PRE-TERM LABOR

1. PRE-TERM LABOR Insert Presenter’s Name Dr Uma.T Department of Obstetrics and Gynecology SAT Hospital,Government Medical College Trivandrum

2. PRETERM LABOUR Def : Regular painful uterine contractions after 20 wks and before 37 wks Associated with effacement and dilatation of cervix Incidence – 20 – 30% Impact – Regarding chance of survival of preterm neonate - Quality of life achieved.

3. AETIOLOGY Maternal Characteristics • Age – Low & High • Socioeconomic status– Poor • Physical Activity • Maternal habits & – Cigarette, addictions Alcohol, Cocaine • Psychological Stress

4. MATERNAL SYSTEMIC DISEASES • Renal Diseases – Acute infection & asymptomatic bacteruria • Hypertensive disorders • Maternal diabetes – Hydramnios • Immunological disorder – SLE, APLA syndrome

5. MATERNAL INFECTIONS • Febrile illnesses – Malaria • Infective diseases – Syphilis, toxoplasmosis • Chorioamnionitis • Bacterial vaginosis - PPROM

6. UTERINE FACTORS • Uterine Malformations • Cervical incompetence • Previous history of abortion & Preterm births PREGNANCY COMPLICATIONS • Multiple pregnancy • Hydramnios • Placenta Praevia or abruption GENETIC FACTORS

7. PATHOGENESIS • Exact mechansim not known • Fetus plays synergestic role • ↑ PG synthesis – stimulated by intrauterine infection, haemorrhage, overdistension etc. • From decidua & fetal membranes • ↑ Cytokines, IL – 6, IL - 1, TNF, PAF – produced by fetal lungs, kidney

8. PREDICTION OF PRETERM LABOUR • Measuring cervical length using TVS – • At 24 wks – Mean cervical length is 35 mm . • Shortened cervix had ↑ rate of preterm labour • Requires special expertise • History of preterm birth • Fetal fibronectin – in cervicovaginal secretions • Ambulatory uterine contraction testing • Maternal Salivary estriol – not used

9. DIAGNOSIS • Contractions at a frequency of 4 in 20 mts. or 8 in 60 mts. • Cervical dilatation more than 1 cm. • Cervical effacement of 80% or greater.

10. MANAGEMENT Depends on gestational age and neonatal care facilities • Gestational age between 24 and 34 wks – administer corticosteroids • 2 doses of 12 mg betamethasone given intramuscularly 24 hour apart. • If delivery occurs 24 hrs after completion of betamethasone and within 7 days, chance of respiratory distress less.

11. MECHANISM OF ACTION • Induces proteins that regulate biochemical systems in type 2 cells. • Increases alveolar surfactant, compliance and lung volume. Adverse effects – Short term • Maternal – Pulmonary edema, infections, poor diabetic control • Fetal – Nil.

12. Epithelial cell Structural Development Steroids Type IIPneumocytes Apoproteins surfactant

13. Repeated Doses of Steroids? • Not recommended Adverse effects • Chorioamnionitis. • Cause early onset neonatal sepsis. • NND. • Low birth weight. • Abnormal psychomotor development.

14. Tocolysis in preterm labour • Does tocolysis prevent preterm labour? • No clear evidence improve outcome; only to complete course of corticosteroids or inuterotransfer (Evidence A) • Does tocolysis prevent NND and morbidity ? • No clear reduction (Evidence A)

15. INDICATION FOR TOCOLYSIS • Gestational age less than 37 wks • Cervical dilatation less than 3 cm • No history of unclean examination or evidence of chorio amnionitis. • No pregnancy complication like APH, PE • Fetus normal, alive, no signs of distress.

16. COMMONLY USED…

18. TOCOLYTICS Betadrenergic drugs Isoxuprine, Riltodrine, salbutamol, terbutaline • Inhibit uterine contraction by stimulating myometrial β-2 receptors. • Adverse effects due to stimulation of receptors elsewhere. • Maternal hypotension, Tachycardia, palpitation, fetal Tachycardia.

19. MAGNESIUM SULPHATE • High concentration decreases contractility • Not used for this purpose. PROSTAGLANDIN INHIBITORS • Aspirin, Indomethacin • Use avoided – Premature closure of neonatal ductusarteriosus and neonatal pulmonary hypertension

20. CALCIUM CHANNEL BLOCKERS • All smooth muscle activity related to free calcium in cytoplasm • Reduction in Calcium inhibits uterine contraction. • Nifedipine – Efficacy not been adequately studied.

21. Pre-term Labor in Women with a Past History of PTL Am J Obstet Gynecol. 1998;178(5):1035–1040.

22. Oral Micronized Progesterone Improves Maternal and Fetal Outcomes in Women with a History of PTL • Oral micronized progesterone was associated with • Improved birth weight (2400 g vs. 1890 g, p<0.001) • Lower stay in the neonatal ICU (p<0.001) • More favorable Apgar scores (p<0.001) 22 J Obstet Gynaecol. 2009;29(6):493–498. Int J Gynaecol Obstet. 2009;104(1):40–43.

23. Pre-term Labor and Uterine Abnormalities • Women with uterine anomalies have poorer reproductive outcomes when compared to that of the general population. • Unicornuate uterus is associated with the poorest fetal survival. • The incidence of preterm deliveries among women with bicornuate uterus and didelphic uterus has been reported in as high as one-fourth of the pregnancies J Womens Health (Larchmt). 2004;13(1):33–39.

24. Vaginal Micronized Progesterone for Prophylaxis of PTL – Results from Cetingoz et al. Vaginal progesterone (100 mg) administered between 24 and 34 weeks has the following outcomes in women with prior pre-term birth, twin pregnancy and uterine malformations Arch Gynecol Obstet 2011;283:423–429.

25. Pre-term Labor and Cervical Length – Results from Iams et al. • Even a small decrease in cervical length between the 24th and 28th weeks of gestation was associated with an increased risk of preterm birth (relative risk, 2.03; 95% CI, 1.28–3.22) N Engl J Med. 1996;334(9):567–572.

26. Progesterone Preserves Cervical Length – Results from O’Brien et al. Intravaginal progesterone preserves cervical length Ultrasound Obstet Gynecol 2009;34:653–659.

27. NEONATAL CARE • Preterm infants require neonatal intensive care. • If facilities not available, give corticosteroids and refer patient to appropriate higher centre INTRAPARTUM MANAGEMENT • Proper fetal heart rate monitoring • Delivery – RMLE put • If poor voluntary efforts in second stage – Outlet forceps.