Diagnosis and Management of Preterm Labor

1. Diagnosis and Management of Preterm Labor James Ducey MD Staten Island University Hospital StatenIsland Universiaty Hospital

2. Making The Diagnosis • Labor is a retrospective diagnosis • Once vaginal delivery has occurred we can be sure the woman was in labor • There are a variety of methods we use to diagnose labor • None of them are foolproof StatenIsland Universiaty Hospital

3. Clinical Factors Used to Predict Preterm Labor • Risk assessment is a concept first proposed by Papiernik (Presse Med 1969) • The hope was that identification of women at increased risk to give birth early prior to the onset of labor would lead to interventions that would prevent preterm birth StatenIsland Universiaty Hospital

4. Risk Assessment • The frequency of a large # of demographic and epidemiological markers in women who did and did not give birth were compared • Scoring systems to predict which women were at increased risk for preterm birth StatenIsland Universiaty Hospital

5. Economic • Poor • Unemployed • Father is either • Not insured • No access to care • Not well fed StatenIsland Universiaty Hospital

6. Behavioral • Poor education • Not compliant with prenatal care • Substance abuse • Old or young • Life stresses StatenIsland Universiaty Hospital

7. Medical • Mom was small at birth • Short • Underweight or overweight? • Chronic illnesses StatenIsland Universiaty Hospital

8. Obstetric • Previous preterm birth • Multiple birth • Acute infections • Hypertensive disorders of pregnancy • Uterine anomalies StatenIsland Universiaty Hospital

9. Risk Assessment • Creasy and co-workers have published a number of more simplified scoring systems(ObGyn 1980,1982,Birth Defects 1983) • Prospective studies have reported sensitivities of 40 – 60% • Positive predictive values between 15 – 30% StatenIsland Universiaty Hospital

10. History • Pain-abdominal,back,pelvic,vaginal,gas • Vaginal bleeding, staining • Pelvic pressure • Urinary frequency • Diarrhea or constipation StatenIsland Universiaty Hospital

11. History • Many normal women who deliver at term have similar symptoms • Iams etal (ObGyn 1990) reported that 1/3 of the women they studied that developed preterm labor had no symptoms at all StatenIsland Universiaty Hospital

12. Physical Examination • Asymptomatic effacement and dilation of the cervix frequently occurs prior to labor • It may be the first sign of labor, cervical incompetence or normal variation especially in multiparous women • Buekens ( Lancet 1994) in a randomized study of over 5000 women showed no difference in outcome when cervical exam was performed at every visit StatenIsland Universiaty Hospital

13. Uterine Activity • Frequency and duration of uterine contractions can be monitored accurately in an ambulatory setting • There is an increase in uterine activity in 24 hours prior to preterm labor (Katz ObGyn 1986) StatenIsland Universiaty Hospital

14. Uterine Activity • Initial studies were promising • In addition to uterine activity monitoring there was a lot of nursing contact • Much controversy ensued • May diagnose preterm labor sooner • Not clinically significant StatenIsland Universiaty Hospital

15. Biochemical Markers • Estrogen • Progesterone • Prostaglandins and their metabolites • Activan • Inhibin • Collagenase • Tissue inhibitors of metaloproteinases • Fetal Fibronectin StatenIsland Universiaty Hospital

16. Fetal Fibronectin • Component of extra cellular matrix • Lockwood (NEJM 1991) found that levels were elevated in cervicovaginal secretions in women who delivered early • AHRQ published a review of the data StatenIsland Universiaty Hospital

17. Fetal Fibronectin 7 Days <37 Weeks Sensitivity 89.4% 54.7% Specificity 83.3% 85.6% PPV 22.9% 58.8% NPV 99.3% 83.4% StatenIsland Universiaty Hospital

18. Fetal Fibronectin AT SIUH 81 Test in 71 women 20 have delivery data 13 Negatives 8 were term 5 preterm (all 35 – 36 weeks) None within 7 days 7 positives 3 were term 4 preterm (all <32 weeks) 2 within 7 days StatenIsland Universiaty Hospital

19. Endovaginal Ultrasound • Cervix visualized in great detail • Funneling of the internal cervical os • Length of the cervix • Sensitivity, specificity, positive and negative predictive values similar to fetal fibronectin StatenIsland Universiaty Hospital

20. Treatment • Surgery • Pharmacological agents • Behavioral changes StatenIsland Universiaty Hospital

21. Correction of Uterine Malformations • Women with defects in lateral fusion of the Mullarian ducts appear to be at increased risk for preterm labor • Surgery is usually reserved only for habitual abortion StatenIsland Universiaty Hospital

22. Cervical Incompetence • History of cervical trauma or surgery • Two subsequent pregnancies that terminated spontaneously in the late second or early third trimester and the loss was characterized by days of pelvic pressure followed by spontaneous rupture of the membranes and quick painless labor StatenIsland Universiaty Hospital

23. Cerclage • Has become the standard treatment • Large prospective randomized study was carried out by RCOG 1992(BJOG 1993) • A heterogeneous group of women felt to be at increased risk for preterm birth StatenIsland Universiaty Hospital

24. Cerclage • A very safe operation • There was a significant decrease in delivery prior to 35 weeks in women who under went cerclage • 25 operations to prevent 1 preterm birth StatenIsland Universiaty Hospital

25. Pharmacological Agents • Tocolytics • Glucocorticoids • Thyrotropin-releasing hormone • Antibiotics • Others StatenIsland Universiaty Hospital

26. Tocolytics • Magnesium sulfate • Beta adrenergic agonists • Prostaglandin inhibitors • Calcium channel blockers • Oxytocin-receptor antagonist • Ethanol • Progesterone StatenIsland Universiaty Hospital

27. Tocolytics • All these drugs seem to delay delivery 48 hours • None is superior in efficacy • Delay of 48 hours improves neonatal outcome when corticosteroids are used in conjunction StatenIsland Universiaty Hospital

28. Magnesium Sulfate • Maternal side effects are nausea, uncomfortable sensation of heat, weakness, pulmonary edema(1%) and respiratory arrest • Fetal side effects are hypotonia and hypocalcemia StatenIsland Universiaty Hospital

29. Beta Adrenergic Agonists • Ritodrine and Terbutaline • Maternal side effects include myocardial ischemia, pulmonary edema(4%), hypotension, tachycardia, hypokalemia, hyperglycemia and acidosis • Fetal effects include hypotension, tachycardia, hypoglycemia and hyperbilirubinemia StatenIsland Universiaty Hospital

30. Prostaglandin Synthetase Inhibitors • Indomethacin • Maternal side effects include GI upset, rash, headache and interstitial nephritis • Fetal effects include oliguria, oligohydramnios, premature closure of the ductus arteriosus and pulmonary hypertension StatenIsland Universiaty Hospital

31. Calcium Channel Blockers • Nifedipine • Maternal side effects include headache, nausea,flushing,hypotension,tachycardia and hepatotoxicity • Fetal effects are not clear StatenIsland Universiaty Hospital

32. Oxytocin Receptor Blockers • Atosiban new drug that appears to be effective • Causes nausea, headache, chest pain, arthralgias and may inhibit lactation StatenIsland Universiaty Hospital

33. Ethanol • No longer used • Caused acute intoxication in the mother • May be toxic to the fetus StatenIsland Universiaty Hospital

34. Progesterones • Has been used for many years to prevent miscarriage without proven efficacy • Keirse (BrJObGyn 1990) found that when used routinely on initial registration resulted in a significant decrease in preterm labor and birth • No effect on neonatal morbidity or mortality however StatenIsland Universiaty Hospital

35. Antenatal Steroids • Crowley etal(BrJObGyn 1990) meta-analysis of 12 controlled studies • There was a significant decrease in RDS,IVH,NEC and NND • NIH conference 1995 concluded that all women at risk for preterm birth between 24 and 34 weeks are candidates StatenIsland Universiaty Hospital

36. TRH • Knight etal (AJOG 1994)reported that adding TRH to corticosteroids improved fetal lung maturation • Crowther etal (Lancet 1995) was unable to reproduce the results and had a high incidence of hypertension develop in treated women StatenIsland Universiaty Hospital

37. Antibiotics • Several studies have looked at the use of various drugs to treat subclinical infections and prevent neonatal sepsis • Results have been inconsistent • Has not gained acceptance StatenIsland Universiaty Hospital

38. Behavioral Changes • Bed rest • Coitus • Substance abuse • Obesity StatenIsland Universiaty Hospital

39. Obesity • Will kill more Americans in the next 50 years than cancer, cigarette smoking and HIV combined StatenIsland Universiaty Hospital

40. Obesity • Schieve etal (Epid 1999) women with increased weight gain during pregnancy were at increased risk for preterm birth • Rothacker etal (ADA2000) mean weight gain of women 20 – 30 years of age from 1992 to 1997 increased 12.1 kg StatenIsland Universiaty Hospital

41. The Future • Tocolysis will only impact on <5% of preterm birth • Fetal fibronectin and/or endovaginal ultrasound needs to be used to identify objectively women for randomized studies StatenIsland Universiaty Hospital

42. The Future • Reproductive endocrinologist need to limit the # of embryos they implant • Iatrogenic prematurity continues in some places despite many of our best efforts StatenIsland Universiaty Hospital