46 weeks of care – 46 weeks of care – sharing the patient journey through sharing the patient journey through pregnancy to 6 weeks post-partumpregnancy to 6 weeks post-partum

3rd November 20123rd November 2012CHWCCHWC

The Canberra HospitalThe Canberra Hospital

Management of ObesityManagement of Obesityin pregnancyin pregnancy

Steven AdairClinical Director O&G

CHWC, Canberra

DefinitionsDefinitions

• BMI is the most commonly used indicator of maternal weight (wt in kg/height in m2 )

• The usual categories are;– BMI 18.5 to 25 is normal weight range– BMI > 25 is overweight– BMI > 30 is obese– BMI > 35 is severe obesity– BMI > 40 is morbid obesity– BMI > 50 is extreme morbid obesity

DemographicsDemographics

• One and a half billion adults worldwide are overweight, and half a billion are obese

• Australia now has one of the highest rates of overweight and obesity in the world

• Latest figures show that 21.7% of the population is obese (60% are overweight)

• One in fourOne in four Australian women are obese

BMI: 71.8BMI: 71.8

Extreme Morbid ObesityExtreme Morbid Obesity

AMOSS conditions 2010-2011AMOSS conditions 2010-2011

• Antenatal pulmonary embolism• Amniotic fluid embolism• Eclampsia• Extreme morbid obesity (BMI >50)• Influenza A with admission to ICU• Peripartum hysterectomy• Placenta accreta

AMOSS surveillance 2010–2011AMOSS surveillance 2010–2011

2010–2011 conditions Number of cases

Rate/1000 births

a95% CI Maternal deaths

% case fatality

Morbid obesity BMI>50 370 2.68 2.49, 2.87 0 -

Influenza A ICU admission 36 0.19 0.14, 0.28 0 -

Amniotic fluid embolism 36 0.04 0.03, 0.06 5 14

Antenatal pulmonary embolism 104 0.12 0.10, 0.14 0 -

Eclampsia 135 0.22 0.18, 0.26 0 -

Placenta accreta 285 0.42 0.38, 0.48 2 1

Peripartum hysterectomy 399 0.60 0.55, 0.65 3 1

AMOSS SurveillanceAMOSS Surveillance

• Data collection was suspended after 10 months due to data overload

• 357 cases reported from > 170,000 births (approximately 2 per 1000)

• 179 (53.7%) had a c/section– Elective c/section 94 (53%)– Emergency c/section 85 (47%)

BMI in pregnancyBMI in pregnancy

• Pre-pregnancy BMI is not routinely collected (studies use maternal recall)

• End of pregnancy BMI is altered by weight gain in pregnancy

• BMI at booking visit (often 12 to 20 wks) is accessible data

2011 figures from The Canberra Hospital2011 figures from The Canberra Hospital

• Many units in the Canberra region will transfer women with BMI > 35 for birth– In 2011 (2577 / 2805)

• BMI > 30 in 515 20% (43 per month)• BMI > 35 in 230 9% (20 per month)• BMI > 45 in 28 1% (>2 per month)

• This means that each week there are 2 or 3 women birthing with morbid obesity

Recent EvidenceRecent EvidenceOctober 2012October 2012

• Editorial:

“The increasing impact of maternal obesity on obstetric practice.”

• Pre-pregnancy BMI• Intra-pregnancy weight gain

• IOM guidelines for weight gain in 1st T of <1.5kg in obese.

Pregnancy ConsequencesPregnancy Consequences

• Congenital anomalies• Diabetes• Stillbirth

Congenital AnomaliesCongenital Anomalies

• The data showing an increased risk of congenital anomalies are inconsistent

• Possible explanations include;– Relative folate deficiency– Higher rates of undiagnosed type 2 DM– Later diagnosis of severe anomalies may increase

birth prevalence

Gestational DiabetesGestational Diabetes

• Clear association between BMI and risk of GDM

• Women with BMI > 40 have a 10% risk

• Strongly linked to need for insulin, fetal macrosomia and c/s 0

1

2

3

4

5

6

7

8

9

10

<18.5 >25 >35GDM%

aOR

StillbirthStillbirth

• Maternal overweight & obesity are very significant modifiable risk factors for stillbirth

• The top PARs (Population Attributable Risk) for stillbirth at >22 weeks in HIC are;– Overweight/obesity (7.7 to 17.6%)– Maternal age (7.5 to 11.1%)– Smoking (3.9 to 6.2%)

Flenady et al (2011), Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis Lancet 377, 1331-1340

Association of overweight and obesity with Association of overweight and obesity with stillbirth in High Income Countries (HIC)stillbirth in High Income Countries (HIC)

Flenady et al (2011), Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis Lancet 377, 1331-1340

Birth ConsequencesBirth Consequences

• Timing of birth?• Place of birth?• Mode of birth?

Place of birthPlace of birth

• Many low-risk units will preferentially transfer women with BMI > 35– Anaesthetic risks– Surgical risks

• This policy causes much maternal distress and family dislocation

• Possible to triage based on fetal size and previous obstetric history

Mode of birthMode of birth

• All studies show higher c/section rates in obese women

• Why is this so?– Bigger babies– Less efficient uterine activity– More iatrogenic intervention?

Birth outcomes TCH 2011Birth outcomes TCH 2011

Caesarean Section Rate (26.1%)

BMI >35 40.43%

BMI >45 42.85%

Implications for Maternity ServicesImplications for Maternity Services

• Increased workload in relation to GDM• Special clinics/models of care for women with

high BMI– Dietitian/psychologist/physiotherapist

• Protocols for managing surgical and anaesthetic risks for women with BMI > 50

• Need for transfer for women deemed to be at higher risk

Clinical Practice Guidelines

Antenatal Care – Module 1

Draft for AHMAC

February 2012

Clinical Practice GuidelinesAntenatal Care – Module 1

Draft for AHMACFebruary 2012

7.2 Weight and body mass index

7.27.2 Weight and body mass indexWeight and body mass index

• ‘‘Pre-pregnancy weight and weight gain during Pre-pregnancy weight and weight gain during pregnancy are important determinants of both pregnancy are important determinants of both mother and baby.’mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, positive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

7.27.2 Weight and body mass indexWeight and body mass index

• ‘Pre-pregnancy weight and weight gain during pregnancy are important determinants of both mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, positive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

7.27.2 Weight and body mass indexWeight and body mass index

• ‘Pre-pregnancy weight and weight gain during pregnancy are important determinants of both mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, positive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

7.27.2 Weight and body mass indexWeight and body mass index

• ‘Pre-pregnancy weight and weight gain during pregnancy are important determinants of both mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, positive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

7.27.2 Weight and body mass indexWeight and body mass index

• ‘Pre-pregnancy weight and weight gain during pregnancy are important determinants of both mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, positive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

7.27.2 Weight and body mass indexWeight and body mass index

• ‘Pre-pregnancy weight and weight gain during pregnancy are important determinants of both mother and baby.’

• Measure women’s weight and height at the first antenatal visit and calculate their BMI. (B)

• Repeated weighting during pregnancy should be confined to circumstances that are likely to influence clinical management. (pp)

• Give women advice about appropriate weight gain during pregnancy in relation to their BMI. (B)

• Taking a respectful, postiive and supportive approach and providing information about healthy eating and physical activity in an appropriate format may assist discussion of weight management. (pp)

Possible interventions

• Pre-pregnancy counselling– many pregnancies are unplanned– sub-fertility in overweight/obese women– assisted reproduction technology (ART)

• Reducing weight gain in pregnancy– dietician involvement and routine weighing

• Maximising inter-pregnancy weight loss– breastfeeding

Possible birth interventionsPossible birth interventions

• There are a number of ‘birth choices’ for overweight and obese women that are yet to be properly trialled– Early v standard timing of birth– Spontaneous v induced labour– Emergency v elective caesarean section?

Timing of birthTiming of birth

• There is pressure to intervene due to the increased risk of stillbirth, and GDM

• Does more intervention lead to greater complications?

• How should standard IOL policies be modified by maternal BMI?

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Placental Responses to Obesity and Pregnancy Outcomes Study

PROPOSPrincipal Investigators-

Prof Christopher Nolan Prof Jane DahlstromProf David Ellwood A/Prof Alison Kent

PROPOS

• The PROPOS study will evaluate the effects of obesity on placental structure and function and how this affects pregnancy outcomes

PROPOSFor the women it involves-•Recruitment if eligible prior to 12 weeks gestation•4 weekly visits to TCH from 12 weeks gestation•Dietary and exercise advice•Fetal Medicine Unit ultrasound assessments at 12, 20, 28 and 36 weeks gestation•Maternal anthropometric/ metabolic assessments at 16, 24, 32 weeks gestation•Maternal and cord blood taken at delivery•Detailed study of placenta (appearance, histology, metabolism, gene expression)•Neonatal anthropometric/ metabolic assessment and review at 12 months•All maternal and fetal/neonatal adverse outcomes will be carefully documented

PROPOS

38

HyperglycaemiaHyperglycaemiaDyslipidaemiaDyslipidaemia

InflammationInflammation

Maternal

obesityAbnormal adipokinesAbnormal adipokines

Beneficial placental adaptations

Beneficial placental adaptations

Harmful placental adaptations

Harmful placental adaptations

Altered placental function

and/or structure

Altered placental function

and/or structure

Systemic HypertensionSystemic Hypertension

Other factorsOther factors

PROPOSSelection Criteria for PROPOS Subjects

Inclusion criteria study B:•Age 20-38•<12 weeks gestation•Nulliparous•Obese BMI 30.0

Inclusion criteria study A:•Age 20-38•<12 weeks gestation•Previous C-section•Lean BMI 18.5-25.0•Obese BMI 30.0

Exclusion Criteria:•Pre-existing diabetes, chronic hypertension, active smokers, delivering at hospital other than TCH, induced conception

For further information or patient referral, please contact: Endocrinology Unit, The Canberra Hospital on 6244 2228 or Anthea Oon, Research Coordinator, Clinical Trials Unit 6244 3687

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