A normal pregnancy lasts for 40 weeks. The first three months (12 weeks) of this period are known as the first trimester. It’s the most crucial stage of pregnancy because the fetus develops rapidly in these first few weeks. During the first trimester, the baby’s neural plate forms, and his/her body organs start to develop.
Also, this is the time when you’ll experience different pregnancy symptoms. While these symptoms may seem annoying, they are important for fetal development. During the first trimester, fetal growth is quite predictable. Let us walk you through the weekly growth of your baby in the first three months of pregnancy.
The first trimester is the period when your baby will grow into a fetus from a small grouping of cells. It starts from the first day of your last period, but conception only occurs two weeks after the last menstrual period. This means you might not even know you’re pregnant for the first two weeks.
Once the conception occurs, the fertilized egg will transfer from the fallopian tubes towards the uterus. During this period, the placenta will also form inside the uterus. Placenta is an important pregnancy organ that’s responsible for supplying nutrients to the baby.
This is the period when your baby will grow into a fetus from a small grouping of cells. Heart, brain, and spinal cord are the first three organs that’ll develop completely by the end of three months. The baby’s heartbeat will increase and reach up to 110 beats/minute after 4th week of gestation.
A point to Remember - During the first trimester, the fetus is susceptible to damage from external sources. That’s why you should immediately quit alcohol and smoking as soon as you get the news of pregnancy..- HERA
Fetal development occurs in three stages during the first trimester.
Germinal stage begins as soon as conception occurs. The egg & sperm meet, which triggers fertilization in one of the fallopian tubes. The fertilized egg, known as the zygote, then moves towards the uterus.
After one day of conception, the zygote starts to divide (due to mitosis) and form multiple cells. During this time, the outer cell wall separates from the zygote and forms Placenta. Implantation occurs by the end of the germinal stage, which triggers hormone imbalance in the body.
This is when the majority of women take a pregnancy test and get the good news.
Embryonic stage begins three weeks after conception and continues till the seventh week of pregnancy. During this time, the group of cells grow further and develop distinct human features. This is the time when Embryo develops the neural tube [3], which further develops into the central nervous system over the course of next two weeks.
During the sixth week of gestation, facial features like nose, eyes, and ears form as well. The heart also develops and the heartbeat starts to increase gradually. By the end of embryonic stage, i.e., eighth week of pregnancy, all the major organs get fully developed. But, the embryo is still pretty small in size and only weighs about one gram.
After the eighth week, the embryo turns into a fetus and enters the fetal stage. This stage continues till birth and the mother-to-be starts experiencing many fetal movements. During the fetal stage, the baby’s sex organs also develop. Sex organs are the last to develop in a fetus. But their size continues to grow throughout the pregnancy. After the 12th week (3 months), your doctor may also be able to determine the sex of the baby [4] using special tests.
Now, let’s take a look at a few fetal development benchmarks that indicate a healthy pregnancy.
As we mentioned earlier, many women don’t know they’re pregnant for the first two weeks. But, the body still experiences many changes to create a healthy environment for babies. Let’s discuss the weekly growth of your little one during the first month of pregnancy.
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The third month of pregnancy is officially the last month of the first trimester. By the end of this month, all body organs will be in their place and continue to grow for the remaining period of gestation.
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The first trimester is also crucial for the mother. This is when the so-called “pregnancy symptoms” will kick-in. You’ll also put on some weight during this period. Here are some additional physical and emotional changes that you’ll experience during the first trimester.
Hera Pro Tip: Bleeding is also one of the symptoms of early pregnancy. But, if it becomes severe, you should immediately visit a doctor..- HERA
The first trimester of pregnancy is crucial for both the mother and the baby. As soon as you get the news of your pregnancy, you should instantly book a prenatal care appointment with your OB/Gyn. He/she’ll do the initial scanning and also prescribe prenatal vitamins so that you can enjoy healthy pregnancy.