Obs&gyn: Obesity Flashcards
How to calculate BMI?
Body Mass Index (BMI)
Weight (kg)/ Height2 (m2)
BMI ranges
- BMI of 25-30: Overweight
- BMI 30-34.9: Class 1 Obesity
- BMI 35-39.9: Class 2 Obesity
- BMI 40+: Class 3 or Morbid Obesity
How does obesity may cause a disease?
White fat around viscera sets up inflammation and cell death and causes disease
What’s Leptin?
Leptin
- produced by adipose tissue
- mediates long term appetite controls
- encourage us to eat more when fat stores are low, and less when storage is high
What’s Ghrelin?
Ghrelin
- produced by the empty stomach
- modulating short term appetite
- encouraging us to eat when the stomach is empty, and stop when the stomach is stretched
By use of what pathways leptin and ghrelin produce their effects on appetite?
- Leptin and ghrelin control the appetite through action on the central nervous system
- Act on the paraventricular and arcuate nuclei of the hypothalamus through several pathways
What (3) hormones adipose cells produce?
- Adiponectin → regulates fatty acid and glucose metabolism - levels are lower in obesity, which is related to insulin resistance
- Oestrogen
- Leptin - note levels of leptin are higher, but obesity leads to Leptin resistance
Complications of obesity
What BMI of >30 in pregnancy increases the risk of?
- Thrombosis
- Gestational Diabetes - 3 fold increase
- Pre-eclampsia - with BMI of 35 the risk is double that of a woman with a BMI of 25
- Neural tube defect
- Miscarriage - increases from 20% to 25%
- Increased birth weight - chances of a baby weighing more than 4kg are increased from 7% to 14%
- Stillbirth - risk increased from 1 in 200 to 1 in 100
- Increased risk of baby developing obesity or diabetes in later life
Risks of BMI >40 in pregnancy and labour
With a BMI of more than 40:
- Increased risk of prematurity
- Labour dystocia
- Shoulder dystocia
- Emergency caesarean section
- Intraoperative complications, including bleeding
- Postoperative complications, including wound infection
- Anaesthetic complications, particularly with general anaesthesia
- Postpartum haemorrhage
What advice to give for a woman of BMI of 30 or more wants to conceive?
- advice on weight and lifestyle should be given to all women of childbearing age
- support to lose weight prior to conception for all women with a BMI of 30 or more
- BMI of 30 or more should be advised to commence 5mg Folic Acid supplementation at least a month before conception and continuing during the first trimester of pregnancy
• BMI of 30 or more should be advised to commence 10 micrograms Vitamin D supplementation daily throughout pregnancy and while breastfeeding
Do we need to refer a pregnant obese woman?
Women with a BMI of 30 or more should be referred to a consultant obstetrician
When during pregnancy should we measure maternal weight and height?
- Weight and height should be measured and BMI recorded at booking visit
- Re-measurement of maternal weight in the third trimester will aid planning with regard to equipment and personnel
Considerations for maternal BMI >35 and pre-eclampsia
Women with a BMI of 35 or more have an increased risk of pre-eclampsia.
Assess additional risk factors and commence low dose aspirin
When and for whom do we do OGTT in pregnancy?
Women with a BMI of 30 or more should have a 2 hour 75g oral glucose tolerance test at 24-28 weeks
The anaesthetic risk for women with BMI 40 or more
Women with a BMI of 40 and above should have an antenatal consultation with an obstetric anaesthetist to assess and discuss potential risks with IV access and regional and general anaesthesia
- Epidural re-site and failure rates higher
- Higher risk of gastric content aspiration, difficult intubation and postoperative atelectasis with general anaesthesia
- Increased comorbidities including IHD and hypertension