L14 Obesity in Pregnancy Flashcards
What are the classifications of BMI ranges?
- Overweight if BMI over 25
- Preobese (25 - 29.99)
- Obese 30+ (class III/morbid if over 40)
- Supermorbid if over 50
What is the current prevalence of maternal obesity in the UK and elsewhere?
- 21% of antenatal population
- 47.3% of pregnant women have normal BMI
- 2% morbid obese, 0.2% supermorbid
- Prevalence of maternal obesity ranges from 1.8% to 25.3% across countries
How does obesity affect time in hospital during pregnancy and associated costs?
- Obese women on average spend 4.83 more days in hospital
- 5x increase in costs
List 4 basic causes for obesity:
- Energy intake greater than expenditure
- Influence of genetics and ill health
- Lack of physical activity
- Societal and psychological influences
How may genetics influence obesity?
- Certain genetic conditions can lead to obesity e.g. uncontrollable eating in Prader-Willi syndrome
- Note that there are no medical conditions which completely preclude weight loss
Give 2 conditions and 2 pharmaceuticals which may lead to weight gain:
- Hypothyroidism
- Cushing’s syndrome (excess cortisol)
- Corticosteroids
- Antipsychotics
List some general risks of obesity:
- T2DM, insulin resistance
- Hypertension
- Dyslipidemia
- Sleep apnea
- Anaesthetic risk
- Gallbladder disease
- CHD
- Osteoarthritis
- Cancer (colon, breast, endometrium)
- PCOS
What are the risks of obesity during pregnancy?
- GDM
- PE
- VTE
- Labour complications, high C-section rates
- Anaesthetic risk
- Higher risk of OH and infection
- Lower breastfeeding rates
What are 3 potential mechanisms for increased intrapartum risks in obesity?
- Fetal macrosomia -> disproportionate to pelvis
- Inta-abdominal and pelvic adipose tissue
- Dysfunctional uterine contractions
What is the relationship between BMI and C-section rates?
- Linear relationship between BMI at booking and risk of C-section
MBRRACE report: Obesity statistics in 2019 vs 2024
- Both reported a high proportion of maternal death in obese patients, particularly in VTE
- Proportion of deaths to obese mothers went up from 34% to 37%
How do obesity-related pregnancy complications impact long term health of mothers? (2 examples)
- Developing PE -> heightened risk of CVD in long term
- GDM -> 7x increased risk of developing T2DM (necessitates yearly screening)
What are the risks of maternal obesity to the fetus?
- Miscarriage, stillbirth, neonatal death
- Prematurity
- Congenital abnormalities e.g. spina bifida
- Macrosomia -> shoulder dystocia, brachial plexus injury
- FGR
- Hypoglycaemia
- Hyperbilirubinaemia -> Jaundice
- Respiratory distress syndrome
How can maternal obesity lead to hypoglycaemia in infants?
- High maternal blood sugar -> raised insulin production in utero
- Excess insulin in external environment -> failing to maintain blood sugar
Outline the Pederson’s hypothesis:
- Mechanism for macrosomia in mothers with diabetes
- Raised maternal glucose -> raised fetal glucose, raise insulin and increased growth
- Looking out for both amniotic fluid insulin levels and increased abdominal circumference in fetus
Consequence of shoulder dystocia:
- Manoeuvres required to get baby out put them at serious risk of brachial plexus injury
- Damage can be managed with physiotherapy but can sometimes be permanent
- Long term: weakness in arm/hand, decreased feeling
What are the health risks of maternal obesity for the child?
- Obesity
- Cardiovascular function (high BP)
- Increased diabetes risk
- Cognitive and behavioural disorders (ADHD, eating disorders, psychotic disorders)
What are some plausible mechanisms for the link between maternal and childhood obesity?
- Maternal obesity -> peripheral and hepatic insulin resistance
- Increase in metabolic fuels, glucose, lipids, leptins, AAs
- Inflammatory state with altered adipocyte function, increased adipocyte size
- Potential long term effect on fetus
- (Long term epigenetic modification of specific fetal genes ultimately leading to altered organ function)
What pre-pregnancy measures are taken to care for obese mothers?
- Weight loss in advance -> explaining benefits, dietician counselling (looking to reduce at least 5 - 10% weight to have benefits on outcome)
- Can also medically intervene (orlistat pancreatic lipase inhibitor with contraceptive advice, liralutide)
- Pre-conception vitamins (folic acid and vitamin D)
- Folic acid particularly important in reducing risk of spina bifida
- Referral to multidisciplinary clinic
- Bariatric surgery in some cases -> nutritional supplements before pregnancy, 18-month wait before conception)
How should obesity be managed during pregnancy?
- Dieting and significant weight loss not advised during pregnancy
- Instead, dietary advice and exercise support given mainly to prevent excessive weight gain in this period
- Continuing with folic acid support
- The role of the dietician is important in dispelling myths around pregnancy, nutrition and exercise
What screening takes place for maternal diabetes?
- All pregnant women with BMI over 30 at booking should be screened using oral glucose tolerance test
- Should take place at 24 - 28 weeks gestation
How is the risk of VTE managed in obese mothers?
- VTE assessment at first antenatal visit and throughout pregnancy
- Thromboprophylaxis may be considered (given to all women with BMI over 40) -> low molecular weight heparin
- Women with BMI over 30 encouraged to mobilise as early as they can after birth
How is the risk of preeclampsia managed in obese mothers?
- Risk assessed -> moderate risk factors include BMI>35, first pregnancy or first pregnancy in 10 years, age >40, family history of PE, multiple pregnancy
- If more than 1 moderate risk factor encountered, 150mg aspiring issued daily starting before 16 weeks of gestation
Why are anaesthetists often involved in advance of labour for obese mothers?
- Potential labour complications -> important to assess, plan and document in advance
- Issues include venous access, anaesthetic risks, specialist equipment (e.g. theatre table weight restrictions), specialist surgeon requirements
- Key issue is minimising time delays to give both patients best chances if things go wrong, since interventions will take longer in obese patients
How is fetal growth assessed in obese patients and why?
- Symphsiofundal heigh measurements becomes unreliable above a BMI of 35
- Will instead use serial USS for growth asessment (from 28 weeks if BMI>40 and from 32 weeks if BMI>35)
What intrapartum interventions are used when mothers BMI is over 40?
- Continuous electronic fetal monitoring
- Early IV access, FBC G&S
- Oral fluids only, consider IV fluids
- Omeprazole 20mg 12 hourly (stops aspiration of stomach contents into trachea under anaesthetic)
- Anaesthetist consulted in advance
- Consultant and birth location carefully considered
What special measures may be used during C-section of obese patients?
- Extra assistants
- Alexis retractor to protect incision site
- Negative pressure dressing (no longer evidence based)
- Prophylactic antibiotics
What is the recommended postnatal management in obese mothers?
- VTE risk assessment ongoing
- Antibiotic prophylaxis following C-Section
- Contraception advice
- Support with breastfeeding
What are the benefits of interpregnancy weight reduction in women with obesity?
- Significant reduction in risk of complications like…
- Hypertension
- GDM
- Fetal macrosomia
