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Pregnancy Topics..

You are here : home > Pregnancy > Week-by-Week Fetal Development > Embryo is Implanted

Week 4: Embryo is Implanted

Week 4: Embryo is Implanted

The actual confirmation of pregnancy happens after the completion of 4th week with blastocyst implantation. Know more about your way to motherhood and the appearance of first signs of pregnancy.

Congratulations for completing your first month of pregnancy! In the 4th week, your fertilised egg begins to divide and float in your uterus. Once the fertilisation is complete, it shall be determined whether it is a girl or a boy. It certainly depends on the sperm whether it shall be a girl or a boy. Your partner's sperm may either carry an X chromosome or girl or a Y chromosome or boy. So, it is very much predetermined by the sperm chromosome of your partner.

Cells have all the genetic details that are required to become a child. Your baby starts forming from the single fertilized egg and the cells start dividing very fast. A total of 46 chromosomes shall predetermine the physical characteristics of your baby.

The egg fertilised is dividing rapidly and floats down the fallopian tube towards the uterus. Embryo moves inside your uterus around 80 hours from ovulation. The process of implantation starts after 3 days. Once it reaches the uterus, the egg fertilised shelters itself into your uterus lining.

What Happens in Week 4?

In the week 4 the embryo is firmly implanted in the walls of the uterus as it continues to multiply and grow. The cells now begin to group together to form different structures and the outer layer of the embryo sends out little projections, like fingers trying to clutch the uterus lining in order to attach itself to its mother's blood vessels and form the beginning of the placenta. The outer layer also forms the umbilical cord as well as the membranes that protect the baby.

The inner layer is also simultaneously self-dividing into first two and then three layers that grow to form different parts of your baby's body.

By the last day of this week, the embryo is completely embedded in the lining of the uterus and can be identified by an experienced gynaecologist through an ultrasound scan.

Congratulations, you must have just missed your period and are probably in the process of confirming your pregnancy.

The Process of Implantation

The egg fertilised is known as blastocyst that contains around 60 cells. This fluid cluster is still growing rapidly.
  • Blastocyst implantation takes place around the 8th day of the development of the embryo.
  • The embryo that is developing is around an inch long. However, it is developing at a very rapid pace.
  • It can multiply to reproduce itself at any point of time from the 14th day of conception. This is how twins, who are identical, are born.
  • Placenta attaches itself to your uterine at the implantation site. Once implantation of blastocyst is complete, the human gonadotrophin hormone (hCG) shall be released to the blood stream.
  • Human gonadotrophin hormone (hCG) when detected in pregnancy tests, conform your pregnancy.
  • The HCG level shall start lowering, but its concentration shall increase to support physical signs of your pregnancy.
  • This is the time when you must follow your intuition that something is coming.

Early Pregnancy Symptoms

You might experience different taste in mouth or your breasts may feel strange, nausea, frequent urge to urinate, cramping, bleeding from vagina are other symptoms that you may come across. These can be taken as clues that your baby is developing inside. These are the first signs of pregnancy.

Secret behind Implantation Success

One of the reasons why conception is possible is that a mother's body does not reject implantation from the fertilised egg. The foreign cell groups or the blastocyst in your body is a normal response of your immune system to look for and destroy such cells. Apart from that the maternal immune cells are disabled by the corticotropin-releasing hormone and chemokine secretion.

After implantation is complete, a reaction called decidual reaction happens that offers favourable conditions for the embryo to grow and develop.

Secretion of cervical mucus plug is stimulated by estrogens. This acts in an antibacterial and mechanical way to protect the interiors of your uterus.

You may be able to see the yolk sac and the amniotic sac with an ultrasound in the 5 or 6th week of your pregnancy. Your baby develops inside the amniotic sac and the yolk sac gets attached to the digestive system of your baby. Ultrasound examinations confirm that implantation has been successful and that you are on your way to motherhood.

When is actual pregnancy confirmed? What happens during the 4th Week of pregnancy? What happens after conception? Discuss here.

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Pareena.8 years ago
Can the doctor confirm pregnancy without ultrasound scan?
Leenika.8 years ago
After how long does implantation take place?
Angma.8 years ago
Does implantation cause bleeding? If Embryo gets implanted, will i have bleeding?
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