Flashcards in USE THIS PRETERM Deck (66)
Define preterm labour + what source?
Labour between 24 and 37 weeks, with the onset of regular contractions associated with effacement + progressive cervical dilation - may or may not be ROM (MAYES p979)
What is the age of viability?
24 weeks but if >23 and estimated >400g and showing signs of life, resus often attempted
What happens in the last few weeks of pregnancy?
laying down of brown fat, sucking reflex and lung surfactant
What are late preterm babies at risk of?
hypoglycaemia, jaundice and RDS
In 2012 what was the incidence of premature babies?
What is the prematurity the biggest cause of?
neonatal mortality and morbidity
What are 75% of premature births a concequence of?
preterm spontaneous labour or secondary to PPROM
What causes the other 25% ?
elective decision to deliver the baby
What is the major long term consequence of premature birth?
What other things is premature birth associated with?
cerebral palsy, chronic lung disease
Behavioural and environmental risk factors 10
-smoking - pprom and iugr
-recreational drugs, alcohol
-poor nutritional status/malnourishment
-low bmi <19
-physically demanding work e.g. manual work - may be associated with lower socio-economic status
-prolonged periods of standing ?shift/night work
-abdo injury / trauma
-stress - catecholamine release
-cocaine - placental abruption
Demographic risk factors
-low socioeconomic status
-<17 years or >35 years
-ethnicity - ethnic minority in a developed country - unknown cause
Medical risk factors
What is antiphospholipid syndrome?
Disorder of the immune system that causes an increased risk of blood clots
What is important about infection and prematurity?
It can be the cause of the preterm birth or PPROM - usually assumed over >48 hr PPROM is the cause of infection but it may have caused the PPROM - always do a septic screen
Reproductive risk factors
inadequate antenatal care
-previous preterm labour
-previous >2nd trimester loss
-multiple pregnancy - if MCMA often delivered at 32 weeks to avoid twin to twin transfusion
-cervical abnormalities - sutures, previous lletz
-uterine abnormalities - bicornate, uterus with septum
-history of preterm labour
What is the incidence of PPROM?
How can preterm labour be prevented?
-encouraging a healthy lifestyle
-comprehensive antenatal care
-on-going risk assessment
-infection screening in pregnancy
-routine msu testing
What are the 2 most accurate markers to predict women at risk of preterm labour?
transvaginal USS of cervical length, measurement of cervicovaginal fetal fibronectin levels
What is cervicovaginal fetal fibronectin?
It is a protein found in amniotic fluid, placental tissue and the extracellular substance of the intervillous space. By 22 weeks, following fusion of chorion and decidua FFN secretion stops. Before labour starts, separation of chorion from decidua releases secretion of ffn. If the test is detected after 22 weeks it is a preterm birth indicator.
What are the results of the ffn test?
High negative and low positive
negative = 50ng/ml or less
Positive 50ng/ml or more
What causes ffn to become inaccurate?
presence of pprom or vaginal bleeding
What is the transvaginal uss for?
To measure cervical length- safe and acceptable test for women
- The normal average length of cervix at 24 weeks is 35.2mm +/- 8.3mm .
-in normal low risk pregnancies, the length remains constant until 3rd trimester
How can low socioeconomic status cause preterm labour?
associated with increased risk. prevention in this category involves preconception care including education on smoking cessation, better family planning and interpregnancy spacing, and financial support, alleviate poverty, partner education to reduce domestic violence
What is vaginal progesterone?
prophylactic treatment - inhibits uterine contractions and cervical ripening which prolongs pregnancy
-has been shown to reduce rates of ptb in women with a singleton pregnancy and hx of previous ptb, a short cx identified on tuss between 19-25 weeks
What is a cervical cerclage?
this is a suture placed around the cervix before or during pregnancy to correct structural weakness or defects
What is used when suspected preterm labour to diagnose?
Measurement of cervical length, fetal fibronectin
What is important in the care of preterm labour?
Antenatal corticosteroids - lung maturation
Nifedipine - usually antihypertensive but also tocolytic
Magnesium sulfate- lung surfactant production
How is fetal monitoring done for preterm birth?
if <28 weeks no ctg - for wellbeing of healthy term babies