A high-risk pregnancy is such a pregnancy in which the risk of illness or death of the mother or the newborn baby before or after birth is higher than usual.
To identify high-risk pregnancy, the doctor examines a pregnant woman in order to determine whether she has the disease or symptoms that increase the likelihood of disease or the death of her or the foetus during pregnancy (risk factors). Identification of high-risk pregnancy is only necessary to ensure that women who need intensive medical care have received it on time and in full.
A woman with a high-risk pregnancy can be sent to the department of antenatal (perinatal) monitoring (the term “perinatal” is used to refer to the events that occur before, during or after delivery). These offices are usually related to midwifery services and neonatal intensive care unit, which ensures the highest level of care for pregnant women and infants. Doctors often refer women to the center of perinatal surveillance before birth, as early medical supervision substantially reduces the likelihood of disease or the death of the child. Women are also sent to this center during childbirth if there are unexpected complications. As a rule, the most common reason for the referral – a high probability of premature birth (before 37 weeks). Treatment in the center of perinatal surveillance reduces the likelihood of premature birth.
Risk factors before pregnancy
Before a woman becomes pregnant, she may already have some diseases and disorders that increase the risk during pregnancy. In addition, a woman who had complications in previous pregnancies has the increased chance of developing the same complications in subsequent pregnancies.
Most common Risk factors
The woman’s age affects the risk of pregnancy. The girls aged 15 and younger are more likely to develop preeclampsia ( a condition during pregnancy when the blood pressure rises, there is protein in the urine, and there is an accumulation of fluid in the tissues) and eclampsia (seizures resulting from pre-eclampsia). They are also more likely to give a birth of an underweight or a premature child. Women aged 35 years and older have the high risk of the high blood pressure, diabetes, the presence of fibroids (benign growths) in the uterus and development of the disease during childbirth. The risk of birth of a baby with a chromosomal abnormality such as Down syndrome significantly increases after 35 years. If an old pregnant woman is concerned about the possibility of occurrence of anomalies in the foetus she can conduct a study of chorionic villi, or amniocentesis to determine the composition of foetal chromosomes.
If a woman has had three consecutive miscarriages (spontaneous abortion) in the first three months of previous pregnancies, the next miscarriage she may have with the probability of 35%. Spontaneous abortion is also more likely in women who have previously given stillbirth between the 4th and 8th months of pregnancy or had a premature birth in previous pregnancies. Before trying a new conception, a woman who had a miscarriage is recommended to be screened to detect possible chromosomal or hormonal diseases, structural defects of the uterus or cervix, connective tissue diseases, such as systemic lupus erythematosus, or the immune response to the foetus. If the cause of spontaneous abortion is revealed, the risk can be eliminated.
Stillbirth or neonatal death may be due to chromosomal abnormalities, as well as the presence of diabetes mellitus, chronic kidney disease or blood vessels, high blood pressure or connective tissue disorders such as systemic lupus erythematosus.
If a woman has had a baby weighing at birth more than 4.2 kg (9.3 lbs), she may have diabetes. The probability of spontaneous abortion or the death of the woman or baby is increased if the woman is suffering from diabetes during pregnancy.
If a woman has had a baby with hemolytic disease, so the next newborn is likely to have the likelihood of the same disease. Furthermore, the severity of the disease in the previous child determines its severity in the future. The disease develops when a pregnant woman having a Rh-negative blood, has the foetus which blood is Rh-positive (i.e. there is an incompatibility of the Rh factors). The mother produces antibodies against the foetal blood (there is a sensitization to the Rh factor); these antibodies destroy foetal red blood cells. In such cases, the blood is tested in both parents. If the father has two genes of Rh-positive blood, all his children will have Rh-positive blood. If he has only Rh positive gene, the probability of Rhesus positive blood of the child is about 50%.
Diseases of the pregnant woman
Some diseases of the pregnant woman can be dangerous for both her and the foetus. The most important of them: chronic high blood pressure, kidney disease, diabetes, severe heart disease, sickle cell anemia, thyroid disease, systemic lupus erythematosus, disorders of blood coagulation.
Risk factors during pregnancy
Even healthy pregnant women can be exposed to adverse factors that increase the likelihood of violations of the foetus or her own health. For example, she may come in contact with such teratogenic factors (influences that cause birth defects), as radiation, some chemicals, drugs and infections, a disease or a complication associated with pregnancy.
Effect of drugs and infections
Substances that can cause congenital malformations of the foetus during pregnancy include alcohol, phenytoin, drugs that counteract the effect of folic acid (lithium drugs, streptomycin, tetracycline, thalidomide). Infections that can cause birth defects include herpes simplex, viral hepatitis, influenza, Paraty (mumps), rubella, chicken pox, syphilis, listeriosis, toxoplasmosis, a disease caused by the Coxsackie virus and cytomegalovirus.
Although smoking is harmful to both the mother and the fetus but only about 20% of women smokers quit smoking during pregnancy. The most frequent consequence of smoking to the fetus during pregnancy is the low weight of such child: the more a woman smokes during pregnancy the less the weight of the child. This effect can be seen more among older women who are more likely to have a child with lower weight and height.
Congenital malformations of the heart, brain and face are more common in infants born to pregnant smokers than non-smokers. Maternal smoking may increase the risk of the syndrome of sudden infant death.
Drinking alcohol during pregnancy
Drinking alcohol during pregnancy is the leading cause of birth defects.
Foetal alcohol syndrome includes growth retardation before or after birth, facial defects, a small amount of the head (microcephaly), probably due to insufficient development of the brain and impairs mental development. Mental retardation is a result of the foetal alcohol syndrome more often than the impact of any other known causes. Moreover, alcohol can cause other complications: from abortion to severe behavioral disorders in the newborn or the developing child, such as anti-social behavior and an inability to concentrate.
Drug abuse is noticed in the increasing number of pregnant women. In order to examine the urine of a woman on heroin, morphine, amphetamines, barbiturates, codeine, cocaine, marijuana, methadone and phenothiazines, an inexpensive laboratory test called chromatography can be used. Injecting drug addicts, that is, drug addicts using syringes for drug use, have the higher risk of ill anemia, a blood infection (bacteremia) and heart valves (endocarditis), skin abscess, hepatitis, phlebitis, pneumonia, tetanus and sexually transmitted diseases (in including AIDS).
Complications of pregnancy
The most common causes of bleeding in the last 3 months of pregnancy is a pathological placenta previa, premature detachment of the placenta, vaginal or cervical disease, such as the infectious lesion. All women with the advent of this period, the risk of miscarriage bleeding, severe bleeding or death during childbirth is increased. Ultrasonography (ultrasound) examination of cervical smear can help to determine the cause of bleeding.
Conditions associated with the amniotic fluid
The excess of amniotic fluid (polyhydramnios) in the membranes surrounding the fetus stretches the uterus and puts pressure on the diaphragm of women. Sometimes this complication leads to respiratory failure in women and premature birth.
Preterm birth is more likely to be if there are some defects in the uterus or the structure of the cervix of the pregnant woman, bleeding, mental or physical stress or multiple pregnancies, or if she has come through the surgery on the uterus.
Having multiple fetuses in the uterus also increases the likelihood of congenital malformations in the fetus and complications in childbirth.
During pregnancy, which lasts more than 42 weeks, foetal death is 3 times more likely to happen than in normal pregnancy. To monitor the status of the foetus, electronic monitoring of cardiac activity and ultrasonography need to be used.