Preterm Labour and PPROM Flashcards
What is preterm labour?
Birth before 37 weeks
Mayes 2012
Incidence of preterm labour
Around 7% of births in the UK are preterm
Mayes 2012
What percentage of neonatal deaths is preterm birth responsible for?
75-90%
Mayes 2012
Types of prematurity
Extreme prematurity = less than 28/40
Severe prematurity = 28 to 31+6
Moderate prematurity = 32 to 33+6
Late maturity = 34 to 36+6
Biological and medical risk factors for preterm delivery
Age less than 16 or more than 35 Low BMI Chronic medical conditions such as diabetes or renal disorders Infections like UTI’s (Mayes 2012)
Reproductive history risk factors for preterm delivery
History of previous preterm birth
Bleeding in previous pregnancy
Uterine abnormality such as bicornuate
(Mayes 2012)
Current pregnancy risk factors for preterm delivery
Poor nutrition- especially with pre-pregnancy BMI less than 19.8 Bleeding Retained intrauterine contraceptive device Abdominal surgery Infections Genital tract infections Multiple pregnancy Polyhydramnios Fetal malformation Rhesus disease Fetal death Violence - including verbal, may cause fourfold increased risk Hypertensive disease (Mayes 2012)
Socioeconomical risk factors for preterm delivery
Poverty and social deprivation
Employment that involves hard physical work
Psychology distress
(Mayes 2012)
Cultural and behavioural risk factors for preterm delivery
Cigarette, alcohol and drug abuse Short inter-pregnancy interval Late antenatal booking Poor attendance for antenatal care (Mayes 2012)
Prevention of preterm labour
Encourage a healthy lifestyle
Comprehensive antenatal care
Ongoing risk assessment
Infection screening including MSU
Possible signs of preterm labour
Menstrual like cramps Signs of UTI Backache Pink vaginal secretions Diarrhoea Pelvic pressure or increased vaginal discharge (Mayes 2012)
Fetal fibronectin test
Is a diagnostic test to determine likelihood of birth within 48 hours for women who are 30+0 weeks pregnant or more. Is positive is over 50 ng/ml
(NICE 2015)
When can’t you perform a fetal fibronectin test?
In the presence of vaginal bleeding or ruptured membranes as both blood and amniotic fluid contain fibronectin
(Mayes 2012)
What are tocolytic agents
Used to suppress uterine activity in an attempt to allow the fetus to grow for longer in utero
(Mayes 2012)
Factors to consider when making a decision about starting tocolysis
Whether the women is suspected or diagnosed preterm labour
Clinical features like bleeding or infection which may contraindicate stopping labour
Gestational age at present
Likely benefit of corticosteroids
Availability of neonatal care - may need to transfer to another unit
Preference of the women
(NICE 2015)
What gestation should tocolysis be considered?
24+0 to 33+6
NICE 2015
What drug should be used for tocolysis?
Nifedipine is preferable as has few adverse effects with comparable effectiveness. It is a calcium blocker which reduces muscle contraction by controlling the influx of calcium across the plasma membrane
(Mayes 2012)
Advised by NICE (2015) and if contraindicated offer oxytocin receptor antagonists for tocolysis
Nifedipine
By mouth initially 20mg, followed by 10-20mg 3-4 times a day, adjusted according to uterine activity
(BNF 2019)
Evidence for corticosteroid therapy
A Cochrane meta analysis of 18 RCT indicated that it helps reduce the incidence of respiratory distress syndrome, neonatal death and intraventricular haemorrhage
(Mayes 2012)
What gestation to offer corticosteroids?
23+0 to 23+6 = discuss with women and consider individual circumstances
24+0 to 25+6 = consider corticosteroids
26+0 to 33+6 = offer maternal corticosteroids
34+0 to 35+6 = consider
(NICE 2015)
What drug is typically given when administering corticosteroids?
Betamethasone is the steroid of choice
Two 12mg doses IM 12 hours apart
(Mayes 2012)
What do corticosteroids do?
Accelerates surfactant production in the fetal lungs. Is effective after 24 hours and for up to 7 days. Most benefit between 24 to 32 weeks
(Mayes 2012)
What does magnesium Sulphate do?
A Cochrane review (2009) showed mag sulph to reduce maternal fits but also has a positive effect on the babies neurological development. Shown to reduce risk of cerebral palsy and reduce the risk of gross motor function disturbances. No significant effect on mortality or other neurological disabilities
Magnesium sulphate dosage
Loading dose of 4g given intravenously over 5 minutes then a maintenance dose of 1g/hr until delivery or 24 hours
(NICE 2015)
What to do if preterm labour continues?
Inform obstetrician nd paediatrician
Mayes 2012
What is Magnesium toxicity
Magnesium sulphate is excreted into the kidneys. Magnesium toxicity is unlikely to occur but if the women is oliguric (<100mls in 4 hours) or has renal impairment, the kidneys will not excrete magnesium efficiently and is then Magnesium levels more likely to be toxic.
(Prompt 2017)
What to do in the case of magnesium toxicity?
Administer only the loading dose. If the women develops oliguria while recieving the maintaince infusion, should be stopped and blood should be taken to measure the serum magnesium level
(Prompt 2017)
What should the serum magnesium level be for therapeutic range for magnesium sulphate treatment?
2-4 mmol/L
Prompt 2017
When to start magnesium sulphate emergency protocol?
When there is maternal collapse and cardiopulmonary arrest on magnesium sulphate
(Prompt 2017)
Magnesium sulphate emergency protocol
- Stop magnesium sulphate infusion
- Start basic life support
- Give 1g calcium gluconate IV (10ml of 10% solution
- Intubate early and ventilate until respiration resumes
(Prompt 2017)
What are preferred methods of pain relief in preterm labour?
Epidural and entonox as have no adverse effects on fetus
Mayes 2012
Why are infants at more risk of intracranial injury?
Poor ossification of the fetal skull, however no evidence for routine episiotomy or elective forceps
(Mayes 2012)
Why should ventouse be avoided?
Risk of vascular rupture and subsequent haemorrhage in an immature infant
(Mayes 2012)
PPROM
Spontaneous rupture of membranes before 37 weeks and before labour commences (preterm pre-labour rupture of membranes)
(Mayes 2012)
Risks associated with PPROM
Maternal smoking Vaginal bleeding in the second trimester Cervical incompetence Genital tract infection (Mayes 2012)
Confirming PPROM
A speculum can confirm by a pool of amniotic fluid being seen in the posterior fornix
(Mayes 2012)
What bloods should be taken once PPROM confirmed?
Taken to estimate WBC count and for serum screening for CRP
Mayes 2012
When can women be offered to go home after PPROM confirmed and what should they do?
If stable after 48 hours. Ask women to observe for signs of chorioamnionitis by twice daily temps, observing vaginal loss and to return to hospital for regular assessments
(Mayes 2012)
Antibiotics given for confirmed PPROM
Erythromycin given 250mg QDS for 10/7 or until labour orally
(NICE 2015)
