Preterm Labor Flashcards
preterm birth
birth after 20wks; before 37 wks
late preterm
34-36wks
moderate preterm
32-33wks
very preterm
28-31wks
extremely preterm
<28wks
What are the 4 clinical processes of PTB?
1) premature activation of maternal or fetal hypothalamus pituitary adrenal (HPA) axis
2) pathological uterine distention
3) inflammation
4) decidual hemorrhage
What are risk factors for PTB?
- prior PTB = strongest risk factor!
- POVERTY!
- being black
- chronic stress
- low prepregnancy BMI (<19)/weight <50kg (2x risk)
- anxiety
weathering hypothesis
process of deteriorating health w/ cumulative disadvantage
What are PTB prevention methods?
- improved weight and nutrition
- reduce infection
- avoiding cocaine
- smoking cessation
- avoiding short (<18mo) interpregnancy interval
- dx and tx of asymptomatic bacteriuria
- improve sleep quality and reducing fatigue
ALSO:
- psychological counseling during pregnancy
- group prenatal care
- relaxation techniques (e.g. yoga)
What are non-successful prevention methods of PTB?
- home uterine monitoring
- bed rest
- prenatal tx of vaginal infections
What are nutritional interventions to reduce PTB risk?
- achieve appropriate prepregnancy weight
- gain adequate amt of weight for BMI
- take 200-300mg omega-3 fatty acids daily OR eat two fish meals/wk
- healthy, balanced diet
- achieve adequate iron stores
What is PTB prevention in high-risk pts?
- progesterone
- cerclage
What are guidelines for using progesterone?
- 250mg IM from 16-20wks through term in singleton pregnancy
- short cervix: suppositories before 33wks
- vaginal progesterone w/ no hx PTB and cervical length ≤20mm at 24wks or earlier
For which pts is cerclage indicated?
documented cervical insufficiency
When is cerclage typically performed?
before 24wks - controversial
Which pts should receive evaluation for cerclage?
1) hx cervical trauma (e.g. conization, LEEP)
2) progressively earlier births
3) two or more consecutive prior second trimester pregnancy losses
4) 3 or more early (<34wks) PTBs
How can PTL and PPROM be assessed/dx’ed?
1) fetal fibronectin testing (fFN)
2) cervical length measurement
* both together, increases predictive power of both*
3) clinical dx
Describe the presence of fetal fibronectin
- high concentrations in amniotic fluid and interface b/w decidua and trophoblasts
- normally found in cervical and vaginal secretions BEFORE 16-20wks GA
presence in cervicovaginal secretions AFTER 20 wks = abnormal EXCEPT as marker of imminent onset of labor at term
How is fFN testing performed?
- swab in posterior fornix of vagina
- rotate for 10sec
What can affect reliability of fFN testing?
w/in 24h - vaginal exam - sexual intercourse - endovaginal U/S - cervical exam OR - presents w/ vaginal bleeding
How is cervical length associated w/ PTB?
decreasing length, especially <25mm in 2nd tri = increased risk PTB
What sx of someone in PTL?
- menstrual-like cramps
- regular contractions
- low backache
- diarrhea
- sensation of pelvic pressure
What are clinical signs for dx of PTL?
Persistent uterine contractions: 4 q20mins OR 8 q60mins (or ≥6/hr*) WITH:
- documented cervical change OR
- cervical effacement of at least 80% OR
- cervical dilation ≥2cm
- rupture of membranes*
If do not meet these criteria = false labor
*from lecture
What is the time frame for management of PTL?
admit, discharge, or transport w/in 4h of evaluation
