PRETERM LABOUR

1. PRETERM LABOUR

2. Learning objectives • Definition • Etiology • Risk factors • Diagnosis • Preventive modalities • Plan appropriate treatment modalities • Tocolysis –indication ,C/I , drugs • Principles of intrapartum management • Neonatal care, complications

3. Definition • PTL is defined as one where labour starts after the gestation of viability (20 -28 wks) and before the 37th completed wks from the first day of LMP (259days).

4. Preterm is defined as the occurrence of regular uterine contractions (4 or more in 20 minutes or eight or more in one hour) and • Cx changes (effacement equal to or more than 80% and dilatation equal or greater than 2cm) in women with intact fetal membranes and gestational age <37 weeks.

5. Incidence : 10-15% PTL – significant cause of PN morbidity & motality • Very early <32 wks • Early preterm labour 32-34 wks • Late preterm labour 34-37 wks

6. Etiology - Maternal factors • Extremes of age • Under nutrition • Poor maternal weight gain • Low SE status • Ethnic differences • Smoking • preg. following ART • Physical / psychological stress • Lack of antenatal care

7. Etiology -Pregnancy complication • Pre-existing maternal illness • Acute systemic infection in mother, • Preeclampsia, PPROM, APH • Genital infections – BV, beta hemolytic strep • Polyhydramnios, MP, IUFD • Fetal malformation • Asymptomatic bacteriuria /recurrent UTI

8. Etiology - Obstetric history • Previous preterm birth • Previous first / second trimester loss • Previous induced abortion

9. Etiology -Uterine factors • Cx insufficiency • Bicornuate uterus • H/o diethyl stilbesterol, submucus fibroid • Iatrogenic • idiopathic

10. Types of PTL : • Spontaneous PTL • Iatrogenic PTL • Preterm premature rupture of membranes • Threatened PTL • Advanced PTL

11. Prediction of PTL • Prior preterm birth – three fold increase • Screening for bacterial vaginosis • Ultra sound cx assessment : cx length <25mm at 24 wks of gestation • Fetal fibronectin : > 50 ng/ml • Maternal salivary estriol /plasma corticotropin releasing hormone • Ambulatory uterine activity monitoring

12. Etiopathogenesis of PTL • 80% of Preterm births are spontaneous • 50% Preterm labor • 30% Preterm premature rupture of the membranes • Pathogenic processes • Activation of the maternal or fetal hypothalamic pituitary axis • Infection • Decidual hemorrhage • Pathologic uterine distention

13. Activation of the HPA Axis • Premature activation • Major maternal physical/psychologic stress • Stress of uteroplacental vasculopathy • Mechanism • Increased Corticotropin-releasing hormone • Fetal ACTH • Estrogens (incr myometrial gap junctions)

14. Inflammation • Clinical/subclinical chorioamnionitis • Up to 50% of preterm birth < 30 wks GA • Proinflammatory mediators • maternal/fetal inflammatory response • Activated neutrophils/macrophages • TNF alpha, interleukins (6) • Bacteria • Degradation of fetal membranes • Prostaglandin synthesis

15. Diagnosis • Regular uterine contractions 4/or > in 20mins. • Eight or > in 60min each should last for 40 seconds • Pelvic pain, low backache • Dilatation • effacement

16. Management • Prevent • Arrest of PTL • Management of advanced PTL • Care of new born

17. Prevention • Primary -General measures : improve general health, nutrition, infection • Good antenatal care • Early detection of obstetric compl. • Secondary –screening test, prophylactic treatment • Tertiary care –reduce the PN mobidity & mortality

18. Progesterone : • 17 hydroxy progesterone caproate given weekly injections – 16-36 weeks. Vaginal progesterone Cerclage : • Cervical insufficiency • USG indicated • Rescue cerclage • Screening for BV in women with previous preterm labour

19. investigations • History / clinical examination • CBC, CRP, HVS • Urine c/s • USG – fetus / Cx. length

20. Bed rest, hydration Antenatal steroids : • Between 24-34 weeks gestation • Betamethasone12 mg 2 dose 24 hr apart • dexamethasone 6mg 4 doses 12 hr apart • Risk of antenatal steroid.

21. Tocolysis : • Main use is to gain time for steroids to act, • delay delivery for at least 48 hrs. • for in utero transfer to tertiary centre

22. C/I to tocolysis • IUFD, • fetal anomaly • chorioamnionitis • Maternal /fetal condition requiring immediate delivery.

23. Commonly used tocolytics • Betamimetics • Magnesium sulfate • PGSI –Premature closure of DA/oligohydraminos neontal pul. HTN • Nitric oxide donor • Oxytocin antagonists • Calcium channel blockers

24. Active management Delivery : • Tertiary centre • CS for preterm breech (lower segment vertical/J shaped) • Cx antibiotics – group B streptococcus • Patient in lateral position Avoid ambulation • Ensure adequate fetal oxygenation • CEFM

25. Avoid narcotics – epidural is preferred • Episiotomy • Outlet forceps • Cord to be clamped at birth • To shift the baby to NICU under neonatologist

26. Complications of new born -early • Apnea, • birth asphyxia • RDS • feeding problems, • aspiration • Pul hge • IVH • hypoxic ischemic encephalopathy • Hyperbilirubinemia • NEC • Acidisis • electrolyte imbalance • Infection • birth injuries • Haemorrhagic disease of new born

27. Late complications • Cerebral palsy • seizures • Retinopathy ofprematurity • Anemia, • mental retardation • Bronchpulmonary dysplasia • PDA, • hearing loss • Malabsorption syn • Nephrocalcinosis, • rickcets • Learning disabilities • Sudden infant death syndrome