Premature birth
Last reviewed: 23.04.2024
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
According to WHO, preterm birth is the birth of a child from 22nd to 37th full week of pregnancy (ie 259 days from the day of the onset of the last menstrual period). The trigger mechanisms are premature rupture of membranes, infection and pathology of pregnancy. The diagnosis is made on the basis of clinical data.
Treatment includes bed rest, the appointment of tocolytics (if pregnancy is prolonged) and glucocorticoids (if the gestational age is less than 34 weeks). Prescribe antistreptococcal antibiotics, without waiting for negative results of crops. Premature birth may be caused by premature rupture of the membranes, chorioamnionitis, or ascending uterine infection; The most common cause of such infections are Group B streptococci. Premature birth can begin with multiple pregnancy, pre-eclampsia or eclampsia, placental disorders, pyelonephritis or in some sexually transmitted diseases; often the cause is unknown. To confirm the causes identified in clinical studies, perform the crop from the cervical channel ,.
In our country premature birth is considered to be the birth of a child from the 28th to the 37th week of pregnancy (from 196 to 259 days from the start of the last menstruation). Spontaneous termination of pregnancy in the period from 22 to 27 weeks is allocated in a separate category, not related to premature birth, and the child's data in case of death do not contribute to the rates of perinatal mortality if he did not live 7 days after birth, which causes certain differences in statistical data Russian and foreign authors.
ICD-10 code
- 060 Premature delivery.
Epidemiology of premature birth
The frequency of preterm birth is 7-10% of all births, and according to the American authors, 9-10% of children are born before the 37th week, 6% - until the 36th week, 2-3% - until the 33rd week . The causes of perinatal mortality in 50-70% of cases are complications caused by preterm labor [4, 53]. Over the past 30 years, the birth rate of premature infants has remained stable, but there has been an improvement in the prognosis for newborns due to the development of neonatal medicine.
In the foreign literature, groups of newborns are distinguished:
- with a body weight from 2500 to 1500 g - low birth weight infants (LBW);
- with a body weight of less than 1500 g - very low birth weight infants (VLBW);
- with extremely low body weight, which constitute a risk group for paralysis, severe neurological disorders, blindness, deafness, dysfunctional disorders in the respiratory, digestive and genitourinary systems, and are characterized by the highest mortality.
According to the American authors, 50% of neonatal losses are recorded among newborns weighing less than 2500 g, which is only 1.5% of all children born. According to the British authors, the survival rate of children born with a body weight of less than 1500 g, due to the success of the neonatal service is about 85%, but 25% of them have severe neurologic disorders, 30% - hearing and vision disorders, 40-60% have difficulties in process of education and education.
The risk factors for premature birth include a low socioeconomic level of a woman's life, age (under 18 and over 30), unfavorable working conditions, intensive smoking (more than 10 cigarettes a day), drug use (especially cocaine), obstetric history some premature births in the anamnesis increase the risk of their occurrence during subsequent pregnancy 4 times, 2 premature births - 6 times.
Complications contributing to the development of premature birth:
- intrauterine infection (chorioamnionitis);
- premature discharge of amniotic fluid, accompanied by or without chorioamnionitis;
- isthmic-cervical insufficiency;
- abruption of normal or low-lying placenta;
- factors leading to uterine overgrowth (polyhydramnios, multiple pregnancies, macrosomia in diabetes);
- malformations of the uterus, myoma of the uterus (violation of spatial relationships, ischemic degenerative changes in the node);
- infection of the upper urinary tract (pyelonephritis, asymptomatic bacteriuria);
- surgical operations during pregnancy, especially on the organs of the abdominal cavity;
- injuries;
- extragenital diseases that disrupt the metabolic processes in the pregnant woman and lead to intrauterine fetal distress (arterial hypertension, bronchial asthma, hyperthyroidism, heart disease, anemia with a hemoglobin level less than 90 g / l);
- drug addiction, intensive smoking.
About 30% of all cases of spontaneous preterm labor are due to infection, and among 80% of children born before 30 weeks of gestation, histologically verified chorioamnionitis is noted in 80% of cases.
[Classification of preterm labor
Spontaneous premature delivery
In terms of the tactics of labor, it is important to distinguish between spontaneous premature births, beginning with regular labor for a whole fetal bladder (40-50%), and premature births starting with the discharge of amniotic fluid in the absence of labor (30-40%).
Induced preterm labor (20%)
Occur in situations requiring the completion of pregnancy as indicated by the health of the mother or fetus. Indications from the mother are related:
- with severe extragenital pathology, in which prolongation of pregnancy is dangerous for a woman's health;
- with complications of pregnancy: severe course of gestosis, hepatosis, multiple organ failure, etc.
Indications from the fetus:
- malformations of the fetus incompatible with life;
- antenatal fetal death;
- progressive deterioration of the fetus according to KTG, Dopplerometry, requiring delivery, resuscitation and intensive care.
Diagnosis of preterm labor
Allocate menacing, beginning and started premature birth.
In case of threatening premature birth the woman complains of drawing, aching pains in the lower abdomen and lower back, sensation of pressure, vaginal discharge, crotch, rectum, possibly painful urination, which may be a sign of low position and pressure of the presenting part. Regular labor is not available, individual uterine contractions are recorded. Excitability and tone of the uterus are increased.
Vaginal examination: the cervix is formed, the length of the cervix is more than 1.5-2 cm, the external pharynx is either closed or in the re-parenting women passes the tip of the finger, in some cases the lower uterine segment is stretched by the presenting part of the fetus that is palpated in the upper or middle third of the vagina .
Ultrasound: the length of the cervix is 2-2.5 cm, the cervical canal is widened to no more than 1 cm, the fetal head is located low.
How to recognize premature births?
In our country, threatening premature birth is recognized as an indication for hospitalization.
In the case of the possibility of prolonging pregnancy, treatment should be directed, on the one hand, to suppress the contractile activity of the uterus, and on the other hand, to the induction of ripening of the fetal lung tissue (in the period of 28-34 weeks of pregnancy). In addition, it is necessary to correct the pathological process, which caused premature birth.
To stop tonic and regular contractions of the uterus use complex treatment and individual selection of therapy, taking into account the obstetrical situation.
Treatment of premature birth
Prescribe antibiotics effective against group B Streptococcus, without waiting for the results of the crops. The drug of choice is benzylpenicillin 5 million ED intravenously, followed by the introduction of 2.5 million units every 4 hours; Patients with an allergy to benzylpenicillin are prescribed clindamycin at 900 mg intravenously every 8 hours.
Premature births can be stopped in 25% of women with premature rupture of membranes and in 50% without rupture of membranes. It is enough to use bed rest, hydration and antibiotics. If there is an expansion of the cervix, then the appointment of tocolytics (drugs that stop the contraction of the uterus) can stop delivery for at least 48 hours. The drug of choice may be magnesium sulfate, which most patients tolerate well. Assign a drug terbutaline 0.25 mg subcutaneously (can be repeated once in 30 minutes) every 4 hours until cessation of uterine contractions; the maximum dose of 0.5 mg / 4 hours. Terbutaline is effective in 70-80% of women; however, when taking this medication, monitoring of tachycardia is necessary. Ingestion of terbutaline is not effective. If the gestation period is less than 34 weeks, the patient is prescribed glucocorticoids: betamethasone sodium phosphate in combination with a suspension of betamethasone acetate at a dose of 12 mg intramuscularly every 24 hours 2 doses or dexamethasone at a dose of 6 g intramuscularly every 12 h 4 doses if the delivery can be delayed. These drugs accelerate the maturation of the fetal lungs and reduce the risk of developing a respiratory distress syndrome, intracerebral bleeding in newborns and death.
How to prevent premature birth?
Prenatal monitoring of the pregnant woman, timely diagnosis and correction of the resulting disorders (treatment of infection, Isthmiko-cervical insufficiency, thrombophilia, compensation of extragenital pathology) in order to prevent the birth of a prematurely born child.