Preterm Labor & Preterm Birth

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

2. 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

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

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

5. 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

6. 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

7. 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

8. 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

9. 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 <18 or >35 years of life • Maternal weight <55 kg - malnourishment

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

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

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

21. 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