From Fertilization to the Birth of the Baby

In the last three or four months of pregnancy, as the foetus increases in size, things get a bot crowded inside the abdomen of the mother. Of course, the uterus is entirely separate from the stomach (in spite of what little children are sometimes told about the baby growing in its mother's tummy), but as the uterus expands, the bladder and stomach and all the other organs are pressed upon.

That explains why an expectant mother needs to urinate more often than usuas and eats smaller, more frequent meals. It seems a miracle that the remarkable plan of growth for the body was already contained in the DNA of the original fertilized cell. There was a set pettern that could not be changed.

Not only was it determined in advance that what would be born was a human being, and not a mouse or cow or elephant, but also determined were all of the thousands of inherited traits that make a person truly the product of his parents and ancestors.

You may wonder what the effect on the foetus is if the pregnant woman smokes, drinks alcohol, or takes drugs. Studies of these effects are not complete, but it is known that mothers who smoke tend to have smaller babies (this is not to say less healthy ones) than those who do not. Also, when the mother smokes, the heartbeat of the foetus speeds up somewhat.

When the mother drinks alcohol, the baby's movements inside the uterus are slowed down while the alcohol is in the mother's bloodstream, but this does not harm the baby as far as we know. Marijuana also has a temporary effect on the baby but not a harmful one. However, the drug heroin can be very injurious to the baby.

 

As the mother becomes addicted to heroin, the baby also becomes addicted, and after it is born it goes through painful and serious withdrawal symptoms, just as an adult does when taken off the drug. One birth is every ninety or so produces twins, (One in about every eight thousand produces triplets) Twins are formed in two ways. One is that each of the mother's two ovaries releases two eggs.

Thus, each fallopian tube contains an egg, or one tube contains two eggs, and, when the sperm cells enter the tubes, both eggs are fertilized. Each egg becomes seperately implanted in the uterus, and each embryo has its own placenta. Twins who start this way are really ordinary brothers or sisters whose original egg cells just happened to be fertilized at the same time and who were therefore born at the same time.

They may be of the same or opposite sex, and they do not look any more alike than brothers and sisters born at different times. They are called fraternal twins. The other way twins can occur is for the original fertilized cell, after implanting itself, to divide once into two separate parts and for each embryo then to develop independently.

These single-egg twins are always of teh same sex since they were started by the same sperm cell, and ususlly they look so much alike that they are hard to tell apart. They are called identical twins. Much rarer are triplets, quadruplets, and quintuplets, who are usually the products of two or more eggs. Triplets most commonly result from two eggs, one of which divides to produce a pair of identical twins, while the other egg produces a single infant. The famous Dionne quintuplets were thought to be the products of one egg dividing into five parts, all with the same placenta. The Diligenti quintuplets from Argentina appear to have come from only three eggs.