What happens during the 1st trimester of pregnancy? Blood circulation, growth of arms and legs—your baby's development has begun!
The First Month of Pregnancy
The Baby: The egg implants in the uterus 7 days after fertilization, migrating from the ovaries to the uterus. By the end of the second week of pregnancy, it's no longer called a fertilized egg but an embryo, measuring just a tiny millimeter. The embryo at 4 weeks of pregnancy is in full development. The head and heart are already in place and will continue to develop. The placenta and umbilical cord facilitate the exchange of fluids and nutrients. Amniotic fluid, which will physically protect the pregnancy, comes into play. Its volume will vary during pregnancy depending on the space available in the uterus.
By the 5th week of pregnancy, blood circulation begins to function. The heart and placenta develop and become more complex. During the 6th week, facial features start to appear: cheeks, chin, jaws, etc. Many vital organs are also forming (kidneys, liver, lungs). The embryo is about 4 mm in length.
The Mother: It's a fleeting first month. Some women quickly sense that something is happening within them at the start of pregnancy, even before taking a pregnancy test. Others may not realize it but experience minor discomfort, fatigue, and weariness. It's an identifiable state they will refer to once their pregnancy is revealed. By the end of the 6th week of amenorrhea (SA), which is the 4th week of pregnancy (SG), you've crossed the milestone of the first month of your 1st trimester of pregnancy.
The Second Month of Pregnancy
Growth accelerates, the embryo becomes a fetus, and its size increases fivefold. For expectant mothers, it's time to adjust their lifestyle: balanced and safe diet, quitting smoking and alcohol, precautions when taking medication.
The Baby: During the 7th and 8th weeks of amenorrhea (5th and 6th weeks of pregnancy), the arms and legs start to grow. The head enlarges significantly, and the brain is forming. By the 9th week, the embryo becomes a fetus, about 23 mm long, with a recognizable human shape. Limbs elongate alongside the body, and hands and feet start to divide into fingers.
By the 10th week, the head is still disproportionate to the rest of the body. The eyes (closed) are in place, and well-formed eyelids protect them. At the end of the 2nd month, the length varies between 2.5 cm and 3 cm, with a weight of around 2.5 g.
The Mother: Your pregnancy is not yet visible, although your body is changing. You often experience fatigue, real moments of exhaustion that prompt you to go to bed early or opt for a restorative nap. Some pregnant women experience nausea, vomiting, and leg heaviness. However, there are no hard and fast rules. Each pregnancy is experienced differently. Physically, without having gained weight, you may find your clothes tight, your breasts swollen and possibly painful. Some tension may occur in the uterus as it develops and presses on the bladder, leading to frequent urination.
The Third Month of Pregnancy
This is the month of the first ultrasound, where future parents can visually and frequently concretely realize the pregnancy. After this first ultrasound, you need to send the pregnancy declaration to the primary health insurance fund (CPAM) and the family allowance fund (CAF) before the end of the 3rd month of pregnancy.
The Baby: By the 11th week of amenorrhea, the skin gradually covers the body. Nails start to form on the fingers and toes. During medical examinations, your doctor will let you hear the fetal heartbeats using a Doppler device. From the 12th to the 14th week, organ and skeletal structuring is finalized. All organs are in place and begin to function, although they need further maturation and sophistication. The kidneys are already functioning, and the fetus excretes urine into the amniotic fluid. Finally, the fetus can open and close its mouth, swallowing amniotic fluid. At 3 months of pregnancy, the length fluctuates between 8 and 11 cm, and the weight is around 60 g.
The Mother: At 3 months of pregnancy, you start to show a small protruding belly. For your comfort, choose suitable clothes that will adapt throughout your pregnancy. Sometimes the areola and skin of your breasts darken, and a dark line may appear on your belly. Finally, nausea and vomiting, for those who experienced them, tend to disappear at the end of your 1st trimester of pregnancy, allowing you to approach the 2nd trimester calmly and in better shape.