A high-risk pregnancy is one in which
- based on the medical history of the expectant mother (so-called anamnestic risks) or
- due to an examination finding during the current pregnancy(pregnancy-related risks)
certain situations that increase the risk of complications compared to a "normal pregnancy". The feared complications can affect the pregnancy itself or the birth.
Pregnancies that are classified as high-risk pregnancies therefore require more intensive care. The expectant mother then benefits from closer and more intensive medical care and monitoring during the pregnancy and birth.
A high-risk pregnancy does not mean that there is an acute danger to the mother and/or child. Around 75 percent of pregnancies are high-risk pregnancies as defined by the Joint Federal Committee (GBA). They are recorded in the maternity record.
However, only 40 to 50 percent of pregnancies are classified as high-risk pregnancies. At the same time, around 97 percent of children are born healthy.
In certain situations, high-risk pregnancies can be accompanied by a high-risk birth. This applies, for example, to the following findings:
- Premature birth,
- Placenta praevia (risk of bleeding or premature placental abruption),
- Any discrepancies between the size or position of the baby and the birth canal.
The aim of medical prenatal care is to enable doctors to identify high-risk pregnancies and high-risk births as early as possible.
The first step is a consultation, the so-called anamnesis. The doctor asks about
- past and current illnesses and complaints,
- pregnancies and births as well as
- medications taken.
This is followed by various examinations. Based on his findings, the doctor can assess whether there may be an increased health risk during the pregnancy or birth. The doctor will provide a risk assessment. This allows the therapeutic and, in particular, preventive measures for individual prenatal care to be planned.
In Germany, the maternity guidelines of the Joint Federal Committee exist for this purpose. These regulate the medical care of patients with statutory health insurance during pregnancy and after delivery. These include, in particular, the scope and timing
- the preventive services,
- diagnostic services and
- therapeutic services.
These guidelines also specify the criteria for classifying a pregnancy as a high-risk pregnancy.
Classification as a high-risk pregnancy is based on the medical history and an examination © Blue Planet Studio | AdobeStock
The assessment of any anamnestic risks includes factors such as
- Age,
- current and past illnesses,
- surgical interventions performed and
- complications or certain circumstances during previous pregnancies and births.
are taken into account.
Chronic illnesses
Diseases that can mean an increased risk for mother and/or child include, for example
In most cases, a chronic illness is not an obstacle to pregnancy today. In the past, women with diabetes, epilepsy or multiple sclerosis were advised to avoid pregnancy. Today, these illnesses are no longer a reason to avoid pregnancy.
Nevertheless, health risks for mother and child must be known in order to ensure optimal care during pregnancy. A safe pregnancy is then ensured by
- Adapted medication intake,
- additional preventive appointments or
- additional examination methods.
Age of the mother
Pregnant women who
- have their first child when they are over 35 or under 18, or
- who are over 40 and become pregnant again,
are classified as high-risk pregnancies.
A woman's fertility drops noticeably from the age of 30. At the same time, the probability of a chromosomal abnormality in the child increases significantly from the age of 35. However, most fetuses with chromosomal abnormalities are so severe that they die in the womb. For example, only about every second child with trisomy 21 (Down's syndrome) is viable.
The probability of a child with Down's syndrome being born alive is therefore
- at 25 years of age 1:1300 (0.08%),
- 1:365 (0.27%) at the age of 35 and
- 1:30 (3.3%) at the age of 45.
Older pregnant women also have a higher risk of pregnancy-related illnesses in the mother. These include gestational diabetes or high blood pressure, for example.
Age of the father
The age of the father plays
- in the development of certain diseases in the child, as well as
- for some pregnancy risks
a role. According to a study by the University of Zurich, for example, very young fathers appear to contribute to an increased risk of Down's syndrome.
According to a study by the Danish University of Aarhus, the risk of premature birth is significantly increased in fathers over 50 years of age.
Obstetric and gynecological risk factors
Generally speaking, women with more than four children have an increased risk of pregnancy. They have an increased risk of genetic defects and placental insufficiency. Placental insufficiency means that the unborn child cannot be supplied with sufficient oxygen and nutrients.
This results in an increased risk of complications during birth due to possible birth mechanics risks as a result of overstressing the maternal organism.
If complications have already occurred in previous pregnancies, the current pregnancy is also considered a high-risk pregnancy.
This applies to the following circumstances in particular:
- Multiple miscarriages or premature births
- Stillborn or severely impaired children beforehand
- Delivery of children weighing over 4000 grams (so-called macrosomia) or underdevelopment (so-called hypotrophy or growth retardation) beforehand
- Multiple pregnancies or births beforehand
- Complications in the context of previous deliveries:
- atypical placental localization(placenta praevia),
- premature placental abruption(abruptio placentae),
- Postpartum hemorrhage (postpartum hemorrhage),
- coagulation disorders,
- cramps or
- vascular occlusion caused by a blood clot (thromboembolism).
Gynecological risk factors include
- the performance of infertility treatment,
- surgical interventions on the uterus, including
- Caesarean section,
- removal of a myoma or benign tumor of the uterine musculature or due to a malformation of the uterus.
Certain health problems may only develop or become apparent during pregnancy. As soon as the risk has been determined by an examination, the pregnancy is then considered a high-risk pregnancy.
Hypertensive pregnancy diseases
Pregnancy hypertension is decisively responsible for
- Diseases and complications as well as
- mortality of mother and child
during pregnancy. Pregnant women with high blood pressure are therefore considered high-risk pregnancies. Hypertensive pregnancy diseases include, among others
- Gestational hypertension: raised blood pressure in the mother after the 20th week of pregnancy,
- Pre-eclampsia: increased blood pressure and additional protein in the urine,
- Eclampsia: seizures occurring as part of pre-eclampsia,
- HELLP syndrome: dissolution of red blood cells, increased liver enzymes, reduced platelet count.
Blood group incompatibility
In some pregnancies, mother and child have different blood groups and rhesus factors. The mother can then develop antibodies against the red blood cells, usually shortly before birth.
During another pregnancy, these lead to a reaction of the mother's immune system to the baby, which can be damaged as a result.
Gynecological factors
The following situations are also assumed to increase the risk of the pregnancy progressing:
- Multiple pregnancies and abnormal position of the baby in the uterus, e.g. transverse position,
- Bleeding from the uterus (uterine bleeding),
- imminent premature birth due to premature labor or cervical insufficiency, and
- Exceeding or unclear due date.
Other risk factors
- Anemia: anemia, reduced haemoglobin value (Hb value),
- Gestational diabetes (gestational diabetes).
Due to the increased risk for the expectant mother and the unborn child, high-risk pregnancies require more intensive preventive care. For this reason, closer meshed examinations are carried out in the case of a high-risk pregnancy:
- up to the 32nd week of pregnancy more frequently than at four-week intervals and
- in the last 8 weeks of pregnancy more frequently than every two weeks.
In particularly critical cases, the pregnant woman may also be referred for inpatient monitoring in the last few weeks. This often takes place in an appropriate hospital with perinatal care. Such hospitals specialize in the health care of pregnant women and fetuses shortly before and after birth.
The expectant mother decides which examinations or measures she ultimately has carried out. This is why a trusting relationship with the doctor is particularly important during pregnancy.
In the case of high-risk pregnancies, additional examinations may be necessary depending on the findings and medical history. These include the following examinations.
Standard sonography
A standard ultrasound scan is recommended in the following situations:
- In the case of repeated uterine bleeding,
- in the case of a disturbed early pregnancy,
- in early pregnancy with an intrauterine device (IUD) in place,
- if the uterus is enlarged due to multiple myomas(uterus myomatosus) and cysts or solid tumors of the fallopian tubes or ovaries(adnexal tumor),
- for cervical measurement in cases of suspected cervical weakness,
- in the event of premature rupture of the membranes and/or contractions,
- to monitor the progress of an existing fetal anomaly or disease,
- for suspected premature placental abruption and
- to check if the course of labor is disturbed.
Extended ultrasound examination
With the help of a high-resolution ultrasound device, the organs can be examined even more closely. This examination is therefore called fine diagnostic sonography. It can be used in the following situations:
- To check fetal growth in the event of suspected developmental disorders in the child,
- to monitor a multiple pregnancy,
- to check the position of the placenta if placenta praevia is detected (position of the placenta in front of the inner cervix),
- to check first-time bleeding within the uterus and
- for suspected positional anomalies from the 36th week of pregnancy.
Doppler sonography
An examination of the blood vessels and blood flow using a special ultrasound device is carried out in the following situations, for example:
- If fetal growth disorders, diseases or malformations are suspected,
- in the case of hypertensive pregnancy disorders,
- to check the condition after fetal death or after pre-eclampsia/eclampsia,
- for abnormalities in the fetal heart rate,
- in the case of different growth in multiple births,
- suspected heart defects/heart disease.
Cardiotocographic examinations (heart sound contractions recorder)
Cardiotocography (CTG) is the simultaneous recording of the baby's heartbeat and contractions. It is used for the early detection of fetal problems.
According to maternity guidelines, a CTG should
- before the 28th week of pregnancy if premature contractions are suspected and if contractions have been inhibited by medication or
- from the 28th week of pregnancy if changes in heart rate are detected.
should be carried out.
Further examinations
As part of an amniocentesis(amniotic fluid test), amniotic fluid is taken via a cannula. The doctor pushes it through the skin into the amniotic sac.
The amniotic fluid is then analyzed for
- some chromosomal abnormalities,
- hereditary diseases and some other conditions,
- infections,
- blood group incompatibility and
- lung maturity in case of impending premature birth
are examined. Ideally, amniocentesis should be performed between the 14th and 19th week of pregnancy.
In contrast, a chorionic villus sampling(placenta puncture) is possible as early as the 10th to 12th week of pregnancy. Chorionic villus sampling also involves inserting a cannula through the abdominal wall. However, the doctor does not puncture the amniotic sac. He merely takes a tissue sample from the chorionic villi.
This examination method can also be used to clarify chromosomal abnormalities and some hereditary diseases.
