Preterm labour Flashcards
Risk of cerebral palsy with preterm birth 22-27 weeks
14.6%
Risk of cerebral palsy with preterm birth 28-31 weeks
6.2%
Risk of cerebral palsy with preterm birth 32-36+6 weeks
0.7%
Risk of cerebral palsy with preterm birth at term
0.1%
What is the risk of preterm birth in a future pregnancy after one preterm birth?
15-20%
What is the risk of preterm birth in a future pregnancy after 2 preterm births?
35-40%
What are the modifiable epidemiological risk factors for spontaneous preterm birth?
Low BMI, interpregnancy interval of <1year, smoking
What are the non-modifiable epidemiological risk factors for spontaneous preterm birth?
Teenage multiparous or advanced maternal age, nulliparity/multiparity, low socioeconomic status, unemployment, low education, minority ethnicity
What are the aetiological factors that may contribute to spontaneous preterm birth?
1) Inflammatory: Subclinical local infection or systemic infection/intercurrent illness
2) Uterine overdistension (polyhydramnios/multiple pregnancy)
3) Vascular (abruption)
4) Uterine abnormality (unicornate)
5) Cervical incompetence (history of previous surgical surgery)
What is the maximum timeframe that patients will benefit from steroid injections when administered for suspected preterm delivery?
24 hours to 7 days after the second dose
Incidence of preterm birth in the UK (before 37 weeks)
8 in 100 babies
Nice guidance [NG25] - what history and investigations would indicate recommendation of either vaginal progesterone or prophylactic cerclage?
History = spontaneous preterm birth <34 weeks or late pregnancy loss >16 weeks
AND
Investigation = cervical length <25mm on TVUSS between 16-24 weeks
If the patient only has either the history OR the investigation finding then NICE recommends vaginal progesterone instead of cerclage
NICE guidance [NG25] - what investigation finding would prompt you to consider offering cervical cerclage in a patient with previous history of PPROM or cervical trauma?
TVUSS showing cervical length <25mm between 16-24 weeks
At what gestation is cervical length of <25mm an indication for offering prophylactic treatment for preventing preterm labour?
16-24 weeks
If a patient is started on vaginal progesterone, how long dose NICE recommend continuing it?
Start between 16-24 weeks and continue until at least 34 weeks (this is off licence)
NICE guidance [NG25] - management of incidental finding of cervical length <25mm between 16-24 weeks but no history of late miscarriage, preterm birth, previous PPROM or cervical trauma
Offer vaginal progesterone from 16-24 weeks until at least 34 weeks (this is off licence use)
What protein is detected by a ROM test?
Placental alpha microglobulin 1 (PAMG-1)
NICE guidance [NG25] - which antibiotic course is recommended for confirmed spontaneous PPROM in a patient not in labour?
Erythromycin 250mg QDS for maximum of 10 days
NICE guidance [NG25] - when is rescue cerclage contraindicated?
Bleeding, infection, Contractions
NICE guidance [NG25] - when do NICE recommend that a rescue cerclage can be considered
Dilated cervix, unruptured membranes at 16-27+6/40
What are the contraindications for a fetal fibronectin swab?
Bleeding, SROM, lubricating gel, digital examination, sexual intercourse in last 24 hours, gestation <24 and >34 weeks, >3cm dilated
NICE guidance [NG25] - which tests do NICE recommend for a woman suspected of preterm labour >30/40 gestation?
TVUSS OR FFN
TVUSS - if cervix <15mm treat as TPTL
FFN if positive >50ng/ml treat as TPTL
What are the contraindications to tocolysis?
bleeding and infection
What does NICE recommend as first line tocolytic agent?
Nifedipine ( this is an off label use)
NICE guidance [NG25] - which gestation does NICE recommend tocolysis should be “considered” and when do they recommend it should be “offered”?
Considered- Threatened preterm labour 24-25+6/40
Offered - Threatened preterm labour 26-33+6/40
NICE guidance [NG25] - Which gestation dose NICE recommend corticosteroids should be “offered” and when do they recommend they should be “considered”?
“offered” - suspected del within 48 hours 24-33+6/40
“considered”- suspected del within 48 hours 34+0-35+6/40
NICE guidance [NG25] - which gestation does NICE recommend MgSO4 should be “offered” for neuroprotection and when do they recommend it should be “considered”?
Offer - 24-29+6
Consider- 30-33+6/40
NICE guidance [NG25] - which gestation does NICE recommend avoiding an FSE?
Below 34/40
NICE guidance [NG25] - which gestation does NICE recommend avoiding FBS?
Below 34/40
NICE guidance [NG25] - in what circumstance does NICE recommend considering c-section in PPROM or Preterm delivery?
Breech 26-36+6/40
What is the rate of survival for babies with extreme prematurity?
53% 22-26 weeks gestation
Overall incidence of preterm labour in the UK
5-10%
How often does infection cause preterm labour?
20-40% of cases
If a woman has had previous cervical surgery, what factors would prompt cervical length measurements by TVUSS in pregnancy?
LLETZ with a depth of >20mm
TWO or more LLETZ procedures
How are cervical length measurements performed?
TVUSS, empty bladder, sagittal view from internal os to external os, if funneling from the function internal os to the external os
What is the sensitivity and specificity of cervical length screening in patients with a history of previous preterm labour?
60% if performed in a singleton pregnancy
NICE guidance [NG25] - which gestation does NICE recommend cervical length by TVuss (if available) for patients presenting in TPTL?
TPTL after 30/40 - if <15mm NICE recommends offering steroids and tocolysis
What does cochrane say about the treatment of asymptomatic BV and bacteriuria and its impact on preterm birth?
Cochrane reviews found no decrease in preterm birth from treatment of bacterial vaginosis or asymptomatic bacteriuria
20-24 weeks pregnant, cervical length <25mm but >20mm, what is the risk of preterm delivery?
25% before 28 weeks
20-24 weeks pregnant, cervical length <20mm, what is the risk of preterm delivery?
42% before 32 weeks
62% before 34 weeks
