Pregnancy Bliss | Reproductive Health Answers
Millions of sperm make the journey. Only one of them gets to fertilise the egg.
Conception
How does natural conception take place?
Most women know that at ejaculation, a man deposits millions of spermatozoa into the vagina. The vast majority of these will not make it past the womb. Only a few thousand get to where the egg. (ovum) is, which is usually at the outer end of one of the tubes. Only one of these will actually fertilize the egg. The sperm and egg fuse to form one cell, called a zygote. This cell will undergo incredible changes in the ensuing days, resulting in a mature baby about forty weeks later.
What happens soon after fertilization?
Things are happening quietly. There is absolutely no way for a woman to tell immediately whether a sexual act has resulted in conception. All those popular novels in which a woman says that "I knew immediately after, that I had conceived" are sheer fantasy.
Within thirty hours of fertilization, the fertilized egg undergoes the first division to form two cells. This is only the beginning of billions of divisions and changes that will take place within the first few weeks of pregnancy.
The dividing ball of cells - which is still quite tiny in size - is, meanwhile, being swept steadily along the tube towards the cavity of the womb, where it will implant.
When does implantation take place?
After the tubal journey, lasting four to five days, the ball of cells, now numbering fifty to sixty, reaches the uterine cavity. Implantation commences around seven days after fertilization and is complete by day fourteen.
Does any sign or symptom herald implantation?
In most cases, no. In a few cases,, there may be light vaginal bleeding. Since this occurs about three weeks or so after the last period - and the woman is still unaware of her pregnancy - this light bleeding may be mistaken for a menstrual period. It has been known to cause confusion in dating the pregnancy. However, this problem is easily sorted out using ultrasound scan, provided the woman books for antenatal care within the first half of the pregnancy (which is the norm).
What happens after the embryo has implanted?
The serious business of turning this mass of cells into a human being starts then. Even though it is still tiny in size, organs start forming at three weeks and their formation is complete by eight weeks.
From that point, only maturation and increase in size is taking place.
Even though the fetus is only about 2.3 cm in length (less than one inch) at eight weeks, the nose, ears, finger- and toebuds are already formed.
The absolute sensitivity of this period cannot be overemphasized. Any chemical insults - for example, in the form of drugs taken - during this particular period are likely to have the most profound effect on the fetus.
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