Labour

    Definitions

    Labour - Progressive cervical dilation or effacement
    False Labour - Regular uterine contractions with no dilation/effacement of cervix

    Labour Diagnosis

    Ruptured Membranes

    • Nitrazine Test - turns dark blue when wet with amniotic fluid (also positive for blood, semen, vaginitis, so  not diagnostic of amniotic fluid presence)
    • Fern Test - smear fluid on slide, let dry, and check under microscope for fern-like pattern

    When to go to hospital

    • When Spontaneous rupture (SROM)
      • if green - go to hospital (meconium - fetal distress)
      • if bloody - go to hospital
      • if GBS+ - go to hospital (abx)
      • if baby not in vertex position
    • If all is good, call L&D, labour will start in 24hrs.

    Fetal Position

    Presentation
        Body part closest to the birth canal
        - Cephalic (vertex)
        - Breech (Frank, complete, footling)
        


        - Tranverse (Shoulder)
        - Compound

    Lie
        - Longitudinal
        - Transverse
        - Oblique

    Position
        - Occiput for vertex presentations
        - Sacrum for breech
        - Mentum for face (chin)
        - (Most common LOA)



    Station
        - In relation to ischial spines
        - Above: -5-1
        - Engagement: 0
        - Below: +1 - +5

    Stages of Labour

    Stage 1:

    • Latent Phase - irregular uterine activity of varying intensity, no progressive cervical changes
    • Active Phase - strong regular uterine contractions, w/ progressive/redictable cervical changes

    Stage 2:

    • Full dilation up to and including delivery of infant

    Stage 3:

    • Delivery of infant to delivery of placenta

    Stage 4:

    • One our following delivery

    Premature Labour


    -  How to extend labour (by ~48hrs to give time for steriods to develop lungs):
    Tocolytic Medications:

    • Magnesium Sulfate (safe, but watch for toxicity: resp depression, loss of deep tendon reflexes, cardiac).  Give 1g CaGluconate if needed.
    • Indomethacin - Prostaglandin inhibitor (NSAID) -  Works by decreasing inflammation. Use if <30 weeks (over 30 wks not enough inflammation to work well unless polyhydramnios), also can close ductus arteriosis if >32 weeks.
    • Nifedipine - very effective, may be more effective than others.  Less NICU admits, protects against RDS, necrotizing enterocolitis, and intraventricular hemorrhage.
    • Atosiban - Oxytosin blocker
    • B2-agonists (Terbutaline, Salbutamol)

    -  Steroids to develop lungs (Give in 24-34weeks) Idealy 12h of steroids for max effect (initiates surfactant production)

    • Betamethasone (Celexone) 12mg q24 x2doses
    • Dexamethasone 6mg q6h x4doses

    Pre-term Labour

    -  4 Questions to ask in labour
            1. Contractions?
            2. Bleeding?
            3. Rupture of Membranes (ROM)
            4. Baby movement
    Risk Factors
    • Cervical Trauma (previous treatment for cervical cancer etc.. risk of preterm directly proportional to amount of tissue removed)
    • Gental tract infection (Bacterial vaginitis linked to 40% increase in preterm delivery, but antibiotics do not help (thought treat the infection)
    • Previous preterm labour/birth (baseline 10-12%.  risk of 1, 2, 3rd: 15%, 30%, and 45% respectively). 
    • Midtrimester Loss
    Cervical Length Assessment at 24-28 weeks is the most sensitive predictor of preterm birth, but controversial.
    Other Fun Facts:
    • Progesterone therapy: has been shown helpful to prevent pre-term birth if cervical length <15mm.  Not recommended for use in women with multiple gestations (no help).
    • FDA approved 17-hydroxyprogesterone (Makena) to reduced risk of preterm delivery <37w.
    Diagnosis
    • Contractions: of sufficient frequency and intensity.
    • Swab for fetal fibronectin (FFN)
    Fetal Fibronectin
    • Vaginal swab.
    • Must have nothing in vagina in the past 24 hours (no intercourse, blood, or pelvic examinations)
    • FFN is a protein that glues the gestational sac to the uterus, and usually leaks into the vagina before labour.
    • Can repeat weekly. 
    • If Positive: Inconclusive, cannot rule out labour.
    • If Negative: 95% chance that the woman won't go into labour in the next 7-10 days.
    Treatment/Tocolytics
    • Indications: >6 contractions/hour + cervical change).... If no cervical change: use therapeutic sleep with morphine sulphate 10-15mg sc.
    • Give tocolytics to delay delivery for 48hrs to allow action of glucocorticoids to decrease incidence of RDS (resp distress syndrome).
    • Bed rest is pretty good too (some argue the same efficacy)
    • Types:
      • Magensium sulphate (reversible with calcium gluconate)
        • Also neuroprotects - reduces cerebral palsy if used 24-31+6w.
        • 4g IV loading over 30min, then 1g/hr maintenance until birth.
      • Nifedipine
        • Blocks smooth muscle contraction (blocks calcium)
        • May be more effective than the others, lower admissions to NICU, lower incidence of RDS, and necrotizing enterocolitis, and intraventricular hemorrhage.
      • Indomethacin
        • Works better if <30 weeks (more significant inflammatory response then)
        • Can decrease fetal renal blood flow if used >48hrs. monitor AFI (amnionic fluid index).
        • Premature closure of ductus arteriosis if used >32 weeks.
        • Not recommended >32 weeks.
      • Transdermal nitrates
      • Atosiban - Oxytosin blocker
      • B2-agonists (Terbutaline, Salbutamol)
    Steroids to Mature Lungs
    • Need at least 12 hours to have max benefit.
      • Betamethasone 12mg q24hrs x2 doses
      • Dexamethasone 6mg q6h x4 doses

    Fetus

    • Normal Fetal Weight:
      • 5.5lb-10lb
      • 2500 - 4500g

    GBS

    • -  Swab Done at 28-30wks and 36wks (Recto-vaginal)
    • -  GBS - Strep. agalactiae
    • -  Many women carriers, status can change (10-30%)
    • -  If negative within 5 weeks of delivery, no antibiotics
    • -  Give antibiotics (Ancef) or Penicillin G to prevent neonatal GBS infection
    • Neonatal GBS infection:
      • Strep. agalactiae - normally in gut flora, only infects immunocompromised people, can give mastitis in cows causing no milk (hence called "agalactiae" meaning "no milk").
      • Early septicimia: 0-7days: often accompanied by pneumonia (if aspirated during birth)
      • Late septicimia: 7-90 days: often accompanied by meningitis
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