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
- 4 Questions to ask in labour
1. Contractions?
2. Bleeding?
3. Rupture of Membranes (ROM)
4. Baby movement
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)
- Magensium sulphate (reversible with calcium gluconate)
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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