1ST WEEK OF PREGNANCY
The week of pregnancy is calculated according to the first day of the last menstrual period (SAT). Ovulation occurs on the 14th day of the menstrual cycle. Fertilization takes place after this day. Pregnancy detection occurs after the 4th week of pregnancy, with the embryo settling in the uterus and the rise of BHCG in the blood. For this reason, it cannot be said that there is a pregnancy before 4 weeks.
2ND WEEK OF PREGNANCY
According to the last menstrual date, ovulation and fertilization are not yet possible in the 2nd week. . No pregnancy yet. A selected egg in the ovary is getting ready to hatch.
THREE WEEK OF PREGNANCY
Ovulation took place on the 14th day from the beginning of the week, that is, according to the last menstrual period, and the egg is waiting to be fertilized in the tube.
The sperm head consists of a nucleus and a structure called acrosome, which contains proteolytic enzymes surrounding this nucleus. When the sperm reaches the vagina, many of them die. The number of sperm that passes through the cervix and reaches the tube only is about 1000. In humans, the mucus of the cervix (cervical mucus) serves as a reservoir for sperm. If the sperm arriving in the tube does not fertilize, it does not wait in the tube, it passes into the peritoneum (abdominal lining) and loses its effect.
Sperm must undergo some changes in order to achieve fertilization. This is called capacitation. The acrosome around it disintegrates and gains the ability to bind to the egg and move faster.
The egg (Oocyte) is captured by the tube after ovulation and is transported to the region of the tube called the ampulla. The egg stays in this area for about 80 hours, and as it matures, the inner lining of the uterus, which we call endometrium, acquires some features to accept the embryo that will be formed.
The egg (oocyte) has the ability to fertilize for 24 hours, and the sperm for 48-72 hours. However, fertilization can also occur within a total of 8 days, 5 days before and 3 days after ovulation. When sperm enters the egg, a situation called shingles reaction occurs. This prevents different sperm from entering the egg.
3 days after ovulation, the embryo is in the 8-cell morula stage. During this period, the embryo reaches the uterine cavity.
During the 1-3 day period, the embryo gains the ability to attach to the uterus by hatching (zona pellucida disappears).
The answer to the question "Am I pregnant at 3 weeks of gestation" is still no. Pregnancy tests are negative.
4TH WEEK OF PREGNANCY
The embryo that reaches the uterus in this week attaches to the uterine wall and begins to develop.
Endometrial (uterine wall) receptivity, that is, the ability to hold the embryo, is 21-28. It is high between days. This period is called the "Implantation window".
The increase in progesterone hormone makes some changes in the endometrium, allowing the embryo to attach.
Early pregnancy factor (EGF) reaches a level that can be measured in the blood 1-2 days after fertilization. EGF is secreted from the ovary before implantation (the attachment of the embryo to the endometrium), and then by the embryo itself. Its function is to suppress immunity (immunosuppression) and increase cell division.
Before implantation, the embryo secretes HCG 3 days after fertilization. Before HCG is detected in the maternal blood, it is detected by the corpus luteum in the ovary and increases estrogen and progesterone hormone secretion. HCG is detected in the embryo on the 18th day of menstruation and in the mother's blood on the 21st day of menstruation.
At 4 weeks, that is, 7 days after fertilization, the embryo attaches to the uterine wall in the blastocyst stage. It first penetrates the epithelium and then the circulatory system. Embryo attachment occurs mostly in the upper, back and midline of the endometrium. Lack of integrin in the environment during the implantation window may cause infertility. “Integrin” is the key factor in implantation.
Fetal fibronectin also plays an important role in adhesion. The placenta forms in this week. The placenta is formed when embryonal cytotrophoblast cells invade the mother's blood vessels. 1/3 of the uterine muscle layer is replaced by placental cells.
The placenta provides the synthesis of some hormones and substances necessary for the development of the baby in the future and the passage of nutrients and electrolytes. There is no direct contact between the maternal (mother) and baby circulation. For this reason, the human placenta is called hemochorial.
THE 5TH WEEK IN PREGNANCY
At the end of this week, your baby's first heartbeat begins.
Heart. The valves begin to function fully. This indicates that your baby's body development has begun.
The umbilical cord that connects your baby to life is formed in this week. This cord ensures the passage of nutrients and oxygen from the mother to the baby.
The lungs and brain form.
The arms and legs begin to form, although they are not fully evident.
PREGNANT. 6TH WEEK IN LIFE
Arm and leg joints grow longer.
The brain develops.
The retina, the center of vision in the eye, becomes evident.
The nose fits into place and the nostrils become clear.
With ultrasound performed vaginally, heartbeats can be easily seen and heard. Heartbeats can be seen with abdominal ultrasound after 1 week.
Insulin production begins. This is necessary for your baby's body functions to grow.
7TH WEEK OF PREGNANCY
Your baby is now 1 cm tall and his heartbeat can be easily monitored with abdominal ultrasound.
Its weight is approximately 0.8 grams.
Arms and legs begin to appear like short fins.
The heart, lungs and intestines continue to develop.
Arm. and legs begin to form, but just like the formation of a bud.
The lymphatic system begins to form.
8TH WEEK OF PREGNANCY
20% of your pregnancy is completed.
Your baby is growing. You may be able to see your baby's movements with ultrasound.
Height is 1.6 cm and weight is 1 gram.
The average height and weight we give each week varies for each baby. Your baby may be larger than normal or smaller than normal. Don't leave any question marks in your mind about this.
This week, bones begin to take shape.
The basic structure of the eye forms.
Language begins to develop.
Webbed and short toes and heels begin to appear.
THE 9TH WEEK OF PREGNANCY
Even though your baby is very small, he starts to move this week.
p>The average height is 2.3 cm and the average weight is 2 grams.
Many joints are formed.
THE 10TH WEEK OF PREGNANCY
One quarter of your pregnancy is complete.
The average height is 3.1 cm and the average weight is 4 grams.
The most important phase of the development period has ended. Now a period of very rapid growth begins.
The head length is around 1.5 cm, that is, half of its body length. This size is important for brain development.
Eye color becomes clear. The eyelids become active, the iris begins to develop.
The placenta begins to function. (It may extend to the next week) The placenta provides the necessary nutrients and oxygen for the baby. ar.
11TH WEEK IN PREGNANCY
Almost all structures have started to form and function.
Height is 4.1 cm on average, weight is on average. It is 7 grams.
The fingers and the heel are separated.
Hair and nails begin to grow.
Sex organs begin to form. There are only a few weeks left until you learn the gender of your baby.
Amniotic fluid, which usually consists of water and acts as a cushion, begins to accumulate this week.
The kidneys begin to work.
11 to 14. You should have the Down syndrome screening test (double test) during the week.
THE 12TH WEEK OF PREGNANCY
The average height is 5.4 cm and the average weight is 14 grams.
>Vocal cords begin to take shape.
The ear finds its place and settles.
The intestines find their place in the body and settle.
The liver begins to work. It is of great importance in cleaning the blood and storing nutrients.
The pancreas produces insulin. This is very important for your baby's growth.
Nuchal translucency is measured. This measurement is evaluated together with the double test. This measurement gives important information about possible problems.
You should have the double test, which is a down syndrome screening test, within 11 to 14 weeks.
13TH WEEK OF PREGNANCY
The average height is 7.4 cm and the average weight is 23 grams.
The eyes and ears continue to develop.
Ultrasound shows that the baby is moving inwards and outwards.
The neck grows longer.
Jaw placement is completed.
All nutrients will now begin to be taken from the placenta.
Your baby learns to make a fist. He starts to use his hands better.
You should have the double test, which is a Down syndrome screening test, within 11 to 14 weeks.
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