Table of contents
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
1. Contractions?
2. Bleeding?
3. Rupture of Membranes (ROM)
4. Baby movement
- 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
- 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.
- Contractions: of sufficient frequency and intensity.
- Swab for fetal fibronectin (FFN)
- 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.
- 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)
- Magensium sulphate (reversible with calcium gluconate)
- 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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