The first week of the first month of pregnancy

Week 1

Pregnancy begins on the date of fertilization averaging fifteen days after the first day of last menstrual period (for 28-day cycles)

The first week of pregnancy corresponds to the third week of gestation, that is to say there are no rules. While fertilization begins, the body of the mother, who has not yet physical signs, is preparing to welcome the unborn baby

First days of pregnancy: unperceived changes

Even if fertilization has occurred and you are pregnant, you will present almost no change during the first week of pregnancy

Looking good, you may notice a significant increase in breast size. But it is mainly in the uterus that everything happens

 After fertilization of the ovum by the sperm, the egg will be divided into identical cells becoming smaller called blastomeres. The 16-cell stage, about three days after fertilization, the embryo takes the form of a small ripe, called morula

This will then route through the fallopian tube

 An anomaly at this stage of segmentation can lead to a twin pregnancy

First week of pregnancy the uterus prepares to host egg

While the egg continues its journey to the uterus, it turns and prepares to host the egg must attach to its walls

It is progesterone secreted by the corpus luteum (which is formed during the second part of the cycle and disappears when the placenta is autonomous), which helps prepare the uterine lining for implantation and block uterine contractions

The uterus and prepares to receive the embryo

 Morula, then comprising 30 blastomeres through the 10 cm which separate it from the uterine cavity in four days

The embryo is then enriched nuclear material (DNA) and blastocyst becomes the 5th day. At the center of it will form the embryonic disc and peripheral cells, which constitute eventually the placenta

The embryo will remain open for 48 hours in the cavity of the uterus, nourished by the secretions of the endometrium

If the yellow body is not functional, the embryo may die before implantation

The egg, measuring just 0.1 mm, will implant in the uterus at the beginning of the second week