Fetal and Maternal MedicineRCOG Part 2 MRCOG Course

Dr Janet R Ashworth

Consultant in Fetal and Maternal Medicine

Royal Derby HospitalConflicting interests: none.

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Aim of session

• To cover some of the current and some poorly but commonly-managed areas of high risk pregnancy.

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Subjects

• Complex multiple pregnancy• Pre-term labour and delivery• Red cell antibodies.

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Complex Multiple Pregnancy

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Complex Multiple Pregnancy

• Monochorionic Twins

• Higher multiples

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General points for all multiple pregnancies

-NICE guidance, 2011-11-14 weeks, dating, Down’s screen (prn), determine chorionicity and determine identifiers for fetuses.-Core teamRisks: -Miscarriage -Stillbirth(1 -0.5%; 2-1.2%; 3-3.1%)

-Anaemia -Maternal mortality x2.5-Hypertensive disorders-APH/PPH -Congenital anomaly x5-Operative delivery -IUGR (aspirin)-Preterm delivery (60%; 10%<32/40)

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Monozygotic Twins; additional risks

• DCDA (1/3 of MZ twins. Will be same sex!)• MCDA: Discordant growth; TTTS; TAPS; Demise of co-twin effects.• MCMA: Cord entanglement; TRAP syndrome.• Conjoined Twins: Co-dependence risk; separation risk.

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Fetal Medicine Centre Role

• Triplet pregnancies with one or more monochorionic element• Monoamniotic twinning• Discordant growth or death• Fetal anomaly• TTTS/TAPS.

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Delivery in Uncomplicated Multiple Pregnancies

• DCDA 37-38 weeks• MCDA 36-37 weeks, with steroids• Triplets 35-36 weeks, with steroids• MCMA by 34 weeks, with steroids.

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Red Cell Alloimmunisation

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Problems with red cell antibodies

• Fetal anaemia, haemolytic disease of the newborn (HDN), crossmatching problems

• HDN and x-matching problems• X-matching only.

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Red Cell Alloimmunisation

• Fetal anaemia

• Rhesus D• Rhesus c• Kell• Anti-G• (Duffy a)

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Rhesus (D) Disease

• Anti-D antibodies (Rhesus negative mother)- Now less common problem since prophylactic anti-D.- Rhesus disease typically increases in severity with serial Rhesus positive

fetuses.- Next fetus may be affected up to 10 weeks earlier in gestation than last.- Anti-D titres above 4 iu/ml suggest risk.- Low titres only reassuring in 1st affected pregnancy.

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The Other Red Cell Antibodies Causing FetalAnaemia

• Anti-c, Anti-Kell- May cause fetal anaemia in first pregnancy where alloimmunisation

identified.- Anti-Kell causes profound early-onset fetal anaemia by affecting red cell

progenitors. - Kell alloimmunisation usually transfusion-acquired. Shouldn’t occur any more!

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The Changing Role of Ultrasound in Managing Rhesus Disease …..• The development of non-invasive monitoring for fetal anaemia. • Mari et al Ultrasound Obstet Gynecol 1995; 5: 400-5. N Eng J Med

2000; 342: 9-14.1.

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Middle Cerebral Artery on USS

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Measuring MCA PSV

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Using MCA PSV in Rhesus Disease

• Has been shown to better predict fetal anaemia than serial amniocentesis and delta OD 450. Oepkes et al N Eng J Med 2006; 355: 156-64.

• High sensitivity and low false positive rate• Now used in monitoring post-intrauterine transfusion.

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Monitoring Fetuses at Risk of Fetal Anaemia due to Rhesus Disease.

• Significant maternal anti-D levels (>4iu/ml) or previously affected fetus.• Fetal genotype• If fetus Rhesus D positive, monitor MCA PSV from 10 weeks prior to

previous gestation at which affected.• If first pregnancy with alloimmunisation, monitor MCA PSV weekly from

16 weeks. Increase surveillance if rising anti-D titres.• Severely affected previous fetus – consider IVIg to delay serial

transfusion.

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Monitoring in c/Kell Alloimmunisation

Fetal genotyping (most people are Kell-negative!).• Weekly monitoring from 16-18 weeks (or when anti-c titre > 7.5

iu/ml).• Management as for anti-D alloimmunisation once anaemia suspected.• May need intra-peritoneal transfusion or to consider ivIg infusions.

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• Fetal blood sampling and intravascular transfusion

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Outcome of IUT in Rhesus Disease

• 95% survival with intravascular IUT.• 70-80% if hydropic.• Median number of transfusions 3.• Mean Hb at transfusion 7.7g/dl.• Mean gestation at delivery 34 weeks.• Managed by caesarean delivery 34-36 weeks.• Serial IUT inhibits fetal haematopoiesis; top-up neonatal transfusions

likely.

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Red Cell Alloimmunisation• Haemolytic Disease of the Newborn (anaemia with jaundice, risk of

kernicterus)Rhesus C, E, e

Duffy (Fya)

Kidd (Jka (Jkb)M, S, s

• Neonatal liaison. Cord bloods (DAT, group and bilirubin)

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Pre-term Delivery

• Prophylaxis• Diagnosing PPROM• Diagnosis and treatment of PTL• Steroids• Magnesium sulphate• Delivery

NICE guidance 2015

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Preventing Preterm delivery

Vaginal progestogen OR elective cerclage-Previous delivery 16-34 weeks + cervical length 16-24wk <25mm

Vaginal progestogen-no Hx prematurity but cervix <25mm 16-24wk

Cerclage-previous PPROM or cervical trauma and <25mm 16-24wk

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Pre-term premature rupture of membranes

• Diagnosis:

• Liquor seen on speculum• No liquor seen but positive specific test (ILGF binding pr-1 or

placental alpha-macroglobulin-1. NOT nitrazine); if history supportive then treat as PPROM. Diagnostic test not indicated if in established labour.

• Diagnosis of infection requires CRP, WBC, fetal HR. Single marker unreliable.

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Diagnosing Pre-term Labour

• Clinical history• Speculum with digital VE if cervix not clearly seen• If <30 weeks, treat as pre-term labour• If>30 weeks use TV USS <15mm or fFN>50ng/ml if available to

confirm high risk of delivery in <48 hours. Negative tests allow reassurance.

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Management of Pre-term Labour

• Rescue cerclage considered if 16-27wk, dilated cervix and no PPROM, no infection, no bleeding and no contractions.

• Consider tocolysis (nifedipine if not contra-indicated, oxytocin receptor antagonist otherwise) if 24-26 weeks and suspected PTL, or >26 weeks and diagnosed PTL.

• + considering in-utero transfer• - bleeding, infection.

• Steroids prior to 36 weeks

• MgSO4 for fetal neuroprotection if 24-30wks(consider up to 34wk).

• Consider caesarean for breech 26-37 weeks. Otherwise no advantage just for prematurity.

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Maternal Medicine – Recent Information

• MBRACE• UKOSS• National Perinatal Cardiology Review• Green-top guidelines:• Thalassaemia• Thrombosis• AIP (abnormally invasive placenta) pathways; praevia guideline.

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Questions?

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