MEDICAL CARE: INTERNAL CHANGES DURING PREGNANCY. LIFE-SUPPORT SYSTEM

Due to hormonal changes, most women have their sexual desires markedly augmented so that the zenith coincides with the moment of ovulation or soon after. So it is not all apparent chance and luck. It is really by very cleverly devised means that it occurs so frequently this way.

As soon as conception occurs, and the chromosomal count is reconstituted back to forty-six (including the XX or XY ones giving the individual his sex characteristic), the cell commences to divide and divide again. All this time it is gradually propelled down the length of the Fallopian tube by gentle muscular movement aided by pulsations from the "cilia," little hair like projections that protrude from the cells lining the tube. These set up sweeping waves that help carry the egg towards the cavity of the womb.

By the time the egg has reached the womb, the lining is quite ready to accept it. Very quickly the egg becomes embedded in the endometrial layers, usually at the upper part of the womb, either toward the front or back. Very occasionally it becomes embedded low down near the uterine outlet. But this can lead to problems at a later stage, and more has been told of this in relation to a condition called placenta praevia, in another chapter.

By now the egg has become a solid mass of cells called a morula. Under the influence of hormones from the corpus luteum of the ovary, small projections called villi grow from the outer surface of the egg. These help it become embedded even more intimately. Very rapidly, in fact, in a matter of days—the junction between the uterine wall and the egg develops into a powerful organ which is to become the placenta, and finally the ' 'after-birth'' at the time of baby's birth.

 

Life-support System

This is the organ through which the developing baby will come into very close contact with the mother's blood supply. In fact, this becomes its supply channel, for food, oxygen, vitamins and all other nutritional supplies. It also becomes the developing infant's method of disposing of its own waste products.

At no time does the mother's blood actually come into contact with that of the baby. The two are completely separate, but they are separated only by a very fine barrier. Through this barrier diffuse both ways, foods and waste products. It is an amazing exchange system, but a very workable and practical one.

The fertilized egg quickly develops. The placenta forms and the rest of the womb fills with fluid called liquor amnii, or amniotic fluid. The baby is known as an embryo in the early stages, and as it further develops it is called a foetus (which is sometimes also spelled fetus).

Besides being the exchange site for food and oxygen, the placenta is also a powerful factory. It produces chemicals called hormones which are vital to the safe development of the baby. An important one is called "H.C.G.," short for human chorionic gonadotrophin. After a few weeks this production becomes high, so much so that excessive amounts circulate in the blood and are excreted by the mother in her urine.

This forms the basis of the pregnancy tests which are often used to prove or disprove the presence of pregnancy in a woman who is unsure. Using a special technique called radio immunoassay, or a simpler "immunological test" on the urine, the hormone's presence can quickly be determined. It means the doctor is taking advantage of a naturally occurring situation when he has this test carried out.

 

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GENERAL HEALTH