19. Preterm labor-diagnosis , management and treatment. Flashcards
what is preterm labour ?
the labor starts before the 37th completed week
what is premature birth ?
birth of fetus less than 37 gestation weeks ,
weighing between 500-2500g
Etiology of preterm labour ?
polyhydraminos (uterine stretch pathway initiated)
remain unknown
history of spontaneous abortion or preterm delivery
preclampsia
antepartum hemorrhage
mothers age lower than 16 - or over 40 years
vibration
pelvis : cervical incompetence malformed uterus recurrent urinary tract infections or asymptomatic bacteria tumors , uterine vaginal infections bacterial vaginosis
stress -
placenta and fetal membrane associated
PROM
placenta praaevia ,
placental abruption
fetus - congenital malformations , multiple pregnancies ,
Diagnosis for preterm birth
bleeding during first trimester and hyperemesis gravidarum
early signs - regular uterine contractions with our without pain atleast one every 10 mins lasting 30 seconds
dilation >2cm and effacement 80 percent of the cervix
pelvic pressure
increase vaginal discharge and sometimes accompanied by bleeding
then Alvarez contractions - frequent contractions with lower amplitude and
sometimes this cascade starts with premature amniotic fluid rupture before 37 weeks of gestation - in this case delivery is irreversible
latent phase is longer in preterm
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predictors
uterine contractions >4/hr
ishop score >4
cervical length through TVS <25mm
positive fibronectin (glycoprotein binding the fetal membrane to the decidua ) test at 24-34 weeks predicts a higher chance of preterm labour
negative - reassured that delivery will not occur within next 7 days
clinical management of preterm labour
strict observation of high risk patients - cardiotochograpphy
weekly evaluation of vertical status
TVS examination of the cervix
prophylaxis
iron containing pills for anemia
magnesium sulfate - for insufficiency
lighter regime , and taking rest
what are the prophylaxis of preterm labour ?
2) lydol (morphine like effect ) administered intramuscularly for 24 hours
cultures of vaginal and cervical flora immediate antiobiotic treatment of bacterial vaginitis - esp streptococcus
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threatening preterm miscarriage:
bed rest and hydration ringers solution
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sleeping on left side of the body improves uterine blood flow - ischemia is one of the causes of prostaglandin synthesis
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3) papaverinum hydrochloric - antispasmolytic - administered
intramuscular
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4) magnesium sulfuricum - administered in the course of 7 days
magnesium competes with calcium in a cellular level
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if still no change in cervical status then tocolysis is applied as short term therapy to delay it 1-3 days for fetal lung maturation:
5) tocolysis with beta adrenergic agonist - FENETEROL , TERBUTALINE
6) prostaglandin synthesis inhibitors -NSAIDs - aspirin
suppression of enzyme Cyclooxegenase
7) calcium antagonist - nifedipine
taken orally
stops entrance of calcium ions - decrease uterus contractions
8) oxytocin receptor antagonist
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corticosteroids - for prophylaxis of perinatal morbidity in less than 34 weeks gestation
betamethasone is steroid of choice
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Prophylactic cervical cerclage for women with prior preterm birth and short cervix
when is giving birth inevitable ?
cervical dilation over 3-4cm giving birth is inevitable
how do we assess lung maturation
concentration of lecithin and sphingomyelin can be measured by amniocentesis by thin layer chromatography
and expressed as L/S ration
RDS is rare with the L/S ratio is greater than 2 and PG (phsophatidylglycerol anther surfactant product) is present
when L/S ratio less than 2 and no PG present - more than 90 percent f infants develop RDS
complication of preterm fetus :
depending on its gestational age :
inadequate thermoregulation
reduced subcutaneous as well as brown fat and increased surface area
lack of suction reflex
hyperbilirubinemia as a result of undeveloped liver in labour CORD CLAMPED IMMEDIATELY TO AVOD THIS
hypoglycemia
oliguria and anuria
heart failure - PDA
hyaline membrane disease
periodic apnea attacks due to bad control of breathing
infections because the protective passive immunity obtained from the mother is less :
bronchopneumonia
meningitis
necrotising enterocolitis
intraventricular haemorrhages
cerebral haemorrhages - Soft skull bones allow dangerous degree of moulding leading to subdural or subarachnoid hemorrhage
RETINOPATHY ! - abnormal neovascularisation related to high conc of oxygen
side effects for calcium antagonist ?
tachycardia
contra for calcium antagonists
liver diseases
side effects for prostaglandin synths inhibitors -NSAIDs
prolonged bleeding time after delivery
side effects for beta adrenergic agonist
cardiovascular = reflex tachycardia , hypotension hypotonia , cardiac arrhythmia , myocardial ischemia ,
swelling of legs
metabolic =
hyperglycaemic , hyperinsulinemia ,
hypokalaemia,
acidosis
contra for beta adrenergic agonist
contra - cardiovascular disease of mother eclampsia preeclampsia severe vaginal bleeding intrauterine infections abrupt placenta chorioamniotitis IUGR fetal anomalies placenta previa
is vaginal delivery or c section preferred in preterm labour ?
vaginal delivery
preterm fetus less than 34 weeks with breech only indicated for c section
