Abnormalities of Pregnancy 2

Question 1

What is the definition of preterm birth? And how common is it?

Answer 1

• Preterm birth = delivery prior to 37 weeks gestation
• Incidence of PTB in U.S. approximately 12%
• Accounts for 85% of perinatal morbidity and mortality
• Neonatal outcome primarily dependent upon gestational age
• Etiologies
  
  • Spontaneous preterm delivery
  • Iatrogenic

Question 2

What is the definition of preterm labor? What are some possible contributing factors?

Answer 2

• Definition: Uterine contractions associated with cervical dilation
• Possible contributing mechanisms
  
  • Infection/inflammation
  • Excessive uterine stretch (multiple gestation, polyhydramnios)

Question 3

What are some common risk factors for preterm labor?

Answer 3

• Intraamniotic infection
• Multiple gestation
• Placental abruption
• Prior preterm delivery
• 2nd or 3rd trimester bleeding
• Uterine anomalies
• Pyelonephritis
• Smoking
• Illicit drug use
• African-American race
• Low SES

Question 4

What are the goals of diagnosis for preterm labor?

Answer 4

• Transfer to facility with appropriate NICU
• Administration of antenatal corticosteroids
• Treat with antibiotics effective against GBS
• Diagnose and treat underlying causes

Question 5

What are treatment options for preterm labor?

Answer 5

• Tocolytics x 48 hours
• Contraindications: Intraamniotic infection, significant maternal bleeding

Question 6

What are some methods of prevention for preterm birth?

Answer 6

• 17-hydroxyprogesterone caproate
• Vaginal progesterone
• Cerclage in short cervix (if prior PTB)
• Screen/treat asymptomatic bacteriuria
• Treat symptomatic bacterial vaginosis
• Smoking cessation
• > 18 month interpregnancy interval

Question 7

What is the definition of cervical insufficiency? What are some possible mechanisms?

Answer 7

• Definition: Painless cervical dilatation in the absence of contractions usually occurring in the mid-trimester
• May result in prolapsed membranes or PPROM and resultant PTD
• Possible contributing mechanisms
  
  • Remains unknown

Question 8

What are some risk factors for cervical insufficiency?

Answer 8

• Prior pregnancy with cervical insufficiency
• Possibly multiple gestation

Question 9

What are contradindications for using cerclage in cervical insufficiency?

Answer 9

• Contractions/labor
• PPROM
• Vaginal bleeding
• Infection
• Fetal demise or major fetal anomaly

Question 10

What is the definition of preterm premature rupture of membranes? What are some possible contributing mechanisms?

Answer 10

• Definitions
  
  • PROM (premature rupture of membranes): Rupture of membranes prior to the onset of labor
  • PPROM (preterm premature rupture of membranes): Rupture of membranes prior to the onset of labor and before 37 weeks gestation
• Possible contributing mechanisms
  
  • Alteration in cervical stromal composition
  • Induction of amniotic membrane matrix metalloproteinases

Question 11

What is the diagnostic process for preterm premature rupture of membranes?

Answer 11

• Sterile speculum exam
  
  • Vaginal pooling
  • Basic pH of fluid
  • Microscopic “ferning” pattern

Question 12

What are the common outcomes for PPROM?

Answer 12

• Interval between PPROM and delivery dependent upon gestational age
  
  • 2/3rds will deliver within 7 days
  • 50% of these women will deliver within 24-48 hours

Question 13

What is the management of PPROM?

Answer 13

• Confirm gestational age
• If < 34 weeks gestation, expectant management with administration of steroids and antibiotics for latency
• Hospitalize for duration of pregnancy
• Initiate fetal surveillance
• Delivery at 34 weeks