Preterm Labour (PTL):
*labour occurring between 20 and 37 weeks
-10% of prenancies
-Can be idiopathic
-documented change in cervix
PTL Risk Factors: maternal
-infection (recurrent pyelonephritis, untreated bacteriuria, chorioamnionitis
-genital infection (eg. BV)
-HTN
-DM
-chrnoic illness
-mechanical factors
-previous obs, gyne, and abdominal surgeries
-socio-enviro: nutrition, smoking, drugs, alcohol, stress
PTL Risk Factors: maternal-fetal
-PPROM
-polyhydramnios
-placenta previa or abruption
-placental insufficiency
PTL Risk Factors: fetal
-multiple gestation
-congenital abnormalities of fetus
-fetal hydrops
PTL Risk Factors: Uterine
-incompetent cervix
- excessive enlargement
-malformations (leiomyomas, septate)
Prediction of PTL
-most important risk factor is prior hx of spont PTL
-cervical length (>30mm = low risk)
-fetal fibronectin
Fetal Fibronectin
*glycoprotein functioning to maintain intergrity of chorionic-decidual interface
in asympotomatic women:
-positive in cervicovaginal fluid @24 weeks predicted spont PTL (PPV =25%; NPV =96%)
PTL: Management Initial
-transfer to appropriate facility
-hydration, bed rest in LLDP, sedation, avoid pelvic exams
-U/S exam of fetus
-prophylactic abx (controversial)
PTL: Supppression of Labour (Tocolysis)
may buy time for transfer etc
Requirements:
-PTL
-live, immature fetus, intact membranes, cervical dilatation of ?4 cm
-absence of contraindications
Tocolysis Contraindications: Maternal
-bleeding (placenta previa or abruption)
-maternal disease (htn, dm, heart disease)
-pre-eclampsia or eclampsia
-chorioamnionitis
Tocolysis Contraindications: Fetal
-erythroblastosis fetalis
-severe congenital anomalies
-fetal distress/demise
-IUGR
-multiple gestation
Tocolytic procedure
*need appropriate personnel and equipment
Ca-channel blockers: nifedipine
PG synthesis inhibitors: indomethacin
?-mimetics: ritodrine, terbutaline
Use for only ?48 hrs
Enhancement of Fetal Pulmonary Maturity
betamethasone or dexamethasone
28-34 weeks GA: reduces incidence of RDS
24-28 weeks GA: reduces severity of RDS, overall mortality and rate of intraventricular hemorrhage (IVH)
Maternal contraindications: active TB, viral keratosis, maternal DM
PTL Prognosis
-leading cause of perinatal morbidity and mortality
-30 weeks or 1.5 kg = 90% survival
-33 weeks or 2 kg = 99% survival
-asphyxia, hypoxia, sepsis, RDS, IVH, thermal instability, retinopathy of prematurity, bronchopulmonary dysplasia
Premature Rupture of Membranes (PROM)
*rupture of membranes prior to labour at any GA
*amniorrhexis
Prolonged ROM
>24 hrs prior to onset of labour
Preterm ROM
ROM prior to 37 weeks GA
PPROM
preterm premature ROM
PROM Risk factors
Maternal: multiparity, cervical incompetence, infection, fam hx, low socioeconomic class/poor nutrition
Fetal: congenital anomaly, multiple gestation
see PTL risk factors too
PROM Investigations
sterile speculum exam:
-pooling of fluid in the posterior fornix
-fluid leaking out of cervix on cough
Nitrazine paper blue (+ with blood, urine or semen)
ferning
U/S: fetal anomalies, assess GA and BPP
PROM Management
-admit and monitor
-culture for GC and GBS
-assess fetal lung maturity
-weigh degree of prematurity vs. risk of amnioinitis and sepsis
-if not in labour or labour not indicated consider antibiotics
-deliver urgently if evidence of fetal distress and/or ch
PROM: prematurity
<24 weeks: consider termination
26-34 weeks: expectant management (prematurity complications high)
34-36 weeks: rds and neonatal sepsis risk is the same
>36 weeks: induction of labour
PROM: Prognosis
90% of women with PROM at 28-34 weeks go into spont labour within a week
50% of women with PROM at <26 weeks go into spont labour within a week
Complications: cord prolapse, intrauterine infection, premature delivery, limb contracture
Breech Presentation
Complete (10%): flexion at hips and knees
Frank (60%): flexion at hips, extension at knees; most common to be delivered vaginally
Footling (30%): may be single or double with extension at hip(s) and knee(s)