Prematurity Module AnS 536 Spring 2015

What is Prematurity? Prematurity is defined as less than 37 weeks of gestation in humans Prior to 32 weeks is considered a very premature birth Less than 28 weeks is extremely premature

Preterm Labor Occurs prior to expected delivery date Occurs for a variety of reasons  Prelabor rupture of membranes Can lead to amnionitis Methods to prevent labor  Stop /delay onset of pre-mature births  Do not guarantee a healthy infant Planned interventions to terminate pregnancy  Serious maternal illness  Problems affecting fetal well being or growth

Preterm Labor Preterm labor prevention:  Social measures Ad campaigns increasing awareness  Smoking  Sexually transmitted diseases  Physical measures At home uterine-activity monitoring Bed rest Cervical assessment  Surgical measures Cervical cerclage

Preterm Labor Preterm labor prevention cont…  Pharmacological agents Betamimetic drugs  Stop uterine contractions in active labor  Most widely used among other labor-inhibiting agents Inhibitors of prostaglandin synthesis  Strong and practical use in preventing labor Antibiotics  Some use in preventing early labor in women with bacterial vaginosus

Preterm Labor Types of preterm births  Antepartum death  Lethal malformations Fetal outcome cannot be changed, vitality of mother is important  Multiple pregnancies 50% of all multiple pregnancies result in premature delivery  Elective deliveries  Maternal and/or fetal pathology Preclampsia Antepartum hemorrhage Intra-uterine growth restriction

Antepartum death and lethal malformations 10-15% of all premature births Almost 50% of total perinatal mortality This form is unsavable Infant dies before labor or has malformations that are incompatible with life Maternal well-being is a large factor Ethical problems come in to play

Multiple Pregnancy Almost half of multiple births occur prematurely Multiple births are 15 times more likely to be associated with premature delivery Multiple births make up 20% of all premature cases

Elective Delivery Planned obstetric decision Complications during pregnancy within the mother or the fetus Not necessarily premature infants

Maternal and Fetal Pathology Eclampsia Antepartum hemorrhage Intra-uterine growth restriction Spontaneous preterm labor

Route for Delivery Main decision for premature infants Vaginal or Cesarean Section Breech much more common in preterm Safer for premature infants to use C-section  Mostly planned deliveries Premature baby is more susceptible to compress from the pelvic region than a term baby  They have a softer skull

Preterm Birth Physiological consequences  Infant’s body system are not prepared to function on their own  Numerous conditions that result from prematurity can be treated  Depending upon extent of prematurity, morbidity rate may be great

Preterm Birth Preterm birth is the leading cause of neonatal mortality  Lack of development of body systems is underlying cause Concerns:  Increased morbidity and mortality  Intraventricular hemorrhage (IVH)  Periventricular leukomalacia (PVL)  Cerebral palsy  Necrotizing enterocolitis (NEC)  Retinopathy of prematurity (ROP)  Respiratory distress syndrome (RDS)

Preterm Birth Complications Respiratory distress syndrome Affects over 50% of premature infants One of leading cause or mortality and morbidity Ventilator needed in some cases Use different techniques to speed up pulmonary maturation or assist lung function

Preterm Birth Complications Corticosteroids  betamethasone and dexamethasone Reduce risk of RDS by 40-60% Speeds up lung maturation Max effect more than 24 hr prior to birth within 7 days of administration Risks to corticosteroids  Increased susceptibility to infection

Renal System Decreased ability to maintain blood pressure Difficult time regulating electrolyte and water balance

Neurological Developmentally behind slightly Intraventricular hemorrhage  Blood vessels of brain not fully developed  Premature infants at a much higher risk  Increase risk if other problems  No prevention Hydrocephalus  Fluid accumulation in the brain

Neurological Periventricular leukomalacia  Contributing factors: Premature infant brains very fragile Lack of oxygen Early rupture of fetal membranes Infection inside the uterus  No treatment for this condition

Thermoregulation Tend to lose body heat rapidly Less stored fat At high risk to hypothermia  Leads to breathing problems and low blood glucose Use available energy for heat  Hypoglycemia  Decreased stores of glycogen

Gastrointestinal and Metabolism Immature systems Necrotizing enterocolitis  Cells in bowel are injured  Infants fed only breast milk have lower risk Spontaneous intestinal perforation

Immunity Increased susceptibility to infection through childhood Risk of bacterial infection  Prolonged intensive care  NICU environment Immunoglobulin G deficiency at birth

Immunity cont. Slower development of innate immune defense Prematurity affects all aspects of immunity  Immune signaling  Link between adaptive and innate immunity Limited neutrophil precursor pool  Neutropenia Increase bacterial infections

Long Term Cerebral palsy  40-50% of patients were born prematurely  Affects movement and muscle tone  Results from CNS damage Poor circulation Insufficient oxygen and nutrient supply Neural infection Impaired cognitive skills  Lag behind full-term babies in mental development  More likely to have a learning disability

Long Term Cont. Vision problems  Retinopathy of prematurity Blood vessels swell and overgrow in the light sensitive layer of the nerves of the retina  Retinal scarring  Retinal detachment Possible blindness Hearing problems  Increased risk of hearing loss

Long term cont. Dental problems  Delayed tooth eruption  Tooth discoloration  Improper alignment of teeth Behavioral and psychological problems  More likely to develop problems  Attention deficit hyperactivity disorder (ADHD)  Depression or anxiety  Interaction issues

Long term cont. Chronic health issues  Infections  Asthma  Feeding problems  Sudden infant death syndrome Possible risk of diabetes and cardiovascular disease

Preterm Birth Cerebral palsy  Condition where infants are unable to control muscle movement  Muscles become tight and uncontrolled  No treatment for this condition Necrotizing enterocolitis  Occurs 3 to 7 days after onset of feeding  Premature infants react abnormally to diet  Bowels become inflamed and spontaneously necrose  Treatment: Surgical treatment if bowel is perforated Feedings are withdrawn Contents of stomach are suctioned out

Developmental Outcomes for Premature Infants Rate of premature births has increased  ↑ by 29% from 1981 to 2002 Survival rate of premature infants reaching adulthood has also increased Can be severe consequences of prematurity