trimester of pregnancy start and end?
The first trimester of pregnancy begins on the first day of your last period and lasts until the 13th week of pregnancy. On the first day of your last period, really? Yes! This may seem surprising, but the start of a pregnancy is calculated in weeks of amenorrhea (WA). That is, from the start of your menstrual cycle. Even if technically, you are not yet pregnant at this time. And so it is only from the third week that pregnancy begins as we understand it: when the egg is fertilized.
This first trimester is extremely important in the adventure of your pregnancy. Because even if it is still invisible on the outside, it is THE moment when many major changes take place, both for you and for the future baby. This is when the embryo develops the fastest, and all its vital organs lay their "foundations".
What are the symptoms of the first trimester in pregnant women?
Who says "first trimester" also says a bunch of physiological symptoms... Not always very fun, but often a good sign. We decipher them for you.
- Morning Sickness: Causes and Solutions
Ah, morning sickness in pregnant women! It's often hard to escape, as it's one of the most common symptoms of the first trimester of pregnancy (up to 80%, according to the MSD Manual ). They're called morning sickness, but they can occur at any time of day. The cause? The body's rapid increase in the production of hCG. These pregnancy hormones can disrupt pregnant women's digestive balance and cause these unpleasant sensations.
To alleviate them, you can:
- split your meals;
- avoid fried, fatty or spicy foods;
- consume ginger;
- drink regularly (water!).
However, if the nausea becomes so severe that you are unable to eat, talk to your doctor promptly.
- Fatigue and pain: what is normal
Unsurprisingly, the first few months of pregnancy can be extremely tired—but that’s completely normal. Yes, your body is working hard to adapt to pregnancy. It therefore needs to consume a lot of energy to do so. And remember, the surge in your hormone production, such as progesterone, can cause a sedative effect that will tend to leave you feeling exhausted. Even after a good night’s sleep.
How to manage this? Simply by listening to your body. Rest whenever you can. And think about giving yourself a little nutritional boost by adopting a balanced diet. Or by taking a course of pregnancy food supplements to boost your energy levels!
Some pain is also common, such as pain in the lower abdomen and breasts. Your uterus is stretching, your body is preparing for breastfeeding. If it remains bothersome, know that it is generally harmless. However, if it becomes too intense or is accompanied by gynecological bleeding , consult your doctor without delay.
- Other common symptoms
Wondering when pregnancy cravings start ? Well, sometimes as early as the first week of pregnancy! But you might experience other common symptoms like:
- disgust for certain foods;
- aversions to certain odors;
- acne ;
- breast hypersensitivity;
- frequent urge to pee.
We grant you, all these symptoms are not always easy to live with for the mother-to-be. But they are positive signs that show that your pregnancy is progressing normally. Stay tuned, be patient: all this is only temporary, we promise.
How do I know if my pregnancy is going well in the first trimester?
When you're a mom-to-be, you want to say out loud " I'm pregnant !" to everyone. But you're also afraid of what might happen to you. You want everything to go well, and that's normal! Fortunately, there are plenty of tests in place to reassure you:
- A first blood test to check that you are not carrying diseases that pose a risk to the pregnancy and the future baby.
- Fasting blood glucose for pregnant women with a history of gestational diabetes.
- A dating ultrasound around the 8th or 9th week of amenorrhea. You will receive the documents for your pregnancy declaration (to send to Social Security).
- The 1st trimester ultrasound, around 12 weeks of amenorrhea.
- Your monthly prenatal check-up to make sure everything is going smoothly.
- Screening for Down syndrome between the 11th and 13th week of amenorrhea. But only if you want it, because it is not mandatory, although 100% covered by Social Security.
How does the baby develop in the first trimester of pregnancy?
We tell you how your tiny baby is developing, week by week, during the first trimester of your pregnancy.
Week 1-4: Ovulation and Implantation
- Week 1: The beginning of 40 weeks of pregnancy
As you will have understood, the first week of pregnancy actually begins before you are even pregnant. Because the start of the countdown is the first day of your last period! Your body is preparing for possible fertilization, even though the egg has not yet been released.
- Week 2: Ovulation
Then ovulation finally happens. At the end of the second week, one of your ovaries releases an egg, which travels down the fallopian tube, ready to be fertilized.
- Week 3: Fertilization of the oocyte
Fertilization occurs during the third week, when the sperm penetrates the egg. The egg then divides into several cells, while continuing its little journey towards the uterus.
- Week 4: its implantation in the uterus
Then, at the end of the first month, comes implantation. The egg has become a blastocyst. It attaches to the uterine wall: this is nidation, an extremely important step for the future embryo.
Week 5 to 8: the first training sessions
- Week 5: Formation of the umbilical cord
In the fifth week, the embryo begins to take shape. The umbilical cord develops, and establishes this vital connection between the mother-to-be and her baby. It allows it to receive the oxygen and nutrients it needs.
- Week 6: Heart begins to beat
The 6th week, here we are: the embryo's heart begins to beat. Visible on ultrasound, this beat announces the beginning of blood circulation. The embryo measures approximately 5 millimeters and its main organs begin to form.
- Week 7: Brain Development
The cerebral cortex and cerebral hemispheres begin to form. The embryo measures about 10 millimeters, and shows the first signs of development of its nervous system.
- Week 8: First movements
The embryo begins to move. But, at 16 millimeters… You won't feel its movements yet! It weighs 1 g and its vital organs continue to develop (stomach, lungs and kidneys). Its face begins to take shape: its eyes, nostrils and lips appear.
Week 9 to 13: Accelerating Development
- Week 9: Fingers and toes appear
In the 9th week, his arms and legs are getting longer. Fingers and toes, initially resembling small buds, are slowly forming. An important step in your future baby's motor skills!
- Week 10: Increased heart rate
The fetus's heart is racing! It is now beating at about 170 beats per minute. This rapid rhythm supports the development of all the vital systems of the fetus, which is becoming more and more like a small baby.
- Week 11: Transition from embryo to fetus
At the 11th week, it is official: the embryo becomes a fetus. Its head is still large compared to the rest of the body, but it begins to straighten up and take shape. The facial features become clearer, its eyes are now in front, in their right place. It measures about 45 millimeters and weighs 10 grams.
- Week 12: Nail growth
During the 12th week, the fetus's nails begin to grow, as well as its eyelashes and hair. It measures 60 millimeters, and all its vital organs are now formed. They will continue to develop over the next few months.
- Week 13: Spine Training and Thumb Sucking
13th week, the last of the first trimester! The spine and ribs are forming. The fetus measures about 75 millimeters and weighs about 30 grams. Its bones are starting to harden, and it is also developing reflexes, like... thumb sucking. Yes, your baby sucks his thumb in your belly. Crazy, right?
You are now a future mother who knows everything about the first trimester of pregnancy! One thing is certain: it is a period full of changes. Both for you and for your baby. No time to be bored during these first weeks of life in utero! But with the support of those around you and the medical profession, you will lay the foundations for a peaceful and fulfilling pregnancy. We wish you the smoothest possible one.
