3 Weeks Pregnant: Symptoms, Baby Development – What to Expect


The third week of expecting a baby is considered the official beginning of the wonderful time, the very start of pregnancy itself. Since ovulation mainly occurs right in the middle of the woman’s cycle, fertilization takes place approximately at the end of the 2nd week.

Thus, the 3rd week comprises conception and the first few days of the baby’s life within your belly. The actual pregnancy has already developed.

What Happens in the 3rd Week of Pregnancy?

  • For the first two weeks, your body was not pregnant: it was only preparing to conceive a baby. Now, fertilization might have occurred already. It means that an egg and sperm have connected and evolved into a single cell, a zygote. During this period:
  • The zygote cell starts its rapid growth: it divides repeatedly and doubles in size two times in 24 hours.
  • While growing in size, the zygote steadily moves along the fallopian tube to the uterus.
  • This is astounding, but the baby already has all the chromosomes that will determine her genetic background, having taken half of the genetic material from you and a half from her father.
  • The child’s gender is already known.

3 Week of Pregnancy: Early Signs and Symptoms

You might be anxious to know what is happening to your body: was the conception successful? What exact signs can prove that you are pregnant?

Here is the list of the most widespread symptoms of 3-week pregnancy:

  • dizziness;
  • sleepiness;
  • frequent urination;
  • loss of appetite;
  • light queasiness, especially in response to particular odors;
  • mild blood spotting.

While small amounts of vaginal blood are rarely dangerous, contact your doctor if they become worrisome. Still, many women experience mild spotting because their fertilized eggs have to burrow deep into the fragile lining of the uterus in order to the implant.

If you suffer from fatigue, drowsiness, or dizziness, it would be a good idea to minimize stress. Most pregnant women tend to sleep more. Following your body’s needs is of utter importance when you are expecting a baby, especially if only a few days have passed since conception. Catering to bodily needs ensures the baby’s safety inside your belly.

You can also notice that your basal temperature has risen slightly. This generally means a successful conception; the body starts producing more specific hormones of pregnancy (estrogen and progesterone). Most unwanted “side effects” of pregnancy appear due to this increase in hormone production.

The Size of Fetus in 3 Week Pregnancy

The zygote grows at an astounding pace; when it becomes a clutter of cells instead of a single autonomous one, it is called a blastocyst. After implantation into the uterus, the fetus looks like an empty ball of 250 cells, barely visible to the human eye. It sits in a tiny bag filled with amniotic fluid which serves to cushion the baby as she steadily grows larger.

The third week of pregnancy is the period when all basic organs and cords start developing. Even though right now the baby receives all the necessary nutrients and oxygen from the corpus luteum, the placenta has already begun burgeoning.

What Occurs During Fertilization?

Even though a woman can become pregnant at any moment of her cycle, the ovulation time is considered the best and the easiest period to conceive a baby. Fertilization is the second most important process which occurs after unprotected intercourse. The woman’s egg connects with one of the germ cells in her partner’s semen; as a result, a single cell is formed to carry combined genetic material from both parents. The zygote starts dividing even before it reaches the uterus, then it will implant into the woman’s womb and begin developing into a baby.

The zygote is the largest human cell; it can be formed only after successful fertilization. All 23 pairs of chromosomes are already contained within the zygote; your baby’s gender, facial features, eye and hair colors are already predetermined.

Has the Egg Been Fertilized?

Regular pregnancy tests fail to show if the egg has been fertilized. They are based on the evaluation of the HCG (human chorionic gonadotropin) level in urine. However, some time has to pass between fertilization and implantation for this specific hormone to rise in quantity. But some women desire to know at once if they have become pregnant; the scientists thus invented several methods of analyzing the changes in female bodies.

The fastest method to know if the egg has been fertilized is to conduct a test for EPF, early pregnancy factor. EPF is an immunosuppressive agent that fights the natural immune system’s response to alien cells within the organism. Male proteins presented by the germ cell are viewed as alien and therefore hostile; the immune system would try to destroy the fetus if not for the early pregnancy factor.

The immunosuppressant can be found in blood on the day after unprotected intercourse if fertilization has occurred, while HCG-based tests show adequate results only 8-10 days after conception.

When Does Ovulation Occur? Symptoms and Signs

Ovulation is the process of the matured egg being released from within one of your ovaries. Ovulation occurs 11 to 14 days after menstruation, though the exact period may vary according to individual particularities of your body. After maturation, the egg proceeds into one of the fallopian tubes leading to the uterus. Upon arrival it starts waiting for fertilization, namely for the connection with a man’s germ cell. If intercourse occurs during ovulation, it will most likely result in pregnancy.

Your partner’s semen can stay alive for up to six days, but the egg in the process of ovulation should be fertilized within 24 hours.

The rise of sexual drive (libido) remains the telltale symptom of ovulation: women start fancying attractive men with decidedly masculine features and traits.

How Many Days After Ovulation Does Implantation Occur?

Generally, it takes 2 to 3 days for the embryo to implant itself into the uterus. This process might be accompanied by mild blood spotting because the tender lining of the uterus is being slightly damaged so that the embryo could stay firmly in place. After implantation, the baby begins feeding off from her mother’s nutrients; this means that you will have to choose healthier food and drinks from now on.

The Role of Corpus Luteum in Early Pregnancy

Corpus luteum is a gland formed from the egg’s follicle. It produces luteal hormone progesterone which plays a major role during the entire period of pregnancy. Corpus luteum is responsible for supporting the fetus’s vital capacity up to 11-12 weeks so that it can receive sufficient nutrients and oxygen. Later in pregnancy, the functions of corpus luteum are taken on by the newly-formed placenta.

The Size of Corpus Luteum in Pregnancy

The size of the corpus luteum does not change much during pregnancy. For the first few days of its existence, the gland is some 15-20 mm in diameter; later, it grows only 10 mm more and remains like this up to 15th week of pregnancy. With the decline of its functions, corpus luteum gradually shrinks away.

Nutrition in the 3rd Week of Pregnancy

•Your nutrition is critical during all 40 weeks of pregnancy, but the early stages are the most important concerning the fetus’ central nervous system development. You might already take supplements with folic acid or prenatal multivitamins prescribed by your doctor. If not, consider consulting with a specialist on prenatal health or add more foods rich in folic acid into your everyday meals.
•Drink more fluids than usual: soon your body will be increasing the total amount of blood cells to cater to your growing baby’s needs so that fluids will be necessary for adequate fetal development. Clean water is the best choice; however, some doctors also recommend skim milk and fresh fruit juice.
•Try to decrease your consumption of caffeine; settle for decaffeinated beverages instead of coffee and tea.

Lifestyle in the 3rd Week of Pregnancy

  • Smoking or drinking alcohol is extremely dangerous for the growing baby. Quit the harmful habits for the sake of your child and family.
  • If your partner smokes, try to talk him out of the habit as well. Explain that inhaling cigarette smoke may lead to severe damage to the baby. Moreover, after birth cigarette smoke will remain one of your greatest adversaries because it is harmful to small children.
  • Get enough exercise but do not overexert yourself: stop when your body indicates exhaustion or even discomfort.
  • Review the medicines that you are taking regularly. Some of them, perhaps, will have to be replaced with safer medication.
  • Avoid stressful situations both at work and at home.
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