Screening for preterm labour?

1. Screening for preterm labour? Yves Jacquemyn UZA UA

2. Screening for preterm labour? Yves Jacquemyn UZA UA

3. Screening to prevent preterm labour? Yves Jacquemyn UZA UA

4. What is preterm labour/birth? New dogma says….

5. Modern dogma? • Only < 34 weeks matters!

6. Modern dogma? • Only < 34 weeks matters! • Is that so?

7. Late preterm and preterm births in flanders % (SPE)

8. Perinatalmortality in flanders ‰ (spe)

9. Late preterm = 10 x mortalityvs term!

10. morbidity

11. Flanders: 5x N* (%)

12. Flanders : 2x respiratoryproblems (%)

13. Flanders : nodifference in infections

14. Flanders: 2x intracranialbleeding (%)

15. Beingbornbetween 34(2) 0/7 and 36 6/7 means: • Is the majority of preterms • Is the major burdenfor the health system • More and longerhospitalisation • More respiratoryproblems • More intracranialbleeding • more hypoglycemia; temperatureinstability, jaundice • And later….

16. Long term outcomes late preterm • More cerebral palsy ( RR 2.7) • Mental retardation (RR 1.6) • Evelopmental problems • Blindness, decreased vsion, hearing loss • Less likely to attain higher education Ramachandrappa et al 2012

17. Prolonging pregnancy is probably not the aim! Eliminating risk factors canbe!

18. Screening for this talk means: • Low risk obstetric population • No previous ptb • asymptomatic To allow real primary prevention!

19. Preterm labour/ delivery have multiple causes • Multiple tests usedfor different etiologies • We needsomeclassification system ( Goldenberg et al, AJOG 2012)

21. Different etiologies different tests Home uterine activity monitoring Hormonal tests in maternal blood Blood biochemistry for placental factors Vaginal pH, cultures Ultrasound cervical length Vaginal biochemistry, FFN et al

22. Different tests lead to different interventions Rest / tocolysis Rest, progesterone Aspirine? Lactobacilli/ antibiotics Porgesterone/ cerclage Progesterone/ nsaid?

23. And it all results in complicated prediction models Eg Lee et al J Womens Health 2011: bayesian filtering

24. The interventions are worth another talk

25. When to consider a test worthwile? a significant changefrom pre test to post test probability

26. Likelihood ratio

29. When to consider a test worthwile? • Likelihood ratio for positive test > 10 • LR for a negative test < 0.1 • = convincing • Pos LR 5-10 • NLR 0.1-0.2 • = moderate prediction

30. In low risk asymptomatic women • Only • Ultrasonographic cervical length • Saliva estriol (+LR =5, Hee Acta ob sc 2011) • Have +LR >5 • (Honest et al, Health Technol Assess, 2009) • None of the newer biomarkers is clinically useful • (Conde-Agudelo et al, BJOG, 2012)

31. Some test are not realistic to perform in general screening: -amniotic fluid ( by amniocentesis) ureplasma: +LR =10

32. Misty misty misty • Publications often mention OR and RR inappropiately • This gives a false impression of clinical relevance

34. The classics • History taking and risk scores • Clinical examination • Serum markers • Vaginal markers • Vaginal ultrasound

35. The classics • History taking and risk scores • Clinical examination • Serum markers • Vaginal markers • Vaginal ultrasound

36. The strongest predictor is a previous PTB • Not for this talk Honest, 2009

37. Risk identification is only helpful when combined with a program for modifying risk factors to improve outcome Anyoneusing a risk score To reduce risk?

40. Neither is there any evidence that specialised antenatal clinics reduce the number of preterm births • ( Whithworth, Cochrane, 2011)

41. Screening in women without previous PTB , singletons and without threatened preterm labour= asymptomatic

43. The classics • History taking and risk scores • Clinical examination • Serum markers • Vaginal markers • Vaginal ultrasound

44. BMI • Vaginal examination • (home uterine activity monitoring) • From face to face

45. BMI Khatibi et al AJOG 2012 • OR increases with obesity (prepregnancy BMI) < 32w : 3.24(1.71-6.14) <37w: 1.81 (1.29-2.54) 1 <32w:1.11(1.03-1.2) <37w:2.0(1.48-2.71)

46. Does lowering BMI lower the risk? • Is it part of the “general picture” • Fat womanwith rotten teeth, smoking likehell, using crack from time to time, havingsexwithnumerous partners , carrying chlamydia and havingrepeatedcystitis, living a sedentarylifewithlack of sunlight, vitamin D , havingno job, lowersocialclass

47. Home uterine activity monitoring • Does NOT predict preterm labour • Home uterine monitoring may result in fewer admissions to a neonatal intensive care unit but more unscheduled antenatal visits and tocolytic treatment. There is no impact on maternal and perinatal outcomes such as perinatal mortality or incidence of preterm birth. (Urquhart et al Cochrane, 2012)

48. Vaginal examination

49. Digital > 2 cm asymptomatic

50. Digital vaginal examination • Estimation of cervix is not unequivocal • Neither is nomenclature • Insufficient evidence to screen asymptomatic women with digital vaginal examination • (Reiter et al Acta Ob Gyn Sc, 2012)