Parto pre-termo

Question 1

Def

Answer 1

• delivery that occurs prior to the completion of 37 weeks of gestation (36w+6d )
• Preterm labor is defined as the presence of regular uterine contractions ( 4 contractions /20 min or 8 contractions/60 min) before 37w of gestation associated with cervical changes (effacement ≥80% and /or dilation <2cm).
• Early preterm birth : <28w
• Late preterm birth : 34w+0d-36w+6d
• Preterm birth is the leading cause of perinatal morbidity and mortality.
• The second leading cause of deaths among children under the age of 5 years
• Morbidity associated with PTB results in enormous economic and social costs

Question 2

Prevalência

Answer 2

• Europa: 5-7% (PT- 8%)
• USA: 11%
• Africa- 18%

Question 3

Complicações

Answer 3

o respiratory distress syndrome
o intraventricular hemorrhage
o necrotizing enterocolitis
o sepsis
o neurologic impairment
o seizures 

• 26-28 semanas: 1 dia a mais na gravidez implica menos 3% de risco de sequelas

Question 4

Causas

Answer 4

• Não esta bem definido
• Inflamação, hemorragia decidual, distensão patológica uterina, ativação do eixo HHSupra materno/fetal
• Causa precisa está inexplicável em >50%

Question 5

FR

Answer 5

o Prior history of preterm birth
o Preterm uterine contractions
o Premature preterm rupture of membranes 
o Behavorial risk factors 
. Low maternal prepregnancy weight
. Smoking
. Substance abuse
. Short interpregnancy interval 
o Current pregnancy factors
. Short cervical lenght
. Multifetal gestation
. Vaginal bleeding
. Urinary tract infections
. Genital tract infections
. Periodontal disease

Question 6

DX

Answer 6

• Deteção precoce de FR
• Sinais e sintomas
  o Menstrual-like cramps,
  o Low, dull backache
  o Abdominal pressure
  o Abdominal cramping
  o Increase or change in
  vaginal discharge
  o Uterine contractions
• Avaliação na suspeita de PPT
• Pelvic evaluation : the status of the cervix either by visualization with a speculum or by gentle digital examination
• LAB:
  o Urinalysis
  o Urine culture
  o Vaginal / rectal culture for GBS
  o Cultures for Chlamydia trachomatis and Neisseria gonorrhoeae ( when indicated)
  o Partosure (presença de prot entre o corio e a decidua e se tiver no fundo de saco -> bom valor preditivo neg nos 7 dias a seguir a fazer o teste)
• External electonic fetal monitor (CTG)
  o quantify the frequency and duration of contractions

- ECO
o Assessing gestational age of the fetus
o Amniotic fluid volume 
o Fetal presentation
o Placental location 
o Lenght of the cervix ( <28 s ) - entre o orifício interno e externo - quando inf a 25 mm temos risco elevado de ter parto antes das 34 sem

Question 7

Gestão

Answer 7

• Detection and treatment of disorders associated with preterm labor (infeção, etc)
• TX:

o Corticosteroids (reduce the incidence and severity of fetal respiratory distress syndrome , the intraventricular hemorrhage and the necrotizing enterocolitis
. 24 – 34 weeks of gestation ( betamethasone/ dexamethasone)
. single course
. maximal benefit : next 7 days period

o Tocolytics (allows  enough time of corticosteroid terapy to accelerate fetal lung maturation (48H) and maternal transport to a tertiary center 
. Calcium-channel blockers ( nifedipine) ->prevents calcium entry into muscle cells; EA: Maternal side effects : dizziness, flushing, hipotension and elevation of hepatic transaminases;  Fetal or Newborn adverse effects : not know ; CI: hipotension, cardiac failure and 		aortic insufficience -> são as mais utilizadas

. Nonsteroidal anti-inflammatory drugs-> indometacina -> decreases Pg production; EA mãe: nausea, esophageal reflux, gastritis; feto: constriction of ductus arteriousus, oligohydramnios; CI: platelet dysfunction bleeding, hepatic dysfunction -> Importante abaixo das 32/28 sem (NÃO DEVE SER USADO ACIMA DAS 32 SEMANAS)

. β-Adrenergic receptor agonists

. Antagonists of oxytocin receptor -> atosiban -> EA mãe/feto: desconhecidos a presença-> unica que foi desenhada para ser tocolítico (abaixo ds 28 sem eficacia inf a indometacina, EV, custo superior)

o Neuroprotection-> Magnesium sulfate (24 -32w) : lower the risk of developing cerebral palsy

Question 8

CI a tocolise

Answer 8

o Intrauterine fetal demise
o Lethal fetal anomaly
o Non reassuring fetal status 
o Severe preeclampsia or eclampsia 
o Maternal bleeding with hemodynamic instability 
o Intra-amniotic  infection
o PPROM
o Maternal contraindication to tocolysis

Question 9

Prevenção

Answer 9

• 2 apresentações tipicas:

o Spontaneous ( 40 a 50% PTB with intact membranes; 25 a 30% from PPROM)

o Indicated ( 20 a 30% )

• The majority of PTB > 34 s are iatrogenic (maternal or fetal indications)

- Prevenção primária (FR):
 o early detection and treatment of UTI
o weight gain during pregnancy
o healthy life style ( stop smoking)
o lower multiple pregnancy

• Cérvix curto ( congénito, conização, doença cervix, infeção, defice progesterona)
  o Vaginal ultrasound is the gold standard :
  . cervix < 25mm – increased the risk PTB before 34 w
  Funneling , sludge
  o TX:
  . progesterona vaginal (quando não há contrações) diminui a idd parto e a morbilidade conjunta no PPT
  . Cerclage (fios no orificio int do colo para reforçar o colo- via vaginal ou abd)
  . Pessário de Arabin (peça para reforçar o colo)