What is Premature Birth?
The duration of most pregnancies is usually about 40 weeks but it is quite normal for a baby to be born a week or two earlier. However, when a baby is born before 37 weeks of gestation, it is said to be a premature birth and such babies are known as premature babies or preemies. Prematurity is a leading cause of perinatal mortality and morbidity.
Premature babies born around 36 to 37 weeks of gestation may be relatively free from complications, whereas those born much before the due dates are more likely to have serious problems which may require management in the neonatal intensive care unit (NICU). Babies born before 24 weeks have less of a chance of survival. Complications usually arise as a result of immaturity of the lungs and other organs which have not yet developed fully at the time of birth and which may not be ready to function outside the uterus.
Early and regular prenatal care can reduce the risk of a premature birth.
Causes of Premature Birth
Premature birth can occur due to various causes, some associated with the mother, others associated with the baby, and still others that may be linked to both the mother and the baby. Sometimes, no cause can be found.
Some of the reasons for a premature birth include :
- Uterine over-distension due to multiple pregnancy, such as twins or triplets.
- Cervical incompetence
- Abruptio placentae – premature separation of the placenta from the uterine wall.
- Placenta previa – low lying placenta which may block the birth canal.
- Chorioamnionitis – infection of the placenta.
- Uterine abnormalities
- Polyhydramnios – an excess of amniotic fluid in the sac.
- Pre-eclampsia and eclampsia – high blood pressure in pregnant women that may associated with kidney dysfunction and excessive fluid retention.
- Urinary tract infection (UTI) and other infections such as bacterial vaginosis (vaginal infections)
- Sexually transmitted diseases
- Premature rupture of membranes
- Trauma – accidental (car accident or fall from stairs), or intentional (domestic violence).
- Congenital birth defects in the baby.
- Labor may be induced early or an early cesarean section done in presence of complications so as to prevent harm to mother or baby.
Certain risk factors may contribute to a premature birth. This does not mean that every pregnant mother with a risk factor will definitely experience preterm labor. However, the chances are greater with one or more of the following risk factors.
- Diet – poor maternal nutrition, including eating disorders and excessive dieting or fasting.
- Age – teenage pregnancy or maternal age over 35.
- Sex – female premature babies seem to have increased survival rates than male babies.
- Previous premature birth.
- Serious maternal conditions, such as heart disease, kidney disease, severe hypertension and diabetes.
- Alcohol use.
- Drug abuse – narcotics or prescription medication.
- Multiple miscarriages.
- Inadequate and late prenatal care.
- Short interval between pregnancies.
- Conceiving through in vitro fertilization.
Several of these factors are more often associated with people of a lower socioeconomic status and this may be considered as a risk factor on its own.
Complications of Premature Birth
Prematurity is a major cause of infant death. Not all premature babies, however, develop complications. As a rule, the earlier the baby is born before the due date, the greater are the chances of complications. Usually, babies born between 32 and 37 weeks do well after birth and develop normally thereafter. Other factors that may be linked with development of complications are baby’s birth weight, presence of congenital birth defects, and maternal medical disorders during pregnancy.
- Apnea of immaturity – inconsistent breathing with short periods of total cessation of breathing – due to immaturity of that part of the brain that controls regular breathing.
- Brain hemorrhage – bleeding in the brain or intracranial hemorrhage.
- Feeding problems – inability to feed orally.
- Inability to maintain body heat – problem with body temperature control.
- Respiratory distress syndrome due to lung immaturity.
- Hyperbilirubinemia (high levels of bilirubin) leading to jaundice.
- Low blood pressure.
- Necrotizing enterocolitis – causing part of the intestine to become severely damaged.
- Due to underdeveloped immune system, premature infants are more vulnerable to infections.
- Impaired salt and water regulation due to underdeveloped kidneys.
- Difficulty in blood sugar regulation leading to hypoglycemia.
Long Term Complications
Long term complications are more likely in babies born before 26 weeks of gestation or in babies with very low birth weight.
- Delayed milestones of growth and development.
- Delayed mental growth.
- Mental or physical disability.
- Behavioral problems.
- Learning disorders.
- Cerebral palsy.
- Chronic lung disease or bronchopulmonary dysplasia.
- Retinopathy of prematurity and vision loss.
- Hearing impairment.
- Sudden infant death syndrome (SIDS) is more common in premature infants.
- Congenital heart defects, such as patent ductus arteriosus.
Prevention and Management
Early and regular prenatal care can help to prevent premature birth by diagnosing pregnancy complications early and providing timely treatment. A healthy lifestyle, including a proper diet, and avoiding smoking, drinking, and drugs during pregnancy can be helpful in preventing premature birth.
Rest may be advised to prevent premature contractions of the uterus. Tocolytics are drugs that are given to stop or slow uterine contractions for a short time in case of preterm labor. During this time, corticosteroids, such as betamethasone, may be given to develop lung maturity so as to reduce the risk of respiratory distress syndrome in the newborn, as well as to reduce the risk of brain hemorrhage (bleeding in the brain).
- Premature babies with severe complications are best managed in the NICU or special care baby unit (SCBU).
- Vital signs, such as respiration and heart rate, need to be monitored.
- A pediatrician should be available to manage any of the complications that may arise.
- Feeding intravenously or through a feeding tube is usually necessary until the baby’s suckling reflex develops.
- Breast milk should be given as soon as possible. Breast milk decreases the risk of developing necrotizing enterocolitis.
- Hospital stay will depend upon the condition of the premature baby at birth and the improvement rate.