Preterm Birth

Question 1

Epidemiology of preterm birth

Answer 1

-8-10% births are preterm
=Iatrogenic (induce labour, caesarean, for maternal ill health or foetal abnormality), spontaneous
=53, 000 in UK each year

-Leading cause of perinatal morbidity and mortality
=Leading cause of death in children <5 yrs
-Massive financial implications – NNU care
-Traumatic for parents

Question 2

Definition of preterm labour

Answer 2

-Painful uterine contractions/activity (regular)
-Cervical dilatation and effacement
-Before 37 weeks

Question 3

Causes of preterm labour

Answer 3

-Idiopathic
-Infection (local genital tract, nearby inflammatory/ systemic or sepsis and influenza)
-Placental
-Cervical weakness- treatments traumatic, connective tissue (early birth)
-Multiple pregnancy
-Preterm rupture of the membranes
-Uterine anomaly (bicornuate, duplication)
-Obstetric cholestasis
-Congenital anomaly
-Polyhydramnios
-Intrauterine adhesions
-Fibroids (multiple, distend and distort uterine cavity, growth in pregnancy and die off- late miscarriage)

Question 4

Triage for preterm labour

Answer 4

-History and examination
=Observations- MEWS
=Urinalysis
-Palpate the abdomen, speculum/VE
-Listen to foetal heart, CTG

Question 5

Management of preterm labour

Answer 5

-Admit to Labour ward
-CTG – Continuous Electronic foetal monitoring CEFM (heard at 28 weeks)
-Scan for orientation/ lie/ presentation (more likely breech than full term)
-Venous access, Blood Transfusion sample, inflammatory marker – WCC, CRP
-Infection screen – MSU and HVS or LVS (low vaginal swab)
-IV ab (high chance of infection involvement, cover group B strep)
-IM steroids
=12mg beta or dexamethasone im x 2 now and in 24 hours (to mature baby’s lungs preventing RDS and Necrotising enterocolitis, IVH)
-Let paediatricians know – come to see her, make sure cot

Question 6

What if the patient has diabetes?

Answer 6

-Admit to Labour ward
-CTG – CEFM
-Scan
-Venous access, BTS, inflammatory markers etc
-IV ab
-IM steroids
=12mg beta or dexamethasone im x 2 now and in 24 hours –INSULIN/DEXTROSE SLIDING SCALE, stay on background as well
-Let paediatricians know – come to see her

Question 7

How to stop contractions

Answer 7

-Beta agonists e.g. terbutaline – s/c or nebulised (more frequent contractions- 6: 10, in full-term labour)
-Calcium channel blockers - oral (nifedipine)
-NSAIDS - oral
-Magnesium sulphate for fetal neuroprotection
-Oxytocin antagonists – e.g. atosiban

Not usually used as no change to baby outcomes
=Used to give time to transfer hospitals/ theatres for cervical suture/ steroid course completed

Question 8

What is tocolysis?

Answer 8

-In utero transfer to different hospital, usually 28 weeks and below/ in general pre-term
-Maybe complete steroids
-Consultant decision, if enough time

Question 9

Management at 28 weeks gestation

Answer 9

-Magnesium sulphate for fetal neuroprotection
=4g loading dose IV over 15 mins
=And Ongoing infusion 4-24 hours at 1g/hr
-50% reduction in cerebral palsy
-Any anticipated birth < 30 weeks

Question 10

What if she has a long closed cervix when we examined her?

Answer 10

-Scan cervix with transvaginal USS
-Fetal fibronectin swab from posterior fornix (glycoprotein; glue that holds amnion and chorion together)
=Negative (below 200) – 99% assurance will not deliver in next two weeks

Question 11

Describe preterm labour in hospital/ general

Answer 11

-In hospital
-Steroids before 34+6 weeks
-Mag sulphate before 30 weeks
-CEFM (continuous electronic fetal monitoring
-Paeds
-IV AB - benzylpenicillinc ( group B Streptococcus)
-Check presentation
-Consider causes – MSU, HVS etc
-Deferred cord clamping

Question 12

Doses of steroids and magnesium sulphate

Answer 12

Dexamethasone / Betamethasone 12mg IM 24 hours apart
Prescribe 1x Stat and 1x Regular (1 dose)Magnesium Sulphate 4g loading dose (Stat)Magnesium sulphate 1g/hour (for 24 hours / until birth of baby)

Question 13

What do we look for in speculum exam?

Answer 13

-Exclude infection
=Urinalysis, send MSU, HVS, FBC, CRP
-Cerclage/ suture/ stitch

Question 14

Emergency/ rescue management for cervical insufficiency

Answer 14

-Head down tilt for gravity
-Poke membranes back in
-Cervical Stitch

Question 15

Aetiology and incidence of cervical insufficiency or weakness

Answer 15

-Aetiology
=Functional defect
=Structural defect

-Incidence
=<1% obstetric population
=8% mid trimester losses
=? Proportion of preterm delivery - - very early

Question 16

Causes of 2nd trimester miscarriage

Answer 16

-Antiphospholipid syndrome
-Inherited thrombophilic defects
-Infection
=BV in first trimester
-Uterine anomalies
-Cervical Weakness
-Fetal abnormality
-Multiple pregnancy

Question 17

Investigations in 2nd trimester miscarriage

Answer 17

-Antiphospholipid antibodies
=Lupus anticoagulant
=Anticardiolipin Ab IgG and IgM
-Pelvic USS
=Hysterosalpingography
=3D USS/(MRI)/hysteroscopy+/-laparoscopy
-Inherited thrombophilias
=Factor V Leiden
=Factor II (prothrombin gene mutation)
=Protein S
-Post mortem and placental pathology, cytogenetics

Question 18

USS regime in monitoring

Answer 18

-1 LLETZ
=1 x Cx length with FA scan
-2 or more LLETZ
-cone biopsy
-1 or more preterm birth/PPROM
=Fortnightly cx length 16-24 weeks ( + LVS / HVS, MSU)

Question 19

Preventing preterm birth

Answer 19

-Aspirin for placenta
-Singleton pregnancy and short cervix/ pre-term birth previously= progesterone
-1st trimester miscarriage doesn’t work but is useful when recurrent miscarriage= progesterone

Question 20

Treatment of cervical insufficiency

Answer 20

-Cervical Cerclage
-McDonald (suture= transvaginal)
-Schirodkar (suture= high transvaginal)
-Transabdominal
=Laparoscopic
-Bed rest
-Arabin Pessary

Question 21

Elective management?

Answer 21

-Confirm viability, exclude significant malformation
-Ensure no infection
=Vaginal swab, MSU
-12-14 weeks (previous problems)
-Theatre
-GA or spinal
-Mersilene tape or monofilament suture
=Tocolysis?
=Antibiotics?

Question 22

Removal of sutures

Answer 22

-36-38 weeks planned
-Spontaneous Ruptured Membranes (clear liquor soaked pads, speculum)
=Delayed removal associate with increased neonatal mortality – sepsis
=Within 48 hours ( allow time for corticosteroids)
=CRP, temp, pulse etc
-Send to lab?
-At time of CS
-Shirodkar requires anaesthetic ( monofilament too)

Question 23

Describe transabdominal cerclage

Answer 23

-Strengthen the cervix at the level of the internal os
=previous failed (elective) vaginal cerclage: Look at this history in detail
=Trachelectomy (often sited at time of surgery)
=disrupted cervix
=absent cervix
-First described 1965- Benson and Durfee
-Laparoscopic modification in 1998
=High neonatal survival with both approaches

Question 24

Complications of open TAC

Answer 24

-Uterine injury
-Vessel injury
-Conversion to laparotomy- v rare
-Mid trimester IUD or SRM is challenging
-ELCS – often leave TAC in place
-Suture migration
=Rectovaginal fistual in years to come

Question 25

Testing for ruptured membranes

Answer 25

Amnisure
-PPV 94.6%
-ACOG – 19-30% false positive
-Importance of clinical picture
-Consider re-evaluating at a later point If negative + no amniotic fluid seen = advise + discharge with advice tore-presen

Question 26

Management of SRM

Answer 26

-HX exam
-Infection screen- HVS, MSU, FBC, CRP
-Erythromycin (never tocolysis)
-Scan for presentation
-Admit