O&G PRETERM DELIVERY, Tutorial for 2024 v1

Core Tutorials in Obstetrics & Gynaecology
PRETERM
BIRTH
Dr Roger Derham
FRCOG,FRCPI, MIOG,FMFFLM, FRAMI

PRETERM BIRTH
The diagnosis of preterm labour (PTL) is based on clinical criteria of documented
regular uterine contractions, together with cervical dilatation, withor without
rupture of fetal membranes (20 weeksto 37 weeks’ gestation).
WHO, (1977).

PRETERM BIRTH
According to the WHO approximately,in 2020, 13.4 million babies were born
worldwide < 37 weeks; equivalent to about 10% of all births, a slight reduction from
10.6% in 2010.
Globally:
4.2% of preterm births deliver < 28 weeks.
10.8% of preterm births deliver28 – 31+6 weeks
85% of preterm births deliver32 – 36+6 weeks
Ohuma EO et al. National, regional, and global estimates of preterm birth
in 2020, with trends from 2010: a systematic analysis
Lancet 2023: 402: 1261-71

PRETERM BIRTH
Lancet 2023: 402: 1261-71

PRETERM BIRTH
Newborn babies born preterm have substantially higher risks of adverse outcomes
compared with babies born at term. In addition to increased mortality preterm
delivery is associated in survivors with short-term and long-term effects, such as
poor health and growth, intellectual and mental disabilities, as well as early onset
of chronic diseases.
The risks of mortality and morbidity increase according to the degree of
prematurity, with babies born extremely preterm (<28 weeks of gestation) at the
highest risk, followed by babies born very preterm (28 weeks to <32 weeks), then
babies born moderate to late preterm (32 weeks to <37 weeks).
Lancet 2023: 402: 1261-71

PRETERM BIRTH
Ireland’s PRETERM birth rate in 2020 is 7% (an increase from 6% in 2011)
of these preterm births:
2.9% are born at <27 weeks gestation.
10.5% are born 27 – 31+6 weeksgestation
82.5% are born 32- 36+6 weeks gestation.
The PERINATAL MORTALITY RATE is 2.1/1000 live births for gestations ≥ 37 weeks.
The PERINATAL MORTALITY RATE is 67.5/1000 livebirths where gestation is < 37weeks

PRETERM BIRTH
The UK’s PRETERM birth rate (PTB) is about 8%
It is estimatedthat PTB costs the NHS in the England & Wales alone about
£3.4 billion per annum.

PRETERM BIRTH
RISK FACTORS FOR PRETERM BIRTH
MAJOR FACTORS:
PREVIOUS PRETERM DELIVERY
MULTIPLE PREGNANCY

PRETERM BIRTH
MAJOR FACTORS:
PREVIOUS PRETERM DELIVERY
Previous preterm birth
Previous PTB is the most significant risk factor for PTB. This association is modified by
three risk factors:
• the number of prior PTBs
• the gestational age at which the previous birth(s) occurred, and
• the order in which the prior PTB(s) occurred.
For example, the risk of PTB in the current pregnancy, with one previous PTB, is 15-20%,
after two PTBs it is 35-40% and with one preterm and a subsequent term birth the risk is
reduced to 10-15%.

PRETERM BIRTH
MAJOR FACTORS:
MULTIPLE PREGNANCY
50% of twin pregnancies willdeliverbefore 37 weeks. 10% will
deliver before 32 weeks.
Of note there is an increased rate of preterm delivery in singleton pregnancy
where previous pregnancy was a a preterm delivery of twins.
66% of TRIPLET pregnancies deliverbefore 34 weeks.

PRETERM BIRTH
OTHER RISK FACTORS:
Maternal Age < 18 years
Black ethnicity Interpregnancy interval <6 months
Strenuous Occupation BMI ≤ 19
Bacterial Vaginosis Chlamydia
Cocaine/Heroin Use Previous Cervical Cone Surgery
Short Cervix(<3 cm) Uterine Structural Anomalies/Ashermann’s Syndrome
Intrauterine Infection Medical Disorders:Thyroid, DM, Hypertension
Asymptomatic Bacteruria Non-Genital Infections:Appendicitis, Pneumonia
Peridontal Disease Vaginal Bleeding associated with APH and
Abnormal Placentation
Smoking DomesticViolence

PRETERM BIRTH
SURVEILLENCE FOR PRETERM BIRTH
Cervical length surveillance
Transvaginal sonography may be used to assess cervical length and the anatomy of
the internal os between 16 to 24 weeks. In low-risk women, cervical length is a
normally-distributed variable with a mean of 35-40mm from 14 to 30 weeks. Cervical
length is a good predictor of PTB for high risk women, with sensitivity of 60-80% and
PPV of 70% when cervical length is less than 25mm between16-18 weeks.
After 30 weeks of gestation, the cervix progressively shortens physiologically in
preparation for labour and thus it is not usual to rely on cervical length measurement
at this gestation and beyond for the prediction of spontaneous PTB in asymptomatic
women.

PRETERM BIRTH
PREVENTION OF PRETERM BIRTH
Consider prophylactic vaginal progesterone* for womenwho have a history of
spontaneous preterm birth (up to 34+0 weeks of pregnancy) or mid- trimester loss
(from 16+0 weeks of pregnancy onwards), irrespectiveof cervical length.
In addition:-
Offer cervical cerclage to womenwho have:
i. a current cervical length of 25mm or less and a history of PPROM
<34+0 weeks gestationin a previous pregnancy.
Offer cervical cerclage to women who have:
i. a current cervical length of 25mm or less
*Dose for progesterone: 200mg Cyclogest pessaries PV BD from 16-36 weeks

PRETERM BIRTH
PREVENTION OF PRETERM BIRTH – ARABIN Silicone Pessary
There was some initial evidence for the benefit of Arabin cervical pessaries in the preventative
management of preterm deliveries, either alone or in combination with progesterone. Recent
randomised trials ( with discretionary co-use of progesterone) in US of singleton pregnancies with cervical
length ≤20mm however show no benefit and indeed there was increased perinatal mortality in the
cervical pessary use arm of trial.

PRETERM BIRTH
CERVICAL CERCLAGE
History-indicatedcerclage is offered to asymptomatic woman electively between 12-14
weeks of gestation who have had:
i. Multiplemid-trimester losses or preterm births less than 34 weeks
ii. Successful pregnancy with a cerclage in situ previously
iii. Previous significant cervical surgery (cone biopsy/2 x LLETZ) and evidence of
cervical shortening in a pregnancy complicatedby preterm delivery
iv. When cervical length scanning has failedto identify at risk women in a previous
pregnancy
Cerclage is associated with increased risks of:
i. Maternal pyrexia
ii. bleeding
iii. small risk of bladder injury, cervical trauma, rupture membranes
iv. vaginal discharge which are of uncertain clinical significance

PRETERM BIRTH
Cervical Cerclage

PRETERM BIRTH
CERVICAL CERCLAGE
Rescue Cerclage
Rescue cerclage can be considered between 16+0 and 27+6 weeks in women with a
dilated cervix and unruptured membranes if there are no:
i. uterine contractions and established labour
ii. signs of infection
iii. bleeding
Contraindications to cerclage insertion:
i. Active preterm labour
ii. Clinical evidence of chorioamnionitis
iii. Continuing vaginal bleeding
iv. Preterm Pre-labour Rupture Of Membranes (PPROM)
v. Evidence of fetal compromise
vi. Lethal fetal defect
v. Fetal death

PRETERM BIRTH
CERVICAL CERCLAGE - insertion
Insertion is usually undertaken under spinal anaesthetic
Consider use of a foley catheter
Intraoperative antibiotics shouldbe given if membranes require manual manipulation
Placement of the knot, either anteriorly or posteriorly can be surgeon’s preference
Suture type is generally non-absorbable nylon.
CERVICAL CERCLAGE - removal
Cerclage should be removed in the event of PPROM.
Cerclage should be removed in women presenting in establishedpreterm labour to
minimise the risk of trauma to the cervix.
Cerclage or cervical pessary should be removed electively before labour, usually
after 37+0 gestation, unless delivery is by elective caesarean section, in which case
suture removal couldbe delayed until this time.
A plan for removal of cerclage or pessary shouldbe made at the time that it is
placed.

PRETERM BIRTH
INITIAL CLINICAL ASSESSMENT
Women presenting at less than 37 weeks gestation withPTL
should be triaged as a priority and evaluated by careful clinical
assessment by an experienced clinician to outrule possible
underlying causes of PTL. Streamlined medical care and decisions
on appropriate management is therefore crucial.

PRETERM BIRTH
INITIAL CLINICAL ASSESSMENT
Where a woman presents and preterm labour is suspected, a history should be taken and
the following examinations and investigations shouldbe performed. The woman should be
kept informedthroughout the process and consent gained.
1. Clinical information should be obtained, including:
i. Gestational age
ii. Possibility of ruptured membranes
iii. Onset, frequency and duration of contractions;with direct confirmationby
palpation
iv. Past obstetric history including: Mid-trimester miscarriages,pre-term
deliveries,vaginal bleeding/discharge
v. Antepartum haemorrhage
vi. Symptoms suggestive of generalisedinfectionor a urinary tract infection
(UTI)
vii. Major social disturbance/life events
viii.History of cone biopsy/ LLETZ/ other cervical surgery

PRETERM BIRTH
Initial assessment
Where a woman presents and preterm labour is suspected, a history should be taken and
the following examinations and investigations shouldbe performed. The woman should be
kept informedthroughout the process and consent gained.
2. A clinical examination should be performed looking for:
i. Evidence of infection – IMEWS
ii. Evidence of any abdominal pathology e.g. pyelonephritis
iii. Presence of any uterine tenderness and irritability
iv. Contractions – duration and frequency
v. Obstetric abdominal palpation – presentation, lie, level of presenting part,
amnioticfluid

PRETERM BIRTH
Initial assessment - INVESTIGATIONS
i. Speculum Examination/Vaginal Examination
i. Following exclusion of other causes of abdominal pain a sterile speculum examination
shouldbe performed with consent, to inspect for liquor and take HVS. (Use sterile water
as a lubricant NOT Hibitane® or gel)
ii. If there is no evidenceof preterm, prelabour rupture of membranes (PPROM) then
perform a Fetal Fibronectin (FFN) test. You do not perform a FFN test if gestation is less
than 22 weeks or >34+6 weeks; if there is PPROM, bleeding or a history of sexual
intercoursein the last 24 hours, or significant cervical dilatation. (Quantitative fetal fibronectin can be
used as a diagnostic test in symptomatic women to determine the likelihood of delivery within 48 hours for women who are 22+0 to
34+6 weeks, particularly when cervical length scan cannot be performed.
iii. If there is evidence of PPROM collect liquor using a quill or swab, send for culture
and sensitivities and manage as per PPROM guidelines.

PRETERM BIRTH
Initial assessment – INVESTIGATIONS INTERPRETATION
a. Quantitative fetal fibronectin:
Quantitative fetal fibronectin (fFN) can be used as a diagnostic test in symptomatic women to
determine the likelihoodof delivery within 48 hours for women who are 22+0 to 34+6 weeks,
particularly when cervical length scan cannot be performed. When the fFN test is positive it is a
predictor of preterm labour.
The fFN is secreted by fetal cells. It is found at the interface of the fetal sac and the uterine lining.
It is believed that the protein keeps the sac glued to the uterus. When considering intrauterine
transfer, a threshold value200 ng/ml. can be used.
The use of qualitative fetal fibronectin estimationand other near-patient tests such as placental
alpha macroglobulin-1 (PAMG-1,PartoSure) and insulin-like growth factor binding protein-1
(IGFBP-1, Actim Partus). PAMG-1 has a similar negativepredictive value to fFN but a slightly better
positive predictive value.

PRETERM BIRTH
Initial assessment – INVESTIGATIONS INTERPRETATION
Quantitative fetal fibronectin can be used as a diagnostic test in symptomatic women to
determine the likelihood of delivery within 48 hours for women who are 22+0 to 34+6 weeks,
particularly when cervical length scan cannot be performed. The use of qualitative fetal
fibronectin estimation and other near-patient tests such as placental alpha macroglobulin-1
(PAMG-1,PartoSure) and insulin-like growth factor binding protein-1 (IGFBP-1, Actim Partus),
are not currently recommended by NICE to diagnose preterm labour.
b. Cervical length scan
c. QUiPP app (available at https://quipp.org).
This is a risk-calculator which uses medical history and either cervical length, fetal fibronectin, or
both to compute a risk of birth If the risk of delivery within 1 week is <5% manage as unlikely
preterm labour and consider discharge. If the risk of delivery within 1 week ≥5% manage as likely
preterm labour. This can be personalised to patient and clinician preference.

PRETERM BIRTH
PRETERM LABOUR -
MANAGEMENT

PRETERM BIRTH
8 Care following diagnosis of preterm labour
Aims of obstetric components of antenatal optimisation, from British Association of Perinatal Medicine (BAPM)
(2019) Antenatal Optimisation Toolkit https://www.bapm.org/pages/194-antenatal-optimisation-toolkit
Treatment is aimed at:
• addressing the precipitating cause
• improving fetal outcome with the use of steroids and magnesium sulphate
• delaying delivery to enable corticosteroids/magnesium sulphate to act or permit in
utero transfer
• prevention of chorioamnionitis
8.1 Corticosteroids
Antenatal steroids are associated with a significant reduction in rates of neonatal
death, respiratory distress syndrome (RDS) and intraventricular haemorrhage and

PRETERM BIRTH
MANAGEMENT PRETERM LABOUR
CORTICOSTEROIDS FOR
FETAL LUNG MATURITY

PRETERM BIRTH
CORTICOSTEROIDS FOR FETAL LUNG MATURITY
Animal and human studies have shown that when glucocorticoids (such
as dexamethasone or betamethasone) are administered to women with
a high likelihood of preterm birth, they cross the placenta and enhance
the structural maturity of developing fetal lungs, including inducing
differentiation of mesenchymal tissue, accelerating production and
secretion of surfactant and decreasing vascular permeability, leading to
increased compliance and maximal lung volume. These changes can
prevent respiratory-related morbidity and mortality affecting preterm
newborns.
WHO recommendations on antenatalcorticosteroids for improving preterm birth outcomes.
Geneva:World Health Organization;2022.Licence: CC BY-NC-SA 3.0 IGO.

PRETERM BIRTH
The gestational age threshold for antenatal corticosteroid use remains clinically
important. At less than 34 weeks of gestation, there is compelling evidence of
reduced perinatal and neonatal mortality and respiratory-related morbidity.
However, after 34 weeks of gestation, there is no difference in mortality, a
modest reduction in respiratory morbidity, and increased neonatal
hypoglycaemia.
Vogel JP et al. Commentary on WHO 2022 Guidelines. www.thelancet.com/lancetgh Vol 10 December 2022

PRETERM BIRTH
1.0: Antenatal corticosteroidtherapy is recommendedfor women with a high likelihoodof
preterm birth1 from 24 weeks to 34 weeks of gestation when the following conditions are met:
i. Gestational age assessment can be accurately undertaken
ii. There is a high likelihoodof preterm birth within 7 days of starting therapy
iii. There is no clinical evidenceof maternal infection
iv. Adequate childbirth care is available(including capacity to recognize and safely
manage preterm labour and birth)
v. The preterm newborn can receive adequate care (including resuscitation,
kangaroo mother care, thermal care, feeding support, infectiontreatment and
respiratory support including continuous positive airway pressure [CPAP] as needed)
WHO recommendations on antenatalcorticosteroids for improving preterm birth outcomes. Geneva:World Health
Organization;2022.Licence: CC BY-NC-SA 3.0 IGO.

PRETERM BIRTH
1.1 Antenatal corticosteroidtherapy shouldbe administeredto women with a high likelihood
of giving birth preterm in the next 7 days, even if it is anticipated that the full course of
corticosteroids may not be completed.
1.2 Antenatal corticosteroidtherapy is recommendedfor women with a high likelihoodof
preterm birth, irrespectiveof whether single or multiple birth is anticipated.
1.3 Antenatal corticosteroidtherapy is recommended for women with preterm prelabour
rupture of membranes (PPROM) and no clinical signs of infection.

PRETERM BIRTH
1.4 Antenatal corticosteroid therapy is not recommended for women with chorioamnionitis
who are likely to give birth preterm.
1.7 Antenatal corticosteroid therapy is recommended for women with a high likelihood of
preterm birth of a growth-restricted fetus (IUGR).
1.10 A single repeat course of antenatal corticosteroids is recommended for women who
have received a single course of antenatal corticosteroids at least 7 days prior and, on clinical
assessment, have a high likelihood of giving birth preterm in the next 7 days.

PRETERM BIRTH
Tocolysis

PRETERM BIRTH
Tocolysis
Tocolytic therapy may be considered for women with confirmed PTL between 24 and 34 weeks’
gestation, where there is no contraindication to their use, and where a delay in delivery of the
newborn is likely to improve neonatal outcome. Those most likely to benefit are those in very
early PTL (less than 28 weeks’ gestation), where it may be prudent togain time to allow for
completion of corticosteroids & magnesium sulphate, and to allow for safe in-utero transfer from
a regional to tertiary-level hospitals with appropriate NICU facilities.
HSE GuidelineNo.22

PRETERM BIRTH
Tocolysis
All classes of tocolytic drugs (ie, betamimetics, calcium channel blockers, magnesium sulfate,
oxytocin receptor antagonists, and nitric oxide donors) and their combinations have some
effect in delaying preterm birth for at least 48 h, sometimes for 7 days.
Overall, three tocolytics—nifedipine, oxytocin receptor antagonists, and nitric oxide donors—
had the best benefit–risk profiles. Nitro oxide donors such as nitroglycerin however are not
routinelyemployed in preterm labour.

PRETERM BIRTH
Indications for tocolysis
i. Regular uterine contractions of at least 30 seconds duration at a rate of 4 per 30 minutes or
greater,
or
ii. cervical dilatation of 1-3cm and effacement of at least 50%.
Relative contraindications to tocolysis
i. less than 22+0 or more than 33+6 weeks gestation
ii. antepartum haemorrhage
iii. Chorioamnionitis/sepsis
iv. known hypersensitivity to the active substance or any of the excipients.
v. any other conditions in the mother or fetus in which continuation of the pregnancy would be
hazardous.
vi. Advanced cervical dilatation
vii. Fetal compromise (CTG/Doppler/Biometry) or intrauterine death.

PRETERM BIRTH
Tocolytic Drugs
NIFEDIPINE: Calcium channel blocker.
ATOBISAN (Tractocile): A competitive oxytocin & vaspopressin receptor antagonist inhibiting Ca++ flux.
Atobisan increasingly the drug of choice. Both calcium channel blockers (Nifedipine) and Atosiban have
similar efficacy in delaying pregnancy for up to 7 days but nifedipine may be more likely to delay delivery
for 48 hours.
Maintenance treatment with tocolytic drugs or repeat tocolytic treatment does not appear to improve
perinatal outcome and therefore is not recommended.

PRETERM BIRTH
Tocolytic Drugs
ATOBISAN (Tractocile): A competitive oxytocin & vaspopressin receptor antagonist inhibiting Ca++ flux.
Total duration of the treatment should not exceed more than 48 hours. Further cycles of treatment can
be used should contractions recur, and no more than three retreatments are recommended during a
pregnancy.
Atosiban Side Effects:
Common side effects (affecting less than 1 in 10):
Headache, dizziness, hot flushes, vomiting, tachycardia, hypotension, reaction at site
of injection, hyperglycaemia
Uncommon side effects (affecting less than 1 in 100 people)
Fever, insomnia, itching, rash
Rare side effects (affecting less than 1 in 1,000 people)
Postpartum haemorrhage
Serious allergic reactions

PRETERM BIRTH
Tocolytic Drugs
While its use for PTL is unlicensed(British National Formulary), it is commonly used
due to ease of oral administration and low cost. A review of ten trials, including
1,029 women, comparing oral nifedipinewith the beta agonist ritodrine, nifedipine
appeared to be more effective in delaying delivery before 34 weeks gestation
and for at least 7 days until delivery (RCOG 25, 26) with
a lower side effect profile than beta agonists.
HSE GuidelineNo.22

PRETERM BIRTH
Tocolytic Drugs
Initial dose of 20mg
Followedby three further doses of 20mg every 30 minutes if
contractions continue.
Maintenancedose is 20-40mg orally four hourly for 48 hours (no
more than 160mg/24 hours).
Caution with doses > 60mg
HSE GuidelineNo.22

PRETERM BIRTH
Nifedipine side effects:
The following side effects have been reported in at least 1% of patients:
Constipation, diarrhoea, dizziness or light-headedness, flushing,
headache, nausea.
Uncommon side effects:
altered cardiac conduction, cutaneous vasodilation, drug-induced
hepatitis, fluid retention, hypocalcaemia, hypoglycaemia, hypotension,
tachycardia, altered uteroplacental blood flow, tachycardia.
HSE GuidelineNo.22

PRETERM BIRTH
MAGNESIUM SULPHATE for
FETAL NEUROPROTECTION

PRETERM BIRTH
MAGNESIUM SULPHATE for FETAL NEUROPROTECTION
Meta-analyses of randomised controlled trials have demonstrated that the administration
of magnesium sulfate (MgSO4) to women in established preterm labour or having a planned
preterm birth in the following 24 hours, reduces cerebral palsy (RR 0.69, 95% CI 0.55–0.88)
and motor dysfunction in the offspring (RR 0.6, 95% CI 0.43–0.83). The benefit is greatest
before 30+0 weeks of gestation.
The neuroprotective effect of magnesium sulfate in women with PPROM has also been
demonstratedin a cohort study.
The RCOG and NICE G25 recommend offering magnesium sulfate to women at risk of giving
birth before 30+0 weeks of gestation. NICE G25 also recommends that magnesium sulfate
should be considered when preterm birth is anticipated between 30+0 and 33+6 weeks.
RCOG GT no.73.

PRETERM BIRTH
Quantitative fetal fibronectin can be used as a diagnostic test in symptomatic women to
determine the likelihood of delivery within 48 hours for women who are 22+0 to 34+6 weeks,
particularly when cervical length scan cannot be performed. The use of qualitative fetal
fibronectin estimation and other near-patient tests such as placental alpha macroglobulin-1
(PAMG-1,PartoSure) and insulin-like growth factor binding protein-1 (IGFBP-1, Actim Partus),
are not currently recommended by NICE to diagnose preterm labour.
b. Cervical length scan
c. QUiPP app (available at https://quipp.org).
This is a risk-calculator which uses medical history and either cervical length, fetal fibronectin, or
both to compute a risk of birth If the risk of delivery within 1 week is <5% manage as unlikely
preterm labour and consider discharge. If the risk of delivery within 1 week ≥5% manage as likely
preterm labour. This can be personalised to patient and clinician preference.

PRETERM BIRTH
PRETERM PRELABOUR
RUPTURE OF MEMBRANES

PRETERM BIRTH
NICE (UK) GUIDANCENo.25 PRETERM LABOUR ANDBIRTH 2022
Preterm labour and birth
Guideline summary

PRETERM BIRTH
Preterm prelabour rupture of membranes (PPROM) complicates up to 3% of pregnancies and
is associatedwith 30– 40% of preterm births.
PPROM can result in significant neonatal morbidity and mortality, primarily from prematurity,
sepsis,cord prolapse and pulmonary hypoplasia. In addition, there are risks associated with
chorioamnionitis and placental abruption.
In regard to sepsis/chorioamnionitis associated with PPROM NICE (UK) recommends that a
combination of
i. clinical assessment (pulse, blood pressure, temperature and symptoms),
ii. maternal blood tests (C-reactive protein and white cell count) and
iii. Fetal assessment (fetal heart rate using cardiotocography,)
shouldbe employed to diagnose clinical infectionand should not be used in isolation.
PPROM AND PRETERM LABOUR

PRETERM BIRTH
If there is clinical evidence of chorioamnionitisor maternal sepsis, a septic
work-upshould be obtained and broad spectrum intravenous antibiotics
commenced.
The choice of antibiotics used can be determinedlocally but should
include appropriate coverfor GBS, E. coli, Listeria and anaerobes.
Delivery is indicatedin the management of chorioamnionitis.
HSE PPROM

PRETERM BIRTH
Women with PPROM and uterine activity who require intrauterine transfer
or antenatal corticosteroids may be considered for a short course of
tocolysis.
This decision needs to be considered in light of the possibility of pre-
existing intrauterine infection, the only clinical feature of which might be
uterine activity. If there is a significant suspicion of chorioamnionitis, then
tocolysisis not recommended.
HSE PPROM

PRETERM BIRTH
Following the diagnosis of preterm prelabour rupture of the membranes, (PPROM)
an antibiotic (preferably erythromycin) should be givenfor 10 days or until the
womanis in established labour (whichever is sooner).
Women whose pregnancy is complicated by PPROM after 24+0 weeks’ gestation
and who have no contraindications to continuing the pregnancy should be offered
expectant management until36+6 weeks; timing of birth should be discussed with
each woman on an individual basis with careful consideration of patient preference
and ongoing clinical assessment.
In womenwho have PPROM and are in established labour or having a planned
preterm birth within 24 hours, intravenous magnesium sulfate should be offered
Between 24+0 and 29+6 weeks of gestation.
RCOG GT No.73

PRETERM BIRTH
Perinatal Management of
Extreme Preterm
Birth at the Threshold of
Viability
HSE/RCPI/IOG Guidance 2022

PRETERM BIRTH
MANAGEMENT PRETERM LABOUR 23 – 24+6 WEEKS GESTATION
GENERAL GUIDANCE
A change in the threshold of fetal viability from 24+0 weeks to
23+0 weeks gestation has been accepted.
Initiation of life sustaining treatment is not recommendedfor
infants born less than 23+0 weeks’ gestation.

PRETERM BIRTH
ANTENATAL STEROIDS
The evidence for the use of antenatal steroids is robust. At 23
weeks’ gestation, death or impairment is reduced from 90.5%
to 83.4%, at 24 weeks from 80.3% to 68.4%, and 25 weeks from
67.9% to 52.7%.
Dexamethasone/Betamethasone 12mgs intramuscular, two
doses, 12 hours apart if time allows.

PRETERM BIRTH
ANTENATAL MAGNESIUM SULPHATE
Magnesium sulphate is recommendedfor women between
23 and 32+0 weeks’ gestation who are in establishedpreterm
labour or those having a planned preterm labour within 24
hours.
The initial dose is a 4g intravenous bolus followedan
intravenous infusionof 1g per hour until birth or for 24 hours.

PRETERM BIRTH
DELIVERY
Caesarean section is commonly considered less traumatic for preterm
infants but the evidence is not robust.
Routine caesarean section is not recommendedfor a
periviablegestation birth alone as it has not been shown to improve
survival.
Preterm labouris frequently associated withmalpresentation. At
gestations under 28 weeks the lower uterine segment is not well
formed. A transverse incision of the upper segment may be
necessary. This is associated with increased blood loss, increased post-
operative morbidityand increased risk of scar dehiscence in a future
pregnancy.

PRETERM BIRTH
Delayed cord clamping:
Delayed cord clamping is recommendedfor preterm births < 32 weeks’
gestation. The usual interval between infant birth and period of delayed cord
clamping is 60 seconds whereas immediate cord clamping is 5 seconds.
In term infants, 80 mls of blood is transferred from the placenta to the infant in
the first minute with only a small additional amount after that time. The
amount transferred to a preterm infant would be proportionately less.

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