Management of Actual Preterm Labor and Delivery (APTL)
WHO definition: Preterm labor is the presence of contractions of sufficient strength and frequency to effect progressive effacement and dilation of the cervix between 22 and 37 weeks' gestation.
Diagnostic criteria to document APTL(20-37w):
- 4 contractions during 20 minutes
- Cervical dilation >2 cm in nullipara and >3 cm in multipara
- Cervical effacement >80%
The main clinical symptoms are: regular labor pains, cervical dilation for more than 3 cm. Early rupture of membranes, abnormalities of labor pains (weakness, excessive pains, incoordinated pains), intrauterine hypoxia, hemorrhages are characteristic too.
The principles of management of preterm labor are:
- to prevent fetal distress which makes the baby more susceptible to respiratory distress syndrome;
Management of the First stage of Preterm labor: the patient is taken to bed to prevent early rupture of amniotic membranes. A sedative and analgesic therapy should be avoided to prevent depression of the fetal respiratory centre. Therapy to prevent failure of placental microcirculation should be prescribed. Labor should be watched by intensive electronic monitoring. In case of abnormalities of labor pains a special treatment should be administered. If necessary, acceleration of labor by a low rupture of membranes and/or oxytocin infusion should be performed. In case of delay or anticipating a traumatic vaginal delivery, a caesarean section is indicated.
Management of the Second stage of Preterm labor: accurate control of cardiac activity of the fetus, control of uterine contractile activity, prevention of fetal distress. Caesarean section is performed in the presence of obstetric indications. The air passage should be cleared of mucus just after the delivery of head to prevent inspiration of contents and development of asphyxia, atelectasis, pneumonia. The cord is to be clamped immediately at birth to prevent the development of hypervolemia and hyperbilirubinemia.
Premature Infant. A baby born before 37 completed weeks of gestation calculated from the first day of last menstrual period is arbitrarily defined as preterm baby. Babies born before 37 completed weeks usually weigh 2,500 g and less, the body length is 47 cm and less. The length is more important for diagnosis of prematurity than body weight. It is known that the baby may weigh more than 2,500 g even when born before 37 completed weeks. On the other hand, baby’s weight may be less than 2500 g even when born after 37 completed weeks of gestation.
Clinical signs of prematurity. The clinical manifestation differs with the degree of prematurity. There are 4 degrees of prematurity:
1st degree — 37-35 weeks of gestation, 2nd — 34-32 weeks, 3rd –31-29 weeks, 4th- less than 29 weeks of gestation. The head and abdomen are relatively large; the skull is soft with wide sutures and posterior fontanelle. The head circumference disproportionately exceeds that of the chest. Normally, the head circumference is larger than the chest circumference at birth and the difference is about 1.5 cm. The skin is thin, red and shiny, due to lack of subcutaneous fat and covered by plentiful lanugo and vernix caseosa. Muscle tone is poor. The testicles are undescended; the labia minora are exposed because the labia majora are not in contact. There is a tendency of herniation.
The nails are not grown right up to the finger tips. Immaturity of organs and systems and physiological mechanisms is a common sign of premature babies. That is why a premature infant is not stable to harmful effects, such as infection, premature anemia, cyanotic attacks. One of the main common and dangerous complication is respiratory distress syndrome (RDS) of a newborn. It is one of the major causes of death in preterm babies born before 34 weeks. RDS almost always occurs in newborns born before 37 wk of gestation: the less term of gestation is, the greater the chance of developing RDS is.
The deficiency of lung surfactant, i.e. lecithin and phosphatidyl glycerol, is the principal factor responsible for pulmonary atelectasis leading to hypoxia and acidosis. Rapid, labored, grunting respiration usually develops immediately or within a few hours after delivery, accompanied with suprasternal and substernal retractions and intercostal retractions. The expressiveness of ateletasis and severety of respiratory failure progressively increase.
The infant becomes hypoxemic, resulting in metabolic acidosis. If untreated, a severe hypoxemia can result in multiple organ failure and death. However, if the newborn’s ventilation is adequately provided, surfactant poduction will begin and RDS will resolve in 4 or 5 days. Pulmonary surfactant instilled intratracheally reduces the severity of RDS rapidly. Surfactant may be administred immediately after birth to preterm newborns judged to be at a very high risk of developing RDS. Repeated doses of exosurf can be given as needed 12 h apart (up to 3 doses).
Special care is needed for the survival of preterm babies.
The principles that are to be taken for the babies’ special care are:
- to maintain a relatively constant body temperature
- to prevent or to treat atelectasis
- to prevent infection
- to maintain nutrition
- adequate nursing care.
Date added: 2022-12-25; views: 263;