Preterm Labor & Preterm Birth Family Medicine Specialist CME Vientiane, Lao PDR December 10 – 12, 2008

Objectives Define preterm labor and recognize significance to infant mortality & morbidity Describe common causes of preterm labor Describe how to diagnose preterm labor Explain the management of preterm labor & preterm birth

Preterm Labor Regular uterine contractions Progressive cervical dilatation +/- effacement Less than 37 weeks gestation Usually results in preterm birth

Preterm Birth Birth occurring before 37 completed weeks of gestation Dated from Last menstrual period (LMP)

Incidence Occurs in 7 – 10% of all pregnancies Has not changed in 30 years in countries such like Canada Approximately 1 – 2% of pregnancies deliver before 34 weeks gestation

Significance Babies born >34 weeks gestation in centres with NICU have survival rates equal to babies born at term Babies born <34 weeks gestation have long term adverse outcomes –Respiratory complications –Central nervous system complications –Neurodevelopmental delays –Blindness & deafness Babies born <30 weeks gestation have high mortality and morbidity

Etiology Preterm pre-labor rupture of membranes Spontaneous preterm labor with intact membranes Other causes –Placental abruption –Chorioamnionitis –Gestational hypertension –Abnormal fetal monitoring findings –Intrauterine growth restriction

Risk Factors Prior history of spontaneous preterm birth Preterm pre-labor rupture of membranes Antepartum hemorrhage Uterine distension –Twins (multigestational pregnancy) –Polyhydramnios Incompetent uterus/uterine abnormality Fetal anomly

Risk Factors Infection –Chorioamnionitis –Bacteriuria –STI’s –Peridontal disease –Bacterial vaginosis + prior preterm birth Drugs, smoking (>10 cigs/day), lifestyle Domestic violence Demographic factors –Maternal age 35 years of life –Maternal weight <55 kg - malnourishment

Diagnosis Early –Educate patients about early signs & symptoms of preterm labor Contractions Vaginal fluid loss Vaginal bleeding Maternal perception of vaginal pressure, low dull backache, vaginal discharge

Diagnosis Establish dates of pregnancy –LMP (Last Menstrual Period) –EDD (Estimated Date of Delivery) –Current gestational age Identify risk factors Evaluate for uterine contractions Assess for cervical changes

Management Objectives Early diagnosis of preterm labor Identify & treat underlying causes of preterm labor Attempt to arrest labor, if appropriate Intervene to reduce neonatal morbidity & mortality

Prolongation of Pregnancy Use of tocolysis to prolong pregnancy for 48 hours allows: –Betamethasone treatment –Transfer of mother to appropriate neonatal centre for delivery of baby

Prolongation of Pregnancy Contraindications for continuing pregnancy –Gestational hypertension with proteinuria / adverse events for mother –Chorioamnionitis –Mature fetus –Imminent delivery –Intrauterine death or lethal fetal anomaly

Betamethasone treatment Dose: 12 mg IM for 2 doses, 24 hours apart Requires 48 hours for maximum benefit Gestational age: 24 to 34 weeks Crosses placenta and accelerates lung maturity Helps prevent intra-ventricular hemorrhage and necrotizing enterocolitis

Antenatal Steroid Cautions If immediate delivery indicated, do not delay for steroid effect If cardiac disease, active TB, chorioamnionitis, placental abruption Transient increase in WBC count

Tocolytics Some evidence for: –Nifedipine (Calcium Channel blocker) –Indomethacin (Prostaglandin Synthetase Inhibitor) Gestational age <32 weeks –Risk of fetal premature closure of ductus arteriosis 100 mg suppository PR for transport

Maternal Transport Mother should be transported to hospital best suited for delivery of neonate Requires transportation with skilled birth attendant Consider risk of delivery en route Consider risk of journey to maternal / neonatal well-being

Maternal Transportation Contraindications –Unstable mother –Abnormal fetal monitoring –Imminent delivery –Lack of skilled birth attendant to accompany mother –Weather or hazardous conditions for travel

Prevention Screen & treat for asymptomatic bacteriuria Screen & treat for STI’s Education of patients for signs & symptoms of Preterm labor

Conclusion Diagnosis preterm labor early to provide for appropriate intervention and treatment Treat with betamethasone if appropriate to enhance fetal lung maturity Use tocolysis to allow for betamethasone to work and allow for maternal transfer to appropriate hospital