Premature birth is delivery at the gestation period from 28 to 37 weeks, accompanied by the birth of a premature and physically immature fetus weighing 1000-2500 g and 35-45 cm long. Condition can be threatening, incipient and incipient. Depending on this, the clinical manifestations and obstetric tactics in preterm labor will be different. With threatening and incipient childbirth, they tend to prolong pregnancy. Preterm labor that has begun with the development of regular labor activity is carried out under the control of the condition of the mother and fetus.
ICD 10
O60 Premature birth
General information
Premature birth ends in 5-12% of pregnancies. According to the WHO definition, termination of pregnancy at 22-28 weeks, ending with the birth of a fetus weighing 500-1000 g and having lived for at least 7 days, is considered as early premature birth with extremely low fetal weight. If a child born from premature birth dies before the 7-day period, such an outcome of pregnancy is regarded by obstetrics and gynecology as a late miscarriage.
Premature birth is always associated with high risks of complications for the newborn. Premature birth, developing at 22-27 weeks, is prognostically less favorable in terms of fetal viability, since by this time the newborn’s lungs have not yet reached the necessary degree of maturity to ensure respiratory function. The outcome of premature birth at 28-34 weeks or more of pregnancy is potentially more favorable for the newborn.
Causes
Premature birth can be caused by reasons related to the health of the pregnant woman, the condition of the fetus, the course of pregnancy, socio-biological conditions. Among the “maternal” factors, STDs (mycoplasmosis, chlamydia, ureaplasmosis, herpes, cytomegalovirus infection, etc.), acute viral lesions (rubella, influenza, viral hepatitis, etc.), chronic pathology of a pregnant woman (tonsillitis, pyelonephritis, heart defects, diabetes mellitus, hypertension), endocrinopathy (Addison’s disease, Cushing’s syndrome, hypothyroidism, obesity).
The full-term pregnancy largely depends on the state of the reproductive organs. Condition is often found in women with diseases and abnormalities of the uterus – endometriosis, fibroids, uterine hypoplasia, bicornuate uterus, intrauterine septum, intrauterine synechiae. The development of cervical insolvency leading to premature birth is facilitated by damage to the uterus during diagnostic curettage, artificial abortions and childbirth, operations (conization, amputation of the cervix), etc.
The causes of premature birth caused by the condition of the fetus include, first of all, genetic disorders, severe congenital anomalies, malformations, intrauterine diseases (hemolytic disease) and fetal infections. In some cases, an invasive prenatal diagnosis – cordocentesis, amniocentesis – can lead to premature birth.
The so-called combined factors associated with the course of pregnancy include immunological conflicts (Rh conflict), gestosis, placenta previa or its premature detachment, transverse fetal position, pelvic presentation, multiple pregnancy and childbirth, etc.
The frequency of premature birth directly depends on the socio-biological conditions in which pregnancy occurs. Premature birth can be provoked by hard physical labor, excessive mental stress, stress, poor nutrition, bad habits.
Symptoms of premature birth
According to the clinical course, premature birth can be threatening, beginning and beginning. When determining the stage of premature birth, they are guided by an assessment of the contractile activity of the uterus, the condition of the fetal bladder and the birth canal. In the case of a threatening nature of premature birth, a pregnant woman has aching, pulling pains in the lower back and abdomen, tension of the uterus and its contractions, an increase in fetal motor activity is noted, sometimes – sucre discharge from the genital tract. Such symptoms require urgent treatment to an obstetrician-gynecologist.
For the beginning of premature labor, pronounced abdominal pain, regular contractions, a symptom of the discharge of the cervical plug, the appearance of blood secretions, often – leakage or outpouring of amniotic waters are typical. With the onset of premature labor, regular labor activity develops with an interval between contractions of less than 10 minutes, there is a sucre discharge, there is a lowering of the adjacent part of the fetus to the entrance to the pelvis and rupture of the fetal bladder.
In general, premature birth is characterized by untimely outpouring of water; weak, sometimes strong or discoordinated labor; rapid or prolonged course; placental abruption and bleeding; postpartum complications; fetal hypoxia.
Diagnostics
To establish the fact of premature birth and its stage, an important criterion is the assessment of the state of the cervix and fetal bladder. Vaginal examination and examination of the cervix in mirrors is carried out to determine the degree of opening of the uterine pharynx, the length and consistency of the cervix. In case of threatening childbirth, the examination reveals an unchanged cervix, a closed external uterine pharynx; with the beginning of labor, the cervix is shortened, the uterine pharynx is slightly open by 1-2 cm; with the beginning, the smoothing of the cervix and the opening of the uterine pharynx is determined by 2-4 cm. Gynecological examination should be repeated in dynamics after 30-60 minutes.
In order to exclude urogenital infections and latent bacteriuria, a back-seeding of the discharge from the cervix for pathogens (staphylococcus, chlamydia, ureaplasma, gonococcus) and a bacteriological examination of urine is carried out. With the help of ultrasound, the gestation period, the estimated weight of the fetus, its position and presentation, the integrity of the fetal bladder, the condition and localization of the placenta are specified, placenta previa is excluded. Auscultation and instrumental recording of fetal heartbeat (fetal phonocardiography, cardiotocography) in preterm labor are necessary to detect signs of hypoxia.
Additionally, in order to determine the obstetric status, the Baumgarten tocolysis index is used, calculated by the sum of points obtained when evaluating a number of objective parameters (the presence of contractions, rupture of membranes, bleeding, opening of the cervix). At the same time, the lower the score, the more effective tocolytic therapy can be.
In some cases, with a slow opening of the cervix, premature birth needs to be differentiated from the pathology of the urinary tract and abdominal organs: pyelonephritis, cystitis, urolithiasis, gastroenteritis, spastic colitis, acute appendicitis.
Treatment
If premature birth is suspected, immediate hospitalization of the pregnant woman in an obstetric hospital is necessary. If, with the threatening or incipient nature of premature birth, the tactics of prolonging pregnancy are permissible, then in the case of early labor, leakage of amniotic fluid, signs of infection or severe extragenital diseases, active labor management is resorted to.
Therapy for threatening and incipient premature birth requires the appointment of bed rest, sedatives (motherwort, valerian, diazepam) and antispasmodics (drotaverine, metacin, papaverine); physiotherapeutic effects – electrical relaxation of the uterus (amplipulstherapy), electroanalgesia, acupuncture.
Glucocorticoid drugs (dexamethasone, prednisone, betamethasone) are prescribed in order to accelerate the maturation of fetal lung tissue and prevent respiratory failure of a newborn with the threat of premature birth up to 34 weeks of pregnancy. Glucocorticoid therapy is contraindicated if a pregnant woman has gastric or duodenal ulcer, endocarditis, circulatory insufficiency of the III art., nephritis, active tuberculosis, osteoporosis, severe forms of diabetes mellitus, gestosis.
Conducting tocolytic therapy allows you to achieve the removal of contractile activity and uterine tone. In preterm labor, the administration of magnesium sulfate, beta-mimetics (ipratropium bromide, terbutaline, phenoterol, etc.), prostaglandin inhibitors (naproxen, indomethacin) is indicated. Prevention of fetal hypoxia and placental insufficiency is carried out by the appointment of dipyridamole, pentoxifylline, vitamin E.
When streptococcal, gonococcal, chlamydial infections, bacterial vaginosis, trichomonas vulvovaginitis are detected, antimicrobial therapy is prescribed. In case of detection of cervical insufficiency, a special ring is applied to the cervix – the introduction of an obstetric pessary, according to indications (with insufficient function of the adrenal glands and thyroid gland) – hormonal correction.
Management of premature birth
Taking into account the obstetric situation, the management of preterm labor that has begun can be expectantly conservative or active. In the first case, the course of labor is monitored without the provision of special obstetric benefits. More often, with premature birth, there is a need for active intervention in the course of natural childbirth or cesarean section.
The tactics of conducting early labor are influenced by the gestation period, the stage of labor, the condition of the fetal bladder, the degree of cervical dilatation, the presence of infection, the severity of labor, the presence and nature of bleeding. The management of premature birth is accompanied by constant cardiac monitoring.
30% of premature births occur abnormally – with excessive, weak or discoordinated labor activity. Therefore, in the management of preterm labor, antispasmodic drugs, epidural anesthesia in childbirth are widely used. In case of excessive labor, drugs are administered that restrain the contractile activity of the uterus; in case of weakness of the labor forces, rodostimulation is performed. In order to protect the fetus when passing through the birth canal, they resort to dissection of the perineum – perineotomy.
Indications for cesarean section in premature birth are severe pathology of the mother and fetus, pelvic presentation of the fetus. After the birth of a premature fetus, if necessary, the entire volume of resuscitation measures is immediately started.
Complications
In children born from premature birth, due to the immaturity of all anatomical structures, the presence of birth injuries (intracranial hemorrhages, injuries of the cervical spine); hypoxia; functional unavailability of the lungs is often noted. For a woman, premature birth can be complicated by ruptures and injuries of the cervix, postpartum bleeding, infections (suppuration of sutures, postpartum metroendometritis, peritonitis, sepsis).
Prevention
When planning a pregnancy, all women are recommended to undergo a full examination by a gynecologist and narrow specialists to exclude potential risk factors. Early registration and management of pregnancy under the supervision of an obstetrician-gynecologist contributes to the prevention of premature birth. Special medical control is required by pregnant women at risk for the development of premature birth – women with sexual infantilism, menstrual disorders, endocrinopathies, habitual miscarriage, chronic infections, IVF survivors, Rh-negative blood, etc. d.