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OG Perinatal UpdateSaturday, 10 November 2007
Dr Rahul Sen, BA, MBBS, FRANZCOG, DTMH, Grad Dip
Ec. Visiting Medical Officer, Royal Hospital for
Women and Prince of Wales Private Hospital,
Randwick
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Gestational Diabetes Mellitus (GDM)

• Are the risks the same as pre-existing diabetes?
• Recent studies
• How to monitor/assess macrosomia?
• When to deliver?
• Who should look after?

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Gestational Diabetes

• Carbohydrate intolerance of variable severity
  with onset or first recognition during pregnancy
• i.e. includes previously unrecognised type 2
  diabetics
• 5-7 of all pregnancies

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Gestational Diabetes

• Are the fetal risks the same as pre-existing
  diabetes?
• - congenital malformations (x3) HbA1C
• - early pregnancy loss
• - SGA
• - preterm labour (x4)
• - macrosomia (x6)
• - stillbirths
• - neonatal hypoglycaemia
• - adult diabetes 50 within 10 years  ie
  potential for lifestyle modification

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Recent Studies

• ACHOIS
• - Crowther et al, NEJM 352(24)2477-86, June
  2005
• - RCT to determine whether treatment of GDM
  reduced risk of perinatal complications
• - Showed significant reduction (1 vs 4) in
  serious perinatal complications in treated GDM
• - Showed improved quality of life in treated group

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Fetal Macrosomia

• Increased risk of dystocia, especially in
  second stage
• Increased risk of shoulder dystocia (ACHOIS)
• Increased risk of brachial plexus injury
• Increased perinatal mortality
• Increased maternal morbidity

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Assessing Fetal Macrosomia

• - Clinical judgement unreliable
• - Ultrasound /- 15
• - More than just EFW
• AC 35 cm predictive of macrosomia (Jazayer et
  al, AJOG 93(4)523-7, 1999 and Henrichs et al, J
  Reprod Med 48(5)339-42, 2003.)
• RHW
• Growth scan at 36 weeks (diet)
• Growth scan at 32 36 weeks (insulin)

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Fetal Macrosomia

• Review Article by Kjell Haram, ACTA Scandinavia
  2002 18(3)185-200
• No benefit of induction in non-diabetic
  macrosomia
• Macrosomia occurs in 25-50 of diabetic
  pregnancies
• Approximately 10 of diabetic pregnancies have
  shoulder dystocia
• Selected diabetic women with suspected macrosomia
  should be offered induction or caesarean section
• 50 shoulder dystocia occurs lt4000g.
• 50 occur without warning, although often slow
  progress in first or especially second stage, and
  assisted mid-cavity delivery

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When to deliver?

• Cochrane Review One RCT only (Kjos et al, 1993
  AJOG)
• - Reduction in macrosomia with induction 38
  weeks
• - No change in caesarean section rate
• - Numbers too small to detect reduction in
  mortality
• Lurie (AJPerinatol, 1996)
• - Induction at 38-39 weeks reduced shoulder
  dystocia with no increase in caesarean rates
• RHW
• - GDM on high dose insulin/macrosomia 38 weeks
• - GDM on low dose insulin, no macrosomia 39
  weeks
• - GDM on diet control, no macrosomia 40 weeks

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When to deliver?

• Falling insulin requirements at term
• Macrosomia EFW 4000g /- AC 35cm
• ? Polyhydramnios
• Options close monitoring /- delivery
• Complicating factors
• - Obesity
• - Ethnicity
• - Parity

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How to deliver?

• Expectant management
• Induction of Labour
• Elective Caesarean
• Many studies Sanchez-Ramos, Ecker, Sacks,
  Simhayoff, Kjos, Hod, Lurie, Horrigan
• RHW
• - Discuss caesarean if EFW gt 4000g or if AC gt
  35cm
• - Recommend IOL to all others

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Who should look after?

• All pre-existing diabetics joint
  obstetric-diabetic clinic
• Gestational diabetics on insulin joint
  obstetric-diabetic clinic
• Diet controlled GDM
• - Too many for joint clinic
• - Doctors clinic/ share care
• - ? Low risk models of care

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Consensus Recommendations

• Cochrane
• Inadequate evidence for review of GDM (prior to
  ACHOIS)
• Insufficient data for recommendation on IGT
• RANZCOG
• GDM universal screening with 50g GCT with 1
  hour BSL of gt7.8 then 75g OGTT with fasting BSL
  gt5.5 or 2 hour BSL gt8.0
• Delivery at term, neonatal monitoring and GTT 6
  weeks post partum then 2 yearly

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Recommendations

• ADA
• GDM delivery during the 38th week
• ACOG
• No proven benefit in prophylactic C/S for
  suspected macrosomia but may be considered if EFW
  gt4500g in diabetic
• High Risk Pregnancy (2006)
• Conflicting evidence for 38-40 weeks

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Future Studies

• HAPO
• - 5 year observational study of 25,000 women
• - Outcomes macrosomia, C/S, morbidity,
  mortality, diabetes
• - Completed mid 2007 but not likely to be
  published until mid 2008
• - EXCLUDED diabetics and gestational diabetics
• - Preliminary data show highest septiles have
  worst outcomes

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Future Studies

• MIG
• - Study of 2,000 women with gestational diabetics
  randomised to Metformin or Insulin
• - Outcomes macrosomia, C/S, morbidity,
  mortality, diabetes, hypoglyaemia
• - Completed mid 2007 but not likely to be
  published until early 2008
• - Preliminary data show 50 of Metformin group
  required insulin as well
• No difference in any outcomes
• No long term safety data

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Summary

• Pre-existing diabetes
• Pre-conceptual counselling tight control
• Aim for HbA1C under 7.
• Add Folate 5mg for first trimester
• Book in early and manage in joint care unit
• Tertiary level morphology scan
• Fetal echo at 22-26 weeks
• Serial growth scans 2 weekly for type 1, 4 weekly
  for type 2
• Stimulation of lactation from 36 weeks
• Deliver 38 weeks. Consider C/S if EFW gt 4kg or
  AC gt 35 cm

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Summary

• Gestational diabetes
• Must be considered a clinical entity
• Controversy over screening, diagnosis, and
  management
• Few protocols but most deliver 38-40 weeks
• Post-partum screening is required in most cases
  to exclude latent type II DM, as 50 will develop
  DM within 10 years
• See Fraser, R. Diabetic Medicine 23 Supp 18-11,
  2006 for good summary of current situation

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Growth Assessment in the Non-Diabetic

• Dating scan
• Normal growth
• LGA and Macrosomia
• SGA and IUGR
• How to monitor
• When to deliver

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Growth Assessment in the Non-Diabetic

• Dating scan
• Benefits many women ? Most
• Cost-effectiveness unproven, especially with FTS
• Ideally 810 weeks
• Detects most early pregnancy loss
• Accurate to within 3 days in good hands
• Only change EDC if significant difference between
  LMP date and scan date

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Growth Assessment in the Non-Diabetic Normal
Growth
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Growth Assessment in the Non-Diabetic Normal
Growth
From Roberts, 1999
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Growth Assessment in the Non-Diabetic

• LGA and Macrosomia Definition
• Imprecise terms, no consensus (clinical vs U/S)
• Major hazard is shoulder dystocia and birth
  trauma
• Concern is SFH gt2cm more than gestation or gt41 cm
  at any stage
• Growth scan in recognised unit remember scan is
  /- 15
• LGA gt90th centile
• Macrosomia gt4000g /- other features

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Growth Assessment in the Non-Diabetic

• LGA and Macrosomia Management
• Major issues timing and mode of delivery
• Offer LSCS if gt 4500g
• Discuss IOL and LSCS if 4000-4500g
• No evidence for benefit of IOL for non-diabetic
  with suspected macrosomia
• IOL risks include worse labour, esp primigravidae
• Common practice IOL when Cx favourable at term

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Growth Assessment in the Non-Diabetic

• SGA and IUGR Definition
• Clinical vs U/S finding
• Main fetal weight gain 30-38 weeks
• SFH in cm approx gestational age in weeks
• Refer for scan if
• SFH more than 2cm less than gestational age
• OR
• no increase in fundal height in 2 weeks

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Growth Assessment in the Non-Diabetic

• SGA and IUGR Risks
• Major hazard is stillbirth
• x4 if lt10th centile
• x8 if 3rd-10th centile
• x20 if lt3rd centile
• High risk fetal distress in labour
• Risk of birth hypoxia and complications of
  prematurity
• Risks of metabolic/cardiovascular disorders in
  later life (Barker Hypothesis)
• Possible behavioural/psychiatric concerns

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Growth Assessment in the Non-Diabetic Risk
Factors

• Fetal factors
• Aneuploidy
• Genetic syndromes
• Congenital infections
• Maternal factors
• Low pre-pregnancy weight
• Cigarette smoking
• Substance abuse
• Severe anaemia
• Maternal hypoxia
• Previous growth restricted baby
• Recurrent miscarriage

• Maternal disease affecting placental vasculature
• Preeclampsia
• Autoimmune disease
• Thrombophilia
• Renal disease
• Diabetes
• Essential hypertension
• Other Placental factors
• Chronic abruption
• Uterine anomalies
• Placental infarction

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Growth Assessment in the Non-Diabetic

• SGA and IUGR Assessment
• U/S scan in recognised unit
• Management
• Serial growth scan every two weeks
• AFI and UA Doppler at least weekly
• Check MCA resistance if abnormal cord Dopplers
• CTG monitoring at least twice weekly

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Growth Assessment in the Non-Diabetic

• SGA and IUGR Delivery
• Deliver around 37-38 weeks depending on scenario
• earlier if no growth or decreased MCA resistance
• Immediately if non-reassuring CTG
• Usually recommend IOL, esp if multip Prostin or
  Foleys
• Caesarean if premature or severe IUGR

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Growth Assessment in the Non-Diabetic

• Summary of Macrosomia and IUGR
• Dating scan helpful
• Growth scan if greater than 2 cm difference
  between observed and expected SFH
• Monitor with serial scans and CTG
• Aim for delivery at term
• IOL if favourable and baby reasonable size
• Consider C/S if severe IUGR or macrosomia

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Questions?