1. Infection & Preterm Birth

2. Objectives Understand magnitude of problem of PTB.
Gain understanding of role of infection in spontaneous PTB.
Overview of clinical decision making and “art” of medicine regarding PTB.

3. Rate of PTB ~ 10% and increasing
Primary cause of neonatal morbidity and mortality
Pregnancy is usually seen as a time of exciting anticipation with the expectation that after 9 months the woman will give birth to a healthy beautify baby. Unfortunately, that is not always the case. About 10% of pregnancies are delivered before completing 37 weeks of gestation. Preterm birth, defined as delivery before completion of the 37th week of gestation, is the number one cause of neonatal morbidity and mortality.

5. Economic Impact of PTB
Hospital costs for preterm infants. Does not include cost of ongoing care of a disabled child

6. Risk Factors for Preterm Delivery
Previous obstetric history
Race/ethnicity
Multiple gestation
Incompetent cervix
Congenital Anomalies

7. Risk Factors for Preterm Delivery
Substance abuse
Pre-Pregnancy Weight
Stress
Maternal Age
INFECTION

8. Infection and PTB 40% of PTB due to infection
↓ Gestational Age Infection
Only pathologic process with firm causal link established
Fetal infection & inflammation  Cerebral palsy & chronic lung disease
IUI and Inflammation are frequently associated with PTL and delivery and at least 40% of all PTB are estimated to occur with mothers who have an IUI which is largely subclinical. The lower the GA at delivery, the greater the frequency of IUI.

9. Infection & PTB: Pathophysiology
Invasion of Amniotic Fluid
Fetal Invasion
Localized Inflammatory
Reaction
Stages of ascending IUI
Change in vaginal and cervical microbial flora or presence of pathologic organisms in the cervix
2. Microorganism spreads up to the chorion and amnion to reside in decidua and a localized inflammatory reaction
Change in flora

10. Case Study 1 24 yo at 23 weeks EGA with gush of fluid
Bacterial vaginosis diagnosed on vaginal exam
Admitted, antibiotics started, counseled
Family opts for expectant management
Counseling – options – then she develops fever and abdomenal tenderness
Next pregnancy

11. Case Study 1 Develops fever and uterine tenderness
Contractions increased
Vaginal delivery of 800 gm baby boy
Severe respiratory distress, multi-organ system failure.

12. Case Study 2
34 yo at 35 weeks with contractions and cervical dilation.
Group B Strep isolated from vagina at last prenatal visit.
Management options

13. Case Study 2 Amniocentesis showed mature fetal lungs
Antibiotics continued
Vaginal delivery
Baby weighted 5#5oz; stayed in nursery for 5 days then discharged to home. No long term sequelae.

14. Case Study 3
30 yo at 26 weeks presenting with flu-like illness, rash, vaginal discharge and uterine cramping.
Management options – keep mother from getting too ill with IV antivirals.
Primary Genital Herpes

15. Case Study 3 Intravenous anti-viral medication
Tocolytics to relax uterus
Contractions continued and membranes ruptured
Cesarean delivery of 2.5# infant

16. Case Study 3
Support in NICU
IV antivirals
Spinal tap
Disseminated HSV