Successful Pregnancy
♫ Thursday, May 21st, 2009Being pregnant can and should be one of the most exciting and fulfilling times of a woman’s life, but unfortunately it can also be one of the most stressful times too. The woman needs to have ripened and released a healthy egg from one of her ovaries. This travels down one of her two fallopian tubes, stroked along its length by the tiny, finger-like cilia fronds which line the tubes.
Sperm then swim past the cervix, through the womb and up into the fallopian tubes to meet the descending egg. Eggs can live about 24 hours and sperm may live for two to three days, so they need to find each other within this fairly brief period. Several sperm may reach the egg at about the same time, but one needs to be able to break through the egg’s protective shell and get inside.
Once this has happened, the nucleus of the sperm fuses with that of the egg and the egg’s wall becomes impenetrable to other sperm. The egg spends the next two or three days passing down the remainder of the fallopian tube, then reaches the womb cavity, where it floats free for two or three days. Conception has now taken place.
Inside the fertilized egg, the combined ball of egg and sperm nuclei have been dividing, first in two, then four, eight, sixteen and so on, to develop into a cluster of cells called an embryo. when a sperm cell fuses with an egg cell, the result is a ball of their nuclei. Sperm and egg each donate 23 chromosomes, making a set of 23 pairs in all. These form the genetic blueprint for your future baby, and cover everything from hair and eye color to blood group. However, it is the father who determines a baby’s gender. Women’s cells have two X chromosomes, so egg cells always contribute an X chromosome; whereas sperm cells may contain either one X or one Y. When a Y chromosome combines with an X, it results in a male baby. If an X-carrying sperm fertilizes the egg, the baby will be a girl.
The embryo embeds itself in the blond-rich lining of the womb. You are now technically pregnant. However, it is believed that as many as 40 per cent of pregnancies are lost at this stage because the embryo does not implant itself properly.
The womb lining is kept in place (rather than being shed in a normal monthly period) by extra progesterone produced by your ovaries. It is the major upsurge in the amount of this hormone in the body that makes many pregnant women feel nauseous in the first few weeks of pregnancy.
This entire process, made to look so easy by couples who conceive quickly, or accidentally, is very finely balanced throughout. It is thought that perhaps as many as 20 per cent of embryos which do implant are lost in what seems to be a late period.
