Disorders in pregnancy Flashcards
What is the physiology of gestational diabetes?
• Glucose tolerance decreases in pregnancy due to altered carbohydrate metabolism and the antagonistic effects of human placental lactogen, progesterone and cortisol
women without diabetes, but with impaired or potentially impaired glucose
tolerance often ‘deteriorate’ enough to be classified as diabetic in pregnancy
• The kidneys of non-pregnant women start to excrete glucose at a threshold level of 11mmol/L- in pregnancy, this varies more but often decreases, so glycosuria may occur at physiological blood glucose concentrations- so urinalysis for glycosuria is not a useful diagnostic test
• Raised foetal blood glucose levels induce foetal hyperinsulinaemia, causing foetal fat deposition and excessive growth (macrosomia)
What are the definitions of diabetes in pregnancy?
Pre-existing diabetes: in those on insulin, increasing amounts will be required in these pregnancies to maintain normoglycaemia
Gestational Diabetes: ‘carbohydrate intolerance’ which is diagnosed in pregnancy, which may or may not resolves after pregnancy
How is gestational diabetes diagnosed?
fasting glucose level ≥5.6mmol?l or >7.8mmol 2hrs after a 75g glucose load (GGT) to diagnose gestational diabetes, depending on criteria used, up to 16% of pregnant women will develop gestational diabetes
What are the foetal complications of gestational diabetes?
• Congenital abnormalities (particularly NTD)- 3-4 times more common in women with established diabetes and are related to periconceptual glucose control
Preterm labour
Reduced foetal lung maturity
Birthweight increased (increased urine and polyhydraminos)
Dystocia and birth trauma
What are the maternal complications of gestational diabetes?
Insulin requirements increase (up to 300%)
Ketoacidosis (hypoglycaemia
UTI
• Wound or endometrial infection- after delivery are more common
• Hypertension & pre-eclampsia- more common
• Pre-exisiting ischaemic heart disease- often worsens
• C-section or instrumental delivery
• Diabetic nephropathy (5-10%)
• Diabetic retinopathy
What is the preconceptual care for diabetes in pregnancy?
o Glucose levels need to be optimum at conception to reduce risk of foetal complications- HbA1c should be <6.5% and pregnancy not advised is >10%. fasting glucose levels should be 4-7mmol/L
Metformin and insulin are fine other hypoglycaemia agents need to be stopped
o 5mg of folic acid will be given
o Statins stopped and anti-hypertensives (labetalol/methyldopa) given instead
o Renal function (creatinine <120µmol/L), BP and retinae are assessed
What is the management for diabetes in pregnancy?
• During pregnancy the aim for a fasting level of <5.3mmol/L and 1hr level <7.8mmol/L
• The renal function should be checked and the retinae screening for retinopathy
• Aspirin (75mg) daily from 12 weeks is advised to reduce the risk of pre-eclampsia
o Foetal echocardiography is indicted
o USS to monitor growth and liquor volume at 32 & 36 weeks
When is delivery advised in diabetes in pregnancy?
37-39 weeks is advised
Birth trauma more likely
C-section is used where estimated foetal weight is >4kg
during labour, glucose levels are maintained with a ‘sliding scale’ of insulin and dextrose infusion
• The neonate commonly develops hypoglycaemia as it has become accustom to hyperglycaemia and therefore has high insulin levels- levels should be checked within 4hrs, breastfeeding is strongly advised
What are the risk factors for gestational diabetes?
o Previous large baby (>4.5kg) o Unexplained stillbirth o 1st degree relative with diabetes o BMI >30kg/m2 o Minority ethnic family origin o Previous gestational diabetes
What screening is done for gestational diabetes?
- Screening using pre-existing risk factors, these women are given a GTT at 24-28 weeks
- HbA1c levels are checked to identify pre-existing diabetes, target levels are the same as in pre-existing diabetes
How is gestational diabetes managed?
• Initially managed with diet and exercise advise
if not maintaining glucose control then metformin and/or insulin is added
• Women should be managed as for pre-existing diabetes, however, well controlled gestational diabetes do not need to deliver before 41 weeks
Treatment should be discontinued postnatally, but fasting glucose should be measured at 6 weeks postnatal due to increased risk of T2DM- more than 50% will become diabetic within the next 10 years
What are the changes to the cardiovascular system during pregnancy?
there is a 40% increase in cardiac output
due to increase in stroke volume and heart rate and a 40% increase in blood volume
There is also a 50% decrease in systemic vascular resistance, so BP often drops in 2nd trimester but has returned to normal by term
• The increased blood flow produces a flow (ejection systolic) murmur in 90% of women
ECG is also altered during pregnancy and shows left axis shift and inverted T waves
How does increased CO during pregnancy affect the mother?
acts as an ‘exercise test’ with which the heart may be unable to cope
usually manifests
>28 weeks or soon after labour with decompensation in association with blood loss and fluid overload
Fluid overload can also occur in early puerperium as the uterine involution squeezes a large fluid load into the circulation
What are the types of cardiac disease during pregnancy?
Pulmonary hypertension: termination offered (20% mortality of mum)
• Cyanotic heart disease without pulmonary hypertension: (anti-coag offered)
Aortic stenosis: (bb used, epidural analgesia is contraindicated)
Mitral valve disease: (bb used, treat before pregnancy, HF may develop in late pregnancy)
Myocardial infarction
Peripartum cardiomyopathy: causes HF and specific to pregnancy.
What is peripartum cardiomyopathy?
rare (1 in 3000) cause of heart failure and specific to pregnancy
develops in the last month or first 6 months after pregnancy
frequently diagnosed late
cause of maternal death (risk 15%) and in more than 50% leads to permanent LV dysfunction
treatment is supportive with diuretics and ACE-I
there is a significant recurrence rate if subsequent pregnancies
