Pregnancy High Risk

Pregnancy at high risk is a pregnancy in which an increase in risk factors complicating the course of pregnancy or increasing mortality before or after delivery is possible for the mother, fetus or newborn.

In the United States, the maternal mortality rate is 6 per 100,000 births; mortality is 3-4 times higher in color women. The main causes of death are bleeding, arterial hypertension associated with pregnancy, pulmonary embolism and infection. The level of perinatal mortality in offspring is 11.5 per 1,000 births: 6.7 per 1,000 for the fetus and 4.8 per 1,000 for the newborn (<28 days). The most frequent causes of death are congenital malformations and premature births.

The study of risk factors is the usual stage of prenatal diagnosis. Risk factors are evaluated throughout the entire pregnancy or soon after delivery and at any time with a change in risk factors. The risk factors are systematized; each factor increases the risk as a whole. Pregnant women at high risk require careful monitoring and referral to a specialist doctor in the perinatal center. Referral to a specialist doctor before delivery results in a reduction in complications and mortality in newborns.

The main indications for referral to a specialist doctor before delivery are the threat of premature birth (often due to premature rupture of membranes), hypertension associated with pregnancy, and bleeding.

[1], [2], [3], [4], [5], [6], [7]

Risk factors for high-risk pregnancy

Risk factors include maternal health disorders, physical and social characteristics, age, complications of previous pregnancies (eg, spontaneous abortions), complications of ongoing pregnancy, childbirth and delivery.

Arterial hypertension. Pregnant women suffer from chronic arterial hypertension (HAG) if they had hypertension before pregnancy or developed before the 20th week of pregnancy. CAG should be differentiated from hypertension caused by pregnancy that occurred after the 20th week of gestation. Arterial hypertension is defined as a systolic hypertension with a blood pressure of more than 140 mm Hg. And diastolic blood pressure more than 90 mm Hg. More than 24 hours. Arterial hypertension increases the risk of delaying intrauterine development of the fetus and reduces uteroplacental blood flow. CAG increases the risk of pre-eclampsia up to 50%. Poorly managed arterial hypertension increases the risk of placental abruption from 2 to 10%.

When planning pregnancy, women with hypertension should undergo counseling taking into account all the risk factors. In the presence of pregnancy in such women it is recommended to begin prenatal preparation as soon as possible. It is necessary to study the function of the kidneys (measurement of creatinine and urea in blood serum), ophthalmoscopic examination, as well as examination of the cardiovascular system (auscultation, ECG, echocardiography). In each trimester of pregnancy a protein is determined in the daily urine, determination of uric acid, serum creatinine and hematocrit. To control fetal growth, ultrasonography is used at 28 weeks and then every few weeks. The growth retardation in the fetus is diagnosed with the help of dopplerometry by a specialist in prenatal diagnosis (for management of arterial hypertension during pregnancy).

Assessment of risk factors for pregnancy

Category

Risk factors

Points 1

Previously existing

Cardiovascular and renal impairment	Moderate and severe preeclampsia	10
	Chronic arterial hypertension	10
	Moderate, severe renal impairment	10
	Severe heart failure (class II-IV, NYHA classification)
	Eclampsia in history	5
	Pielit in the anamnesis	5
	Moderate heart failure (class I, NYHA classification)
	Moderate preeclampsia	5
	Acute pyelonephritis	5
	Cystitis in the anamnesis	1
	Acute cystitis	1
	Preeclampsia in history	1
Metabolic disorders	Insulin-dependent diabetes	10
	Previous endocrine ablation	10
	Thyroid disorders	5
	Prediabetes (controlled by diet gestational diabetes)	5
	Family history of diabetes	1
Obstetrical anamnesis	Exchange fetal transfusion with Rh-incompatibility	10
	Stillbirth	10
	Mature pregnancy (more than 42 weeks)	10
	Premature neonate	10
	Newborn, small to the term of gestation	10
	Fetal abnormality	10
	Polyhydramnion	10
	Multiple pregnancy	10
	Stillborn	10
	Cesarean section	5
	Habitual abortion	5
	Newborn baby> 4.5 kg	5
	Parity of birth> 5	5
	Epileptic seizure or cerebral palsy	5
	Malformations of the fetus	1
Other violations	Pathological results of cervical cytology
	Sickle-cell disease	10
	Positive serological results for STIs	5
	Severe anemia (hemoglobin <9 g / dL)	5
	Tuberculosis in the anamnesis or injection site induction with the introduction of the purified protein derivative> 10 mm
	Pulmonary disorders	5
	Moderate anemia (hemoglobin 9.0-10.9 g / dl)	1
Anatomical disorders	Malformations of the uterus	10
	Isthmicocervical insufficiency	10
	Narrow Pelvis	5
Maternal characteristics	Age 35 or <15 years	5
	Body weight <45.5 or> 91 kg	5
	Emotional problems	1

Prenatal factors

Teratogenic factors	Viral infections	5
	Severe influenza	5
	Excessive use of drugs	5
	Smoking 1 pack a day	1
	Moderate reception of alcohol	1
Complications of pregnancy	Only Rh-sensitization	5
	Vaginal discharge	5

During childbirth

Maternal factors	Moderate, severe preeclampsia	10
	Polyhydramnios (polyhydramnios) or oligohydramnion (malic acid)	10
	Amnionite	10
	Rupture of uterus	10
	Pregnancy period> 42 weeks	10
	Moderate preeclampsia	5
	Premature rupture of shells> 12 h	5
	Premature birth	5
	Primary weakness of labor	5
	Secondary weakness of labor	5
	Meperidine> 300 mg	5
	Magnesium sulphate> 25 g	5
	Childbirth> 20 h	5
	Second stage of labor> 2.5 h	5
	Clinically narrow pelvis	5
	Medical induction of childbirth	5
	Rapid birth (<3 h)	5
	Primary cesarean section	5
	Repeated cesarean section	5
	Elective induction of labor	1
	Prolonged latent phase	1
	Thetanus of the uterus	1
	Oxytocin overdose	1
Placental factors	Central placenta previa	10
	Placental abruption	10
	Regional placenta previa	1
Factors from the side of the fetus	Pathological presentation (pelvic, frontal, facial) or transverse position
	Multiple pregnancy	10
	Bradycardia in fetus> 30 min	10
	Birth in the pelvic presentation, extraction of the fetus behind the pelvic end
	Cord loss	10
	Fruit weight <2.5 kg	10
	Fetal acidosis <7.25 (step I)	10
	Fetal Tachycardia> 30 min	10
	Amniotic water, colored with meconium (dark)	10
	Amniotic water, colored with meconium (light)	5
	Operative delivery with forceps or vacuum extractor
	Births in the breech presentation, spontaneous or with the use of benefits
	General anesthesia	5
	Output obstetrical forceps	1
	Dystocia of the shoulders	1

¹ 10 or more points indicate a high risk.

NYHA - New York Heart Association; STIs are sexually transmitted infections.

Diabetes. Diabetes mellitus occurs in 3-5% of pregnancies, its effect on the course of pregnancy increases with the weight of patients. Pregnant women with previously existing insulin-dependent diabetes are at increased risk for pyelonephritis, ketoacidosis, hypertension associated with pregnancy, fetal death, malformations, macrosomia of the fetus (weight> 4.5 kg), and if there is vasculopathy, delayed fetal development. The need for insulin usually increases during pregnancy.

Women with gestational diabetes are at risk of hypertensive disorders and fetal macrosomia. A test for gestational diabetes is usually performed at the 24th-28th week of pregnancy or, in women with risk factors, during the 1st trimester of pregnancy. Risk factors include previous gestational diabetes, newborn macrosomnia in a previous pregnancy, family history of non-insulin-dependent diabetes, unexplained fetal loss and body mass index (BMI) of more than 30 kg / m ². A glucose tolerance test using 50 g of sugar is used. If the result is 140-200 mg / dL, glucose is determined after 2 hours; if the glucose level is more than 200 mg / dl or the results are pathological, then women are treated with diet and, if necessary, using insulin.

Quality control of blood glucose during pregnancy minimizes the risk of developing adverse outcomes associated with diabetes (treatment of diabetes during pregnancy).

Sexually Transmitted Infections. Intrauterine infection with syphilis can cause intrauterine fetal death, congenital malformations and disability. The risk of HIV transmission from mother to fetus in utero or perinatal is 30-50% within 6 months. Bacterial vaginosis, gonorrhea, urogenital chlamydia in pregnancy increase the risk of premature birth and premature rupture of the membranes. Conventional prenatal diagnosis includes screening tests to identify hidden forms of these diseases during the first prenatal visit.

The test for syphilis is repeated during pregnancy, if the risk of infection remains at the time of delivery. All pregnant women with these infections are treated with antimicrobials.

Treatment of bacterial vaginosis, gonorrhea and chlamydia can prevent premature rupture of the membranes in labor and reduce the risk of intrauterine infection of the fetus. Treatment of HIV infection with zidovudine or nevirapine reduces the risk of transmission by 2/3; the risk is significantly lower (<2%) when using a combination of two or three antiviral drugs.

These drugs are recommended for prescription, despite the potentially toxic effects on the fetus and the woman.

Pyelonephritis. Pyelonephritis increases the risk of premature rupture of membranes, premature birth and respiratory distress syndrome of the fetus. Pregnant women with pyelonephritis are hospitalized for diagnosis and treatment. First of all, a bacteriological study of urine with sowing on sensitivity to antibiotics is carried out.

Intravenous administration of antibiotics (for example, cephalosporins of the third generation in combination or without aminoglycosides), antipyretics and hydration correction medications is used. Pyelonephritis is the most common non-obstetric cause of hospitalization during pregnancy.

Assign specific antibiotics for oral administration, taking into account the pathogen within 24-48 hours after the cessation of fever, and also conduct a full course of antibiotic therapy for 7-10 days. Antibiotics for prophylactic purposes (for example, nitrofurantoin, trimethoprim-sulfamethoxazole) are prescribed during the rest of pregnancy with a periodic bacteriological study of urine.

Acute surgical diseases. Large surgical interventions, especially intra-abdominal, increase the risk of premature birth and intrauterine fetal death. During pregnancy, physiological changes occur that make it difficult to diagnose acute surgical diseases requiring urgent surgical intervention (for example, appendicitis, cholecystitis, intestinal obstruction), and thus worsen the results of treatment. After the operation, antibiotics and tocolytics are prescribed for 12-24 hours. If planned surgical treatment is needed during pregnancy, it is better to perform it in the 2nd trimester.

Pathology of the reproductive system. Malformations of the uterus and cervix (for example, the septum in the uterine cavity, bicornic uterus) lead to abnormalities in fetal development, pathological labor and increase the frequency of cesarean delivery. Fibroid tumors of the uterus can cause placenta pathology, may increase growth or degeneration of nodes during pregnancy; degeneration of the nodes leads to severe pain and the appearance of peritoneal symptoms. Isthmicocervical insufficiency often leads to premature birth. In women who had a myomectomy, during birth through the natural birth can occur spontaneous rupture of the uterus. Uterine flaws requiring surgical correction, which can not be performed during pregnancy, worsen the prognosis of pregnancy and childbirth.

Age of the mother. Adolescents, in whom pregnancy occurs in 13% of cases, prenatal preparation is neglected. As a result, the incidence of preeclampsia, premature birth and anemia is increasing, which often lead to a delay in intrauterine fetal development.

In women older than 35 years, the frequency of preeclampsia increases, especially against gestational diabetes, the incidence of anomalies in the contractile activity of the uterus during labor, abruption of the placenta, stillbirth and placenta prevalence increases. These women also have the most common disorders, such as chronic arterial hypertension, diabetes. It is necessary to carry out genetic testing, since the risk of chromosomal pathology in the fetus increases with increasing maternal age.

Mother's body weight. Pregnant women with a BMI of less than 19.8 (kg / m) before pregnancy are considered to be underweight women, which predisposes to the birth of a child with a low birth weight (<2.5 kg). Such women need to gain weight approximately 12.5-18 kg during pregnancy.

Pregnant women with a BMI greater than 29.0 (kg / m) before pregnancy are considered to be overweight patients, leading to hypertension, diabetes, miscarriage, fetal macrosomia, and an increased risk of caesarean section. Such women are recommended to limit weight gain to 7 kg during pregnancy.

The effect of teratogenic factors. Teratogenic factors (agents that lead to malformations of the fetus) are infections, drugs and physical agents. Developmental defects are most often formed between the 2 nd and 8 th weeks after conception (4-10 weeks after the last menses), when organs are laid. Other adverse factors are also possible. Pregnant women who have been exposed to teratogenic factors, as well as having increased risk factors, should be carefully examined by ultrasound to identify developmental anomalies.

To teratogenic infections include: simple herpes, viral hepatitis, rubella, chickenpox, syphilis, toxoplasmosis, cytomegalovirus and the Coxsackie virus. To teratogenic substances include alcohol, tobacco, some anticonvulsants, antibiotics and antihypertensive drugs.

Smoking is the most frequent addiction among pregnant women. The percentage of women who smoke moderately and significantly increases. Only 20% of smoking women stop smoking during pregnancy. Carbon monoxide and nicotine, found in cigarettes, lead to hypoxia and vasoconstriction, increasing the risk of spontaneous abortion (miscarriage or delivery within a period of less than 20 weeks), lead to a delay in intrauterine development of the fetus (weight at birth is on average 170 g less than Newborns whose mothers do not smoke), placental abruption, placenta previa, premature rupture of membranes, premature birth, chorioamnionitis and stillbirth. In newborns whose mothers smoke, anencephaly, congenital heart defects, maxillary cleft, physical and intellectual development lag, and behavioral disorders are more common. There is also a sudden death of an infant during sleep. Restriction or cessation of smoking reduces the risk of teratogenic effects.

Alcohol is the most common teratogenic factor. Taking alcohol during pregnancy increases the risk of spontaneous abortion. The risk depends on the amount of alcohol consumed, any amount is dangerous. Regular intake of alcohol reduces the mass of the child at birth by about 1 -1.3 kg. Even the intake of as much alcohol as 45 ml of alcohol per day (equivalent to about 3 servings) can cause fetal alcohol syndrome. This syndrome occurs in 2.2 per 1000 live births and includes a delay in intrauterine growth of the fetus, facial and cardiovascular defects, neurological dysfunction. Alcoholic fetal syndrome is the main cause of oligophrenia and can cause death of a newborn.

The use of cocaine also has an indirect risk (for example, a stroke in the mother or death during pregnancy). The use of cocaine can also lead to vasoconstriction and fetal hypoxia. Cocaine use increases the risk of spontaneous abortion, intrauterine growth retardation, placental abruption, premature birth, stillbirth and congenital malformations (eg CNS, urinary tract, skeletal malformations and isolated atresia).

Although the main metabolite of marijuana penetrates the placenta, nevertheless episodic use of marijuana does not increase the risk of congenital malformations, intrauterine growth retardation or postnatal neurological disorders.

Previous stillbirth. Causes of stillbirth (intrauterine fetal death at> 20 weeks) may be maternal, placental or embryonic factors. The presence in the anamnesis of data on stillbirth increases the risk of intrauterine fetal death in subsequent pregnancies. It is recommended to monitor the development of the fetus and evaluate its viability (apply non-stress tests and biophysical profile of the fetus). Treatment of abnormalities in the mother (eg, chronic hypertension, diabetes, infection) can reduce the risk of stillbirth in the current pregnancy.

Pre-premature delivery. Presence in the anamnesis of premature birth increases the risk of premature birth in subsequent pregnancies; if at previous premature birth the body weight of the newborn was less than 1.5 kg, then the risk of premature birth in the subsequent pregnancy is 50%. The causes of premature birth are multiple pregnancies, preeclampsia or eclampsia, placental abnormalities, premature rupture of the membranes (the result of an ascending uterine infection), pyelonephritis, some transmissible sexual diseases and spontaneous uterine activity. Women with previous preterm deliveries need an ultrasound examination to measure the length of the cervix, monitoring at 16-18 weeks should be done to diagnose pregnancy-induced hypertension. If symptoms of threatening premature birth progress, it is necessary to check the contractility of the uterus, tests for bacterial vaginosis; the definition of fetal fibronectin can identify women who need more careful monitoring by a physician.

Previous birth of a newborn with genetic or congenital malformations. The risk of having a fetus with chromosomal abnormalities is increased for most couples who, in previous pregnancies, had a fetus or a newborn with chromosomal abnormalities (diagnosed or undiagnosed). The risk of relapse for most genetic disorders is unknown.

Most congenital malformations are multifactorial; The risk of developing a subsequent fetus with genetic disorders is 1 % or less. If couples in previous pregnancies had a newborn with genetic or chromosomal disorders, then such pairs are shown to have genetic screening. If couples have a newborn with a congenital malformation, then ultrasonography with high resolution and examination by a specialist in prenatal medicine is necessary.

Polyhydramnios and polyhydramnios. Polyhydramnios (an excess of amniotic fluid) can lead to severe dyspnea in the mother and premature birth. Risk factors are: uncontrolled diabetes in the mother, multiple pregnancies, isoimmunization, and fetal malformations (eg, esophageal atresia, anencephaly, spina bifida). Malnutrition (amniotic fluid deficiency) often accompanies congenital malformations of the urinary tract in the fetus and a severe delay in the intrauterine development of the fetus.

Pregnancy in patients with the presence of Potter's syndrome in a fetus with lung hypoplasia or superficial compression disorders can be interrupted (usually in the 2nd trimester of pregnancy) or end in fetal death of the fetus.

Polyhydramnios or hypochlorism may be suspected in cases where the size of the uterus does not correspond to the gestational date or is found accidentally in diagnostic ultrasonography.

Multiple pregnancy. With multiple pregnancies, the risk of intrauterine fetal development delay, premature birth, placental abruption, congenital malformations of the fetus, perinatal morbidity and mortality, atony of the uterus and bleeding after childbirth increases. Multiple pregnancy is detected with conventional ultrasonography in the 18-20 weeks of pregnancy.

Previous birth trauma. Injury to the newborn during labor (eg cerebral palsy, developmental delay or trauma due to forceps or vacuum extractor, dystocia of the shoulders with Erbe-Duchenne paralysis) does not increase the risk in subsequent pregnancies. However, these factors should be evaluated and not allowed for subsequent delivery.