Maternal Obesity the risks

1
Maternal Obesity the risks

• Dr Mark McLean
• Endocrinologist
• Blacktown Westmead Hospitals
• (with thanks to Dr Jennifer Bradford and A/Prof
  Leonie Callaway)

2
Overview

• Extent of the problem?
• Maternal Fetal risks
• What can we do about it?

3
Obesity in Australia

• In Australia 52 of women are overweight (BMI
  25-30) or obese (BMI gt30)
• 2.5 fold increase in 20 years
• Trend is rising fastest for young women(Ausdiab
  Study, Med J Aust 2005 178427)
• 41 women aged 18 to 23 gained weight between
  1996 and 2000 - average 2.5 kg
• If you had a baby - 5.4 kilograms. (Australian
  Longitudinal Study on Womens Health
  alswh.org.au)
• AUSTRALIAN PREGNANT WOMEN ARE NOW HEAVIER THAN
  EVER BEFORE

4
The risks

• Mother
• Hypertension
• Diabetes
• Thrombo-embolism
• Haemorrhage
• Death

• Baby
• Malformations
• Macrosomia
• Birth injury
• Perinatal death
• Later diabetes obesity

5
UK Confidential enquiry maternal deaths

• Depression and obesity are now the major
  causes of deaths related to pregnancy in UK.
• Obese women have roughly doubled risk of death.
  (BMJ  20043291205)

6
Maternal Complications - Diabetes

• Gestational Diabetes
• Obesity causes insulin resistance
• Increased inflammatory mediators
• Increasing risk with increasing maternal
  pre-pregnancy BMI
• Obese women OR 3.6 15.3
• Permanent Type 2 diabetes is now common in
  pregnancy, carries higher risk than Type
  1.(McElduff et at Diabetes Care 2005 281260)

7
Diabetes in Pregnancy at Blacktown

• - Increasing T2DM
• Increasing insulin usage
• Increasing complications

8
Maternal Complications - HT

• Hypertensive disorders of pregnancy
• Increasing maternal pre-pregnancy BMI is
  associated with
• Essential hypertension
• Gestational hypertension
• Pre eclampsia
• Independent of diabetes
• Systematic review
• Risk of pre eclampsia doubles for every 5-7 kg/m2
  increase in pre pregnancy BMI (OBrien et al,
  2003)

9
Maternal Complications - thrombosis

• Highest risk assoc. with C-section
• DVT4-fold increased risk (2.3 vs 0.6)(Edwards
  Obstet Gynecol, 1996, 87389)
• Pulmonary embolism in pregnancy
• Normal weight 0.04
• Overweight 0.07
• Obese 0.08 (Sebire et al, 2001)

10
Obstructive Sleep Apnoea

• Obese pregnant women are more likely to snore and
  tend to have sleep apnoea and hypopnoeas
  (Maasilta et al, 2001)
• This may be related to adverse fetal outcomes
  (Pien and Schwab, 2004)

11
Intra-partum complications

• Increased risk of induction of labour
• Higher rate of failed induction in obese
• Higher rate of failed vaginal birth after
  C-Section
• Dramatically increased rates of C-Section
• Increased rates of operative delivery
• Increased rates of complicated normal vaginal
  delivery
• Shoulder dystocia
• Third/fourth degree lacerations
• Failure to progress
• Mechanisms?
• Infant size, increased fat in the soft tissues of
  the pelvis, suboptimal uterine contractions

12
Anaesthetic complications

• Epidural analgesia during labour is more likely
  to fail as BMI increases (Dresner et al, 2006)
• General anaesthesia complicated by
• Postpartum sleep apnoea
• Difficult intubation
• More frequent aspiration(Hood, Anesthesiology
  1993 791210)

13
Perioperative complications

• Increased post-partum haemorrhage
• Endometritis
• Wound breakdown and infection
• Longer hospital stay
• Chest infection (RR 1.34)

14
Practical Difficulties

• Inaccurate assessment of growth, lie,
  presentation
• Blood pressure cuffs/automated blood pressure
  devices
• Vascular access
• Theatre beds/trolleys/staff
• Ultrasonography
• Monitoring during labour

15
Fetal assessment

• Ultrasonography in obese women is often
  suboptimal
• Fetal anomolies more likely to be missed
  (RR1.43)
• Clinical assessment of fetal size
  unreliable(Wolfe et al, 1990)

16
Fetal malformations

• Increasing BMI associated with
• Neural tube defects
• CNS defects
• Cardiac 2x
• Ventral wall -3x
• Intestinal defects
• Multiple defects
• Mechanism?
• Insulin, triglycerides, uric acid, estrogens,
  chronic hypoxia, hypercapnoea, fuel mediated
  teratogenesis, adequacy of folic acid, failed
  detection?

• Big worry folate doesnt protect the infant of
  obese women

17
Birthweight

• Macrosomia increased with
• Maternal pre-pregnancy BMI
• Weight gain during pregnancy
• Gestational diabetes
• Babies are getting bigger
• Catalano Term singletons have increased by 116g
  over 30 years
• Maternal pre pregnancy BMI is the most important
  predictor of fetal fat mass (Catalano et al,
  2003)
• LGA babies 4 times as many born to obese women,
  as to women with diabetes

18
Stillbirth

• OR antepartum and neonatal death in obese women
  2.0 3.4
• Mechanism
• Obese pregnant women have
• Impaired microvascular endothelial function
• Higher triglyceride levels
• Lower HDL levels
• Hyperinsulinemia
• Higher inflammatory markers (Ramsay et al, 2002)
• Sleep apnea has been related to poor fetal
  outcomes (Pien et al, 2004)

19
Stillbirth in Obese Women
(Nohr et al, Am J Obstet Gynecol 2005 106,
250-259)
20
In summary

• Anything that can go wrong in pregnancy is more
  likely to do so in obese women.
• This is not simply due to increased diabetes
• There are independent effects of- pre-pregnancy
  weight- additional weight gain in pregnancy-
  diabetes

21
Long term fetal outcomes

• Obese babies are NINE TIMES more likely to grow
  into obese adults (Baird et al, 2005)
• Higher birthweights are associated with
  adolescent obesity

22
Long term maternal outcomes

• Gestational weight gain is related to post partum
  weight retention
• Pregnancy provides a window to look at the
  womans metabolic future
• Type 2 diabetes
• HDP cardiovascular disease, stroke, MI,
  hypertension

23
What to do?

• Measure weight
• Talk to her about her weight, she is likely to be
  motivated
• Do not allow access to low-risk models of care
• Treat this as an opportunity for long-term
  behaviour modification
• Aim for limited weight gain in pregnancy

24
What is optimal weight gain?
Kiel et. al. 120,251 pregnancies, Missouri USA
(Obstet Gynecol, 2007, 110752) Cedergren. 300,00
0 pregnancies, Sweden (Obstet Gynecol 2007
110759)
25
Life Balance Program pilot intervention

• Recruitment in 2007
• BMI gt35, gestation lt 26 weeks
• Individual dietitian appointments and follow-up
• Food diaries and personal feedback
• Physical activity program, offered twice weekly
• 59 women involved, 35 completed program
• Average booking BMI 44
• Significant modification of diet, some increases
  in activity

Cost 16,000 for 1 year
26
Comparison of 2 pregnancies booking BMI
Average 42
Average 38
This pregnancy
Last pregnancy
27
Comparison of 2 pregnancies weight gain
Average 16kg
Average 8kg
Last pregnancy
This pregnancy
28
Summary

• Maternal obesity is associated with significant
  risk to mother and baby
• It is a modifiable risk factor
• Pro-active approach is justified
• Likely to be cost-effective
• Most efficacious interventions not yet determined

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