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Preterm Birth. Present by: Dr.Worapa Asavaritikrai Health Promotion Center Region 4. Objective. Definition Risk factors Diagnosis Treatment. Definition of Preterm Birth. A birth that occurs before 37 completed w ee ks of gestation (<259 days)
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Preterm Birth Present by: Dr.Worapa Asavaritikrai Health Promotion Center Region 4
Objective • Definition • Risk factors • Diagnosis • Treatment
Definition of Preterm Birth • A birth that occurs before 37 completed weeks of gestation (<259 days) • Late preterm births, defined as 34-36+6 weeks of gestation (~ 75% of all preterm birth)
SURVIVAL RATE OF INFANTS RAMATHIBODI HOSPITAL (2000-2008)
Reasons for preterm delivery • 4 main direct reasons: • Maternal or fetal indications • Spontaneous unexplained preterm labor with intact membranes • Idiopathic preterm premature rupture of membranes (PPROM) • Twins Cunningham et al, 23rd Ed Williams Obstetrics
Definition of PPROM • Defined as rupture of the membranes before labor and prior to 37 weeks of gestation
Antecedents & Contributing Factors • Threatened Abortion • Lifestyle Factors • Racial & Ethnic Disparity • Work During Pregnancy • Genetic Factors • Periodontal Disease
Antecedents & Contributing Factors • Birth Defects • Interval between Pregnancies & Preterm Birth • Prior Preterm Birth • Infection • Bacterial Vaginosis
Prevention of preterm birth ร่างแผนการดูแลการเจ็บครรภ์คลอดก่อนกำหนดClinical Practice Guidelinen of Preterm labor
Preventions of PretermBirth • Primary Prevention • Secondary Prevention • Tertiary Prevention
Preconceptional • Public educational interventions: • Increased awareness • Uterine curettage or endometrial biopsy • Reduce prevalence of smoking • Reduce risk of higher-order multiple gestation • Socioeconomic approach
During Pregnancy • Smoking cessation in pregnancy • Prenatal care • Periodontal care ?? • Screening of low-risk women
Smoking cessation A Cochrane review reported that smoking cessation programmes in pregnancy successfully reduce the incidence of preterm birth (RR 0·84, CI 0·72–0·98) Lumley J.Cochrane Database Syst Rev 2004
Prenatal Care High rate of preterm birth in women who receive no prenatal care than from the content of care for those who receive it
Periodontal care Treatment during pregnency improved periodontal disease and it is safe, but it did not significantly alter rate of preterm birth Michalowicz BS. N Engl J Med 2006; 355: 1885–94
Screening of low-risk women -Screening and treatment of asymptomatic bacteriuria prevent pyelonephritis -Given antibiotic in low-risk does not reduce this risk of preterm birth Cunningham et al, 23rd Ed Williams Obstetrics
Fetal fibronectin testing • Glycoprotein • Marker of choriodecidual disruption • Levels > 50 ng/mL ( >22 weeks) associated with an increased risk of spontaneous preterm birth The Cochrane Library 2009, Issue 2
Cervical length • Cervical shortening is a risk factor for preterm delivery • Especially useful in asymptomatic women : at 24 wks, a cervical length < 25 mm
Tertiary Prevention • Early diagnosis of preterm labour • Treatment of women with acute risk of preterm birth • to arrest preterm labour : tocolysis • antenatal corticosteroid use • antibiotic for group B streptococcal prophylaxis
Diagnosis of pretermlabor • Regular contractions accompanied by cervical change at less than 37 weeks • ACOG 1997 criteria preterm labor: • Contractions of four in 20 min. or eight in 60 min. + progressive change in the cervix • Cervical dilatation > 1 cm • Effacement > 80%.
Threatenedpretermlabor Regular contractions without cervical change
Management of Preterm Labor • PPROM • Preterm labor with intact membranes
Tocolytic agents • ACOG 2007 has concluded that tocolytic agents do not markedly prolong gestation, but may delay delivery in some women for at least 48 hours
Tocolytic agents • Β-Adrenergic receptor agonists • Ritodrine, Terbutaline • Magnesium sulfate • Prostaglandin inhibitors • Calcium-channel blockers • Atosiban • Nitric oxide donors
Terbutaline Hearne AE, Nagey DA. Therapeutic agents in preterm labor: tocolytic agents. Clin Obstet Gynecol 2000;43:787-801
Magnesium sulfate Hearne AE, Nagey DA. Therapeutic agents in preterm labor: tocolytic agents. Clin Obstet Gynecol 2000;43:787-801
Nifedipine Hearne AE, Nagey DA. Therapeutic agents in preterm labor: tocolytic agents. Clin Obstet Gynecol 2000;43:787-801
Corticosteroid Therapy • Enhance fetal lung maturation • Rescue therapy? • Betamethasone is superior to Dexamethasone • Regimens: • Two doses of Betamethasone 12 mg IM q 24 hrs • Four doses of Dexamethasone 6 mg IM q 12 hrs
Group B streptococcus prophylaxis • Goal is neonatal sepsis prevention • Not to prevent preterm birth
Group B streptococcus prophylaxis Centers for Disease Control and Prevention, 2002d
Recommended Management of Preterm Labor • Confirmation of preterm labor • GA <34 weeks: corticosteroids are given for enhancement of fetal lung maturation • GA <34 weeks: reasonable to attempt inhibition of contractions to delay delivery while given corticosteroid & group B streptococcal prophylaxis • GA >34 weeks: monitor for labor progression & fetal well-being