SPECIAL PROBLEMS IN PREGNANCY
Although in most women pregnancy follows a normal healthy course, some women develop severe problems. Problems of pregnancy include the following.
Anywhere from 10 to 40 percent of human pregnancies end in miscarriage, or spontaneous abortion. Often, increased vaginal bleeding and cramping occurs around the time of a normal menstrual period and may go unnoticed by the woman. Genetic analysis of this material suggests that at least 50 percent of these spontaneous miscarriages result from major chromosomal abnormalities.
A pregnancy that occurs at a site other than inside the uterus, such as in the Fallopian tube, on the ovary, or at sites outside the abdomen, are termed ectopic. Such pregnancies are generally not viable and can be life-threatening to the mother.
A variety of infectious diseases, especially German measles (rubella), toxoplasmosis, and chicken pox, can lead to abnormalities of fetal growth and development. Some sexually transmitted diseases can be transmitted to the fetus, particularly gonorrhea, syphilis, and AIDS. Routine tests are conducted before and during pregnancy to test for these infections and, if possible, treat them before harm is done to the fetus.
The Rh factor is a specific antigen located on red blood cells. If a mother has Rh negative blood and carries an Rh positive child, there is a possibility that the Rh positive blood cells of the child will cross the placental barrier, triggering antibody production to the Rh factor in the mother. These maternal antibodies may attack the blood of a subsequent Rh positive fetus, causing a severe and often fatal type of anemia. Doctors are now able to prevent Rh disease with a vaccine. Once common, the disease is now rare, and its eradication is one of the major triumphs of modern obstetrics.
Diabetes is a common complication of pregnancy. High blood sugar in the mother can lead to very large babies. Diabetes that develops during pregnancy is called gestational diabetes. It can be managed with diet alone, or in combination with insulin. Women previously diagnosed with diabetes develop an increase in their insulin requirements when pregnant, which often makes the disease difficult to control. In cases where diabetes is advanced, kidney and placental impairment may occur, which also may lead to fetal growth problems.
Women with chronic hypertension, or high blood pressure, have an increase in certain complications, particularly kidney disease. In addition there are certain hypertension diseases that can develop during pregnancy. The causes of these diseases are poorly understood, and as a result they are given many names, including pregnancy-induced hypertension, toxemia, preeclampsia, or EPH gestosis. These diseases are characterized by protein in the urine and swelling, or edema, that can lead to seizures, liver damage, kidney damage, bleeding abnormalities, and poor fetal growth and outcome.
Eclampsia, the occurrence of seizures, is considered the most severe manifestation of this process.
Anemia, or a low blood-cell count, is common during pregnancy. Women often have a chronic iron-deficiency anemia before pregnancy because of monthly blood loss from menstruation. During pregnancy this is compounded by the increased nutritional requirements to support the fetus. In addition to iron-deficiency anemia, there are also other deficiency states that commonly cause anemia, such as folate deficiency. In developing countries, anemia owing to malaria is a major cause of illness.
Pregnancy over Age 35
It is becoming an increasingly common event for women over age 35 to become pregnant. Generally, these women do well if they were in good health prior to the pregnancy. Certain conditions are more common in older pregnant women, however, such as hypertension and gestational diabetes. In addition, for each yearover the age of 35, there is an increased risk of giving birth to a child with chromosomal anomalies, such as Down syndrome. This risk increases to 1 out of every 38 births by the age of 44. A variety of prenatal tests to diagnose chromosomal disorders is available for older pregnant women.
It is ideal for the growing fetus if the mother gains at least 11.3-13.6 kg (25-30 lb) during her pregnancy. Low prepregnancy weight or low weight gain, particularly if food is low in protein, vitamins and minerals, can impair fetal growth at the time when brain cells are rapidly developing.
Smoking, Alcohol, Drugs
Smoking during pregnancy affects fetal growth and development because of increased carbon monoxide and decreased oxygen in the blood. Heavy drinking of alcohol impairs the mother's nutrition and can cause damage to her liver. In addition, the fetus can develop fetal alcohol syndrome, a cluster of mental and physical birth defects.
The use of such drugs as marijuana, amphetamines, cocaine, and heroin all adversely affect the fetus. Babies are smaller, sicker, and more likely to be stillborn. In addition, babies born to women who used drugs during pregnancy may be addicted to the drug at birth. Cocaine is a particularly dangerous drug during pregnancy because it constricts the blood flow to the developing fetus.