Factors affecting pre-natal development a. Maternal Health Since the placenta cannot filter out extremely small disease carriers, such as viruses, children can be born with malaria, measles, chicken pox, mumps, syphilis, or other venereal diseases that have been transmitted from the mother. Rubella is the most widespread of the viruses that have a teratogenic effect. If a pregnant woman contracts rubella in the first three months of pregnancy, she is likely to give birth to a child with a congenital abnormality such as heart disease, cataracts, deafness, or mental retardation.
Interestingly, there is not a direct relationship between the severity of the disease in the mother and its effect on the fetus. For example, women who have had mild attacks of rubella have given birth to babies with severe abnormalities. Although rubella might be the most widespread disease, acquired immunodeficiency syndrome (AIDS) is by far the most frightening and the one that has received the most publicity. The vast majority of children with AIDS contracted the disease sometime between early pregnancy. The disease is usually transmitted from the mother through the uterus during pregnancy or is acquired by the off-spring at birth.
Toxemia is a frightening condition that is potentially fatal for the mother and the fetus. It is characterized by high blood pressure, swelling, and weight gain due to a build-up of fluid in the body tissues, and the presence of protein in the mother’s urine. In severe cases the woman may go into convulsions or coma, placing a tremendous strain on her, which is carried over to the fetus. Women with toxemia frequently give birth to premature babies or to babies smaller than average for their gestational age. Like many other types of blood-pressure disorders, however, toxemia can be treated through medication and diet.
Anoxia is a condition in which the brain of the baby does not receive enough oxygen to allow it to develop properly. Anoxia can cause certain forms of epilepsy, mental deficiency, cerebral palsy, and behavior disorders. If the amount of brain damage is not too severe, however, it may be possible to compensate for the disorder to some extent. Epilepsy can often be controlled with drugs, for instance, and many children with cerebral palsy can learn to control their affected muscles. b. Maternal Nutrition Just as other aspects of physical health are important, so is the mother’s diet.
While physicians and researchers have long realized that pregnancy puts additional demands on the mother’s body, they used to assume that the fetus’ nutritional needs would be met first, even at the mother’s expense. The current opinion, however, is that the prenatal development of the fetus and its growth and development after birth are directly related to maternal diet. Women who follow nutritionally sound diets during pregnancy give birth to babies of normal or above-normal size. Their babies are less likely to contract bronchitis, pneumonia, or colds during early infancy and have better developed teeth and bones.
The mothers have fewer complications during pregnancy and, on the average, spend less time in labor. The less time in labor, the easier the birth and the less stress the mother and child experience. But if the mother’s diet is low in certain vitamins and minerals when she is pregnant, the child may suffer from specific weaknesses. Insufficient iron may lead to anemia in the infant, and a low intake of calcium may cause poor bone formation. If there is an insufficient amount of protein in the mother’s diet, the baby may be smaller than average and may suffer from mental retardation, with almost 20 percent fewer brain cells. . Drugs Chemicals (over-the-counter and prescribed pharmaceuticals as well as illegal substances) can cause a wide range of congenital abnormalities that account for about 10 percent of birth defects. The severity of the abnormality depends on the amount of the chemical the mother is exposed to, the developmental stage of the fetus, and the period of time over which the mother’s exposure to the chemical takes place. In terms of narcotics, women who are addicted to heroin, morphine, or methadone give birth to addicted babies.
Soon after birth, the babies show symptoms of withdrawal, including tremors, convulsions, difficulty breathing, and intestinal disturbances. d. Tobacco Maternal smoking increases the risk of spontaneous abortions, bleeding during pregnancy, premature rupture of the amniotic sac, and fetal deaths and deaths of newborns. Women who smoke during pregnancy give birth to babies who are about one-half pound (225 grams) lighter (on the average) and smaller in all dimensions (for example, length and head circumference) than babies of non-smokers, are born prematurely, and have other health problems. . Alcohol The effects of alcohol are almost undisputed. Fetal alcohol syndrome (FAS), identified in 1973, is perhaps one of the best known and best documented outcomes of drinking, affecting approximately one out of every 750 births. And it is not just the heavy drinker who may place her fetus in danger. It has been found that women having one or more drinks daily were three times more likely to miscarry than women who had less than one drink daily. Alcohol can weaken the male germ cell. f.
Emotional State of Mother Studies have indicated that pregnant mothers who are experiencing high levels of stress or depression during pregnancy tend to transfer distress signals to their baby. This can in turn produces raised levels of those hormones which speed up delivery. g. Maternal Age Teenage mothers and those over thirty-five years of age have a higher risk of miscarriage, premature birth, and some birth defects than mothers in the prime childbearing years. Some of the reasons are fairly obvious.
Very young mothers have not yet completed their own development, and the reproductive system may not be quite ready to function smoothly or effectively. In older women the reproductive system may be past its most efficient functioning. In both cases, pregnancy puts an extra strain on a body that is not fully able to bear it. Furthermore, there is some reason to think that a woman’s ova may deteriorate with age, leading to a greater risk of birth defects. Women have all their ova in partly developed form when they are born.
So a woman, who becomes pregnant at age thirty-seven, for example, is “using” an ovum that has been more or less exposed to thirty-seven years’ worth of harmful chemicals, radiation, virus infections, and whatever else has happened to her body. This may explain why, for instance, Down syndrome is most common in children born to mothers over forty years of age. It is quite possible that men’s sperm may also be susceptible to chemicals and radiation effects over time. Furthermore, there may be genetic disorders that cause changes in sperm structure.