![pregnant asian woman looking at ultrasound scan](https://a.storyblok.com/f/94137/1440x1080/81bebe0a0e/pregnant-asian-woman-looking-at-ultrasound-scan.jpg/m/)
Your little one goes through so much in the span of 9 months, developing to be the bundle of joy you’ll have in your arms before you know it. Every stage of development in your pregnancy is important, and there’s quite a lot to digest as to what’s going on inside your womb.
Here, we talk about your child’s development in the first trimester, which happens from weeks 1 through 12:
Conception
![](https://a.storyblok.com/f/94137/600x400/1377039518/happy-asian-couple-holding-pregnancy-test.jpg/m/)
Pregnancy begins when a sperm fertilizes an egg. For most couples, they don’t usually know when fertilization occurred, so they base the due date on the first day of a woman’s last menstrual period (LMP.)
Your doctor counts forward 40 weeks from your LMP to estimate your baby’s due date, and you can expect the arrival of your little one to happen more or less between 38 to 42 weeks, which is when most births occur.
The Embryonic Stage
![](https://a.storyblok.com/f/94137/600x400/251c4ec5f1/embryo.jpg/m/)
After Conception, your baby will go through a period of dramatic change in the embryonic stage. This occurs between weeks 5 through 10, and your baby is what we call an embryo.
In this stage, the cells of the embryo, which are called embryonic stem cells, multiply and develop. They become the types of cells that make a whole human body. It is in this stage that your baby’s major organs and body parts begin to develop, like the heart, face, arms and legs, sexual organs, as well as your baby’s nervous system and muscles.
Another major development inside your womb is the formation of the placenta, which also happens in the embryonic stage. The placenta is responsible for taking all the nutrients, oxygen, and water from your blood to pass along to your baby through the umbilical cord. It also takes charge of removing your baby’s waste, and filters out most of the harmful substances that may be in your body.
Last but not least, the amniotic sac also forms during this stage. It is filled with amniotic fluid, which protects your baby in the uterus.
By week 10, your baby will be about an inch long, and is ready to go through the next stage: the fetal stage.
The Fetal Stage
![](https://a.storyblok.com/f/94137/600x400/957445df03/ultrasound-test.jpg/m/)
The fetal stage begins in week 11 and will occur until birth. Now, your baby is called a fetus, and will grow longer and gain weight quicker than they did when they were an embryo.
Through week 11 onwards, your little one will develop their organs and body parts, and their fingernails and toenails will begin to form. By the end of the first trimester, your little one’s kidneys have already started working, and their size has tripled in length to about 3 inches.
Caring for Mama
![](https://a.storyblok.com/f/94137/600x400/4a3df435ea/expecting-asian-couple.jpg/m/)
The first trimester is often known as the most turbulent trimester for mamas, as it’s a time filled with fluctuating moods, morning sickness, intense cravings, and being averse to certain food and scents.
While your baby develops in your womb, your body is going through a lot of changes too. It is important to visit your doctor soon after you find out you’re pregnant in order to get all the prenatal care you and your baby need.
TAGS:first-trimester