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Flashcards in USE THIS PRETERM Deck (66)
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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?

neurodevelopmental disability


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
-domestic violence
-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

-infection -40%
-renal disease
-cardiovascular disease
-antiphospholipid syndrome
-psychiatric disorders


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

-placental abruption/aph
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


What is the ideal cord clamping for preterm babies?

30 seconds