Preterm labor and Prematurity Asheber Gaym M.D. January 2009

Outline  Definition of preterm labor  Discuss etiology of preterm labor  Describe be diagnosis of preterm labor  List complications of preterm labor  Outline management of preterm labor 2Asheber Gaym,2009

Definitions and Epidemiology  Preterm labor- onset of labor before 37 completed weeks and after the 20 th week of pregnancy.  Affects 10% of pregnancies on average.  Preterm labor is the commonest cause of preterm birth which leads to the prematurity, responsible for 80-90% of perinatal mortality in the developed world. This makes prevention of preterm labor a major focus of obstetric care is these settings.  Early diagnosis, short term tocolysis and appropriate management of delivery assist to reduce perinatal morbidity and mortality.  Preterm birth results from preterm labor and delivery or preterm pregnancy termination as part of the management of high risk of pregnancies. 3Asheber Gaym,2009

Etiology of Preterm Labor – Risk Factors MaternalFetalOthers  PROM  Antepartum hemmorhage  Past history of preterm labor  Pre eclampsia/eclampsia  Uterine myoma  Smoking  Cocaine, heroin use  Anemia  RH Isoimmunization  Low socioeconomic status  Sexually transmitted infections  Multiple pregnancy  Polyhydramnios  Idiopathic – majority  Subclinical chorioamnionitis  Iatrogenic- CST, ECV, Amniocentesis, PUBS Asheber Gaym,20094

Diagnosis of Preterm Labor  Confirmed Gestational Age <37 completed weeks and  Regular, painful, rhythmic uterine contractions recurring at least twice in 20 minutes plus  A cervical dilatation of at least 2 cms or  Ruptured membranes or  Cervical effacement of > 80% or  Documented cervical change during follow up Asheber Gaym,20095

Complications of Preterm Labor MaternalPerinatal (Complications of Prematurity)  Increased risk of caesarean delivery  Complications of tocolytic drugs  Respiratory Distress Syndrome  Intraventricular hemmorhage  Necrotizing enterocolitis  Retrolental fibroplasia  Bronchopulmonary dysplasia  Feeding problems ( absence or reduced sucking reflex)  Neonatal infection and sepsis – reduced resistance to infection  Birth trauma  Hypothermia  Hypoglycemia, hypocalcaemia, hypomagnesaemia, hyperbilirubinemia  Perinatal asphyxia  Long term neurologic sequel Asheber Gaym,20096

Outline of Management of Preterm Labor Manageme nt Specifics for preterm delivery General labor managemen t Same as any labor management TocolysisCervix <4 cms, fetal well being ok, no fetal distress, immature fetus tocolytic drugs may be administered to delay labor for as long as possible. Could be short term tocolysis for few days until lung maturation agents are administered or long term tocolysis if successful. Intrapartum fetal well being monitoring More intensive as the risk of fetal distress and asphyxia is higher than term labor. Atraumatic vaginal delivery The risk of fetal trauma during delivery is much higher for the preterm fetus. Thus all attempts must be made to effect an atraumatic delivery including a generous episiotomy; prophylactic forceps delivery; avoid ventouse delivery and gentle handling during delivery. Steroid administrati on If short term tocolysis is successful, steroid administration reduces the risk of RDS and IVH from weeks gestation Asheber Gaym,20097

Outline of Management of Preterm Labor ManagementSpecifics for preterm delivery Neonatal Intensive Care Should be arranged beforehand. Delivery should be effected in a facility with NICU. Preferably referral should be of the mother before delivery rather than referring a premature neonate Traditional management techniques Bed rest Fluid rehydration- 1-2 L of crystalloid/colloid administered Analgesics/sedatives administration Choice of tocolytic agents 1 st line – Beta mimetics (e.g. Ritodrine ); Magnesium sulphate 2 nd line- Prostaglandin synthase inhibitors (e.g. Indomethacine) ; Smooth muscle relaxants ( e.g. Nifedipine) Asheber Gaym,20098