The first stage of prenatal development in the first trimester

For pregnant women, monitoring fetal development will bring its own benefits. One of them is to be able to measure the normal evolution of the fetus over time. For reference, the following provides an overview of fetal development in the first trimester.

Weeks 1 and 2: Preparation

Conception (the event of an egg meeting with sperm) usually occurs about two weeks after the start of the last menstrual period. That is, during the first two weeks of pregnancy, you are not really pregnant, but have entered the pregnancy preparation phase.

Week 3: Fertilizing

During this period, there was a union of spermatozoa and eggs in one of the fallopian tubes to form a zygote. After fertilization, the zygote will descend into the fallopian tubes to the uterus. Then he forms a group of cells called morula.

Week 4: Implantation

Implantation is the process by which morula develops into a blastocyst and then implants into the lining of the uterus called the endometrium. In blastocysts, internal cell groups become embryos. While the outermost layer will form the placenta.

Week 5: Increased hormone levels

During this period, the levels of the HCG hormone produced by the blastocyst will increase dramatically. This shows that the ovaries have stopped releasing eggs, producing more estrogen and progesterone.

Increased levels of this hormone will stop the menstrual period and encourage the growth of the placenta, forming an oxygen-rich blood supply and nutrients to the fetus. Here, the embryo begins to have three layers:

Ectoderm: forms the outer layer of the skin, the central and peripheral nervous system, the baby's eyes and inner ear.
Mesoderm: serves as the basis for the baby's bones, muscles, kidneys and reproductive system.
Endoderm: where the baby's lungs, liver, pancreas, and intestines will develop.

Week 6: Closure of the neural tube

During this period, the neural tube along the baby's back will be closed. The brain and spinal cord will begin to grow. The heart and other organs also begin to form. The basic structure of the eyes and ears begin to develop. The baby's body starts to form the letter C.

Week 7: Baby's head grows

The development of the first trimester fetus continues with the growth of the baby's brain and face. The shape of the nose begins to appear and the retina begins to form. The initial development of the hands and feet occurs during this period. The inner ear also begins to develop.

Week 8: Train the baby's nose

At this gestational age, baby's fingers start to form. The shape of the baby's ears and eyes starts to become clearer. Upper lip and nose formed. Candidates for bones and neck start straight. During this time, the baby is about 11-14 millimeters (1/2 inch) in size.

Week 9: Baby's toes appear

Here you see the arms and elbows of the fetus. The fingers are visible, the eyelids are formed and the baby's head starts to swell. At the end of this week, babies are about 16-18 millimeters (3/4 inches) tall.

Week 10: Elbows begin to bend

During this period, the baby's head becomes more rounded. The fetus starts to bend its elbows.
Elongated fingers, eyelids and outer ears continue to grow. The umbilical cord is clearly visible.

Week 11: The baby's genitals develop

During this week, the baby's face widens, his eyes are far away, his eyelids are confused, his ear position is low and tooth buds appear. Red blood cells begin to form in the baby's liver. Eventually, the baby's external genitalia begin to turn into a penis or clitoris and labia majora.

Week 12: Nails begin to form

The development of the first trimester fetus ends with nail growth. The baby's face becomes lighter and the intestines begin to form. The baby is currently about 61 cm (2.5 inches) tall and weighs about 14 grams (0.5 ounces).

Following the development of the fetus in the first trimester is of course attractive to pregnant women. By understanding the explanation above, you can anticipate and recognize changes that occur in your baby from time to time. Do not forget to check your pregnancy regularly with your obstetrician so that the development and health of the mother and baby can always be maintained.