Preterm Birth Hazem Al-Mandeel, M.D Course 481 Obstetrics and Gynecology Rotation

Definition and Incidence Preterm birth is the delivery of a fetus after 20 wks of gestation and before term (completed 37wks) Preterm Labor is ……………… Preterm birth is a major cause of perinatal mortality and morbidity PTB occurs in 10% to 12% of pregnancies 50% to 70% of neonatal mortality and morbidity is secondary to PTB

Etiology and Risk Factors 3 etiologic subtypes of PTB: 1.Spontaneous PTB (idiopathic) 2.Preterm premature (prelabor) rupture of membranes 3.Induction of Labor for medical indications Risk Factors: H/O preterm birthMultiple gestation PolyhydramniosUrinary tract Infection Abortion (especially 2 nd trimester) Cervical incompetence Ethnic background

Diagnosis of Preterm Birth Diagnosis done by clinical assessment Initial assessment of women with preterm labor and intact membrane is by pelvic examination Dx of PTB is based on: 1.Documented uterine contractions 2.Documented cervical dilatation or change

Management of Preterm Labor Complete assessment of the patient for possible corrected underlying cause (e.g. UTI) Rule out the presence of premature rupture of membranes Start I.V hydration and bed rest Obtain vaginal swab and urine for culture (R/O vaginal infection or UTI) Obtain obstetrical ultrasound to assess fetal presentation, weight, and cervical length

Management of Preterm Labor If gestational age is ≥ 34wks  no further action If gestational age is < 34wks  consider the following: 1.Antenatal corticosteroid (glucocorticoids) to reduce risk of preterm mortality and morbidity 2.Uterine tocolytic therapy (to stop or delay delivery) e.g.: Ritodrine, Nifedipine, NSAID, Oxytocin antagonists C.I: antepartum bleeding, severe preecalmpsia, chorioamnionitis, IUGR, IUFD, fetal anomalies 3.Antibiotic therapy (for Group B streptococcal prophylaxis)

Labor and Delivery of the Preterm The Lower limit of viability of a preterm infant is 24 wks or 500g weight Vaginal delivery is preferred in vertex presentation If breech presentation cesarean section is preferable Continuous fetal heart monitoring is necessary Vacuum/ventose assisted delivery should be avoided Neonatal intensive care unit is

Prevention 1. Identify patients at risk and provide close follow up 2. Treatment of bacterial vaginosis 3. Treatment of asymptomatic bacturia 4. Measurement of cervical length in high risk patients 5. The use of fetal fibronectin test for women with PTL 6. Stress reduction and improvement of nutrition