Preterm Labor International Preterm Labor

International Objectives Definition and Incidence Etiology Diagnosis Management - Delaying delivery - Promoting fetal maturity - When to transfer - Delivery

Preterm Labor International Definition regular uterine contractions accompanied by progressive cervical dilatation and/or effacement at less than 37 weeks gestation  20 to 50% of PTL diagnosis is incorrect

Preterm Labor International Dilemma interventions to stop preterm labor are not particularly effective - especially when not instituted early 'Solution' diagnosis based on some degree of uterine activity combined with a single cervical exam suggesting early dilatation or effacement

Preterm Labor International Diagnosis establish dates history of contractions, risk factors abdominal exam for uterine activity cervical exam - serial if reasonable sterile speculum exam alone should be done in PPROM defer digital exam if there is undiagnosed vaginal bleeding until _______ of placenta is known

Preterm Labor International Establishing the EDD - LMP Naegele's Rule can be used in conjunction with the LMP if: -first day of last menses is known -period was 'normal' -cycle is regular and between 24 and 35 days -no recent hormonal contraception, lactation or pregnancy (3 subsequent spontaneous periods)

Preterm Labor International Establishing the EDD - When ultrasound is available Ultrasound should be used when the LMP is unknown or criteria are not fulfilled for its use in calculating the EDD U/S dating accuracy decreases as gestational age increases weeks GA  ± 5 days weeks GA  ± 1 week weeks GA  ± 2 weeks -> 30 weeks GA  ± 3 weeks

Preterm Labor International Establishing the EDD please tell someone the EDD! -inform woman of EDD from LMP if appropriate and reinforce at time of dating and/or 18 week ultrasound -document EDD on antenatal forms -document dates and findings of each ultrasound on antenatal (include placental location) good dating is useless if no one but you knows the EDD and you are not available

Preterm Labor International Incidence preterm delivery occurs in about 7% of pregnancies there has been little change in this rate despite new technologies

Preterm Labor International Significance preterm birth accounts for 75% of perinatal mortality significant longterm neonatal/pediatric sequelae -CNS and neurodevelopmental -respiratory -blindness and deafness

Preterm Labor International Etiology Idiopathic Antepartum haemorrhage Preterm prelabor rupture of membranes Chorioamnionitis Multiple pregnancy / Polyhydramnios Incompetent cervix / Uterine Anomaly Maternal disease Fetal anomaly

Preterm Labor International Management of Preterm Labor Four Objectives: 1.Early diagnosis of preterm labor 2.Identify and treat the underlying cause of preterm labor if possible 3.Attempt to stop labor when appropriate 4.Minimize neonatal morbidity and mortality

Preterm Labor International Management - Prolongation of Pregnancy  less than 40% of patients in preterm labor will be candidates for tocolysis Goal of Tocolytic Therapy Delay delivery when appropriate -gain 48 hours for corticosteroids -transport -optimize personnel

Preterm Labor International Management - Tocolysis Contraindicated contraindication to continuing pregnancy e.g. severe pregnancy induced hypertension, chonoamnionitis intra- uterine fetal death contraindication to specific tocolytic agents

Preterm Labor International Tocolytics - No strong evidence for efficacy Fluid bolus - small trial (n=48), no detected effect Ethanol -small trials, no benefit over placebo -ritodrine more effective in comparative trials -concerns re: adverse effects Sedation - no evidence, concern re: adverse effects

Preterm Labor International Tocolytics - No strong evidence for efficacy Magnesium sulfate -small, poor quality trials; placebo and comparative -no benefit shown

Preterm Labor International Tocolytics - Good evidence for efficacy  -sympathomimetics (ritodrine) -highly effective for delaying delivery in the short term -no demonstrated effect on neonatal outcome PG synthetase inhibitors (indomethacin) -more effective than placebo in delaying delivery >48 hours and beyond -no demonstrated positive effect on neonatal outcome -small trials, concern re: adverse effects Calcium channel blockers (e.g. nifedipine)

Preterm Labor International Side Effects of  -mimetics tachycardia - maternal and/or fetal headache and nasal congestion hyperglycemia / hypokalemia hypotension pulmonary edema -multiple gestation -other interventions -infection myocardial ischemia

Preterm Labor International Contraindications to  -mimetics Maternal cardiac disease - structural, ischemic, rhythm Significant antepartum haemorrhage Poorly controlled medical condition -type I diabetes mellitus -hyperthyroidism Contraindication to prolongation of pregnancy -preeclampsia or other medical indication -chorioamnionitis, suspected fetal compromise -mature fetus / imminent delivery / IUFD or anomaly

Preterm Labor International Minimizing Neonatal Adverse Outcomes Respiratory distress syndrome (RDS) is a major concern with preterm delivery Incidence of RDS has improved due to newer therapies RDS plays a role in several other conditions -intraventricular haemorrhage (IVH) -necrotising enterocolitis (NEC) -persistent pulmonary hypertension (PPHN) -other respiratory conditions

Preterm Labor International Meta-analysis of Antepartum Steroids 15 trials evaluating antenatal glucocorticoids for the reduction of RDS in preterm infants (>24 weeks and < 34 weeks) an incomplete course of steroids may still be beneficial P. Crowley CCPC Review No

Preterm Labor International Effect of Corticosteroids on Neonatal Outcomes RDS IVH NEC Perinatal Infection Neonatal Death Odds Ratio (95% Confidence Interval) P. Crowley CCPC Review No

Preterm Labor International Recommendations Which steroid ? betamethasone 12 mg IM q 24h x 2 doses (or q 12h) dexamethasone 6 mg IV q 12h x 4 doses (or q 6h) Beware steroids in the presence of infection steroids in combination with tocolytics in multiple gestation or diabetes

Preterm Labor International Recommendations When should steroid therapy be instituted? lower gestation limit weeks upper gestation limit weeks prophylactic administrationdepends on diagnosis and risk repeated administrationunknown

Preterm Labor International Recommendations Who is a candidate for antenatal steroid therapy? Considerations preterm labourYES cause preterm PROMYES infection hypertensivesYES urgency diabeticsYES type, sugars IUGRYES urgency multiple gestationYESpulmonary edema

Preterm Labor International Decision to Transport Available level of neonatal or obstetrical care Available transport and skilled personnel Travel time Risk of journey - maternal and fetal/neonatal well-being Risk of delivery en route -Parity, length of previous labour -State of cervix -Contractions -Response to tocolytics

Preterm Labor International Transport Plan Copies of antenatal forms, lab results, ultrasounds Communication -with patient and family -with receiving physician re: indication, stabilization, optimization, mode of transport, E.T.A. Appropriate attendant IV access, indicated medications, appropriate equipment Assess patient immediately prior to transport

Preterm Labor International Preterm Delivery caesarean not indicated on basis of prematurity recommendation for C/S of breech < 31 weeks not based on good evidence prophylactic outlet forceps not indicated routine episiotomy not indicated personnel skilled in neonatal resuscitation present

Preterm Labor International Conclusion Prompt and accurate diagnosis Identify and treat underlying cause if possible Attempt to prolong pregnancy if appropriate Intervene to minimize neonatal mortality and morbidity -antenatal steroid therapy -maternal transport -optimize local resources if unable to transport

Preterm Labor International Prelabor Rupture of the Membranes (PROM)

Preterm Labor International Objectives Definition Diagnosis Management - Preterm and Term

Preterm Labor International Definition rupture of the membranes before the onset of labor – preterm- < 37 weeks gestation (PPROM) – term -  37 weeks gestation (TPROM)

Preterm Labor International Latent Period time from rupture until onset of labor earlier the gestation the longer the latent period At term - 90% go into labor within 24 hours At weeks – 50% go into labor within 24 hours – % go into labor within 1 week

Preterm Labor International Etiology of PROM idiopathic infection (e.g. bacterial vaginosis) polyhydramnios cervical incompetence uterine abnormality following cervical cerclage or amniocentesis trauma

Preterm Labor International Diagnosis of PROM history sterile speculum exam ( avoid digital exam) – glistening, washed out vagina – fluid pooling in posterior fornix – free flow from cervix – pH testing of fluid (nitrazine paper) - non specific – ferning ultrasound - PROM less likely if normal fluid volume

Preterm Labor International Complications of PROM - Term fetal / neonatal infection maternal infection umbilical cord compression / prolapse failed induction resulting in cesarean section

Preterm Labor International Complications of PROM - Preterm preterm labor and delivery fetal / neonatal infection maternal infection umbilical cord compression / prolapse failed induction resulting in cesarean section pulmonary hypoplasia (early, severe oligohydramnios) fetal deformation

Preterm Labor International Management - General assess maternal and fetal well-being confirm diagnosis assess cervical status by speculum exam (sterile) avoid digital cervical exam assess for conditions requiring concurrent management e.g. presence of temperature or maternal or fetal tachycardia assess for indications for immediate delivery

Preterm Labor International Management - Term (> 37 weeks) avoid digital cervical exam assess for infection consider need for antibiotics if prolonged PROM expectant or active management depending on circumstances and patient preference

Preterm Labor International Management - Preterm (34-37 weeks) avoid digital cervical exam consider antenatal steroids intrapartum antibiotic prophylaxis surveillance for infection - clinical (monitor maternal temperature and pulse, fetal heart rate) appropriate antibiotics for chorioamnionitis if develops

Preterm Labor International Management - Preterm (< 34weeks) avoid digital cervical exam steroids antepartum and intrapartum antibiotics to mother surveillance for infection - clinical (monitor maternal pulse and temperature, fetal heart rate, presence of uterine irritability) appropriate antibiotics for chorioamnionitis if develops consider transfer to higher level of care center if appropriate expectant management (possibly outpatient)

Preterm Labor International Antibiotic options are : Women with suspected chorioamnitonitis require broader range spectrum antibiotic coverage Iv Penicillin G 5 million units q 4-6h preferred or Ampiullin Iv Ampiullin 2g followed by 1 g q 4h or Clindamyin IV Clindamyin 600 ng q 8h