Other Medical Disorders in Pregnancy Flashcards
Why does glucose tolerance decrease in pregnancy?
Due to altered carbohydrate metabolism and the antagonistic effects of human placental lactogen, progesterone and cortisol
What do we mean when we say pregnancy is ‘diabetogenic’?
women without diabetes, but with impaired or potentially impaired glucose tolerance often deteriorate enough to be classified as diabetic in pregnancy
Even slightly increased glucose levels have adverse pregnancy effects - they are reduced by treatment
at what threshold do the kidneys of non-pregnant women start to excrete glucose?
How does this change in pregnancy?
11mmol/L
Varies more, but often decreases, so glycosuria may occur at physiological blood glucose concentrations
urinalysis for glycosuria is not a useful diagnostic test
What is the result of raised foetal blood glucose levels?
Foetal hyperinsulinaemia
causing foetal fat deposition and excessive growth - macrosomia
What % of pregnant women are affected by pre-existing diabetes?
1%
In those on insulin, increasing amounts will be required in these pregnancies to maintain normoglycaemia
What is gestational diabetes?
Gestational diabetes refers to diabetes triggered by pregnancy. It is caused by reduced insulin sensitivity during pregnancy, and resolves after birth.
What is the NICE threshold for gestational diabetes?
normal:
Fasting: < 5.6 mmol/l
At 2 hours: < 7.8 mmol/l
Results higher than these values are used to diagnose gestational diabetes.
It is really easy to remember the cutoff for gestational diabetes as simply 5 – 6 – 7 – 8.
What are the foetal complications of gestational diabetes?
Congenital abnormalities - NTD (2-4 Ames more common in women with established diabetes and are related to periconceptual glucose control)
Preterm labour (natural or induced) occurs in >10% women with established diabetes
Fetal lung maturity - less than with non-diabetic pregnancies
Birthweight - increased
Dystocia - and birth trauma: baby larger. related particularly to poor 3rd trimester glucose control
Why does gestational diabetes result in large babies?
foetal pancreatic islet cell hyperplasia leads to hyperinsulinaemia and fat deposition - this leads to increased urine polyhydramnios
What are the maternal complications of gestational diabetes?
Insulin requirements - increase by up to 300% by the end of pregnancy
Ketoacidosis - rate but hypoglycaemia may result
UTI
Wound or endometrial infection
Hypertension and pre-eclampsia
Pre-existing ischaemic heart disease
C-section or instrumental delivery
Diabetic nephropathy (5-10%)
can lead to massive proteinuria and deterioration of maternal renal function
Diabetic retinopathy - often deteriorates in pregnancy - may need to be treated
What is the preconceptual care of diabetes?
Glucose levels need to be optimum at conception to reduce risk of fatal complications.
HbA1c <6.5% and pregnancy not advised if >10%. Fasting glucose should be 4-7mmol/K if achievable without hypoglycaemia. Metformin and insulin are appropriate, but others must be stopped
5mg folic acid
Statins stopped and anti-hypertensives (labetalol/methyldopa) given instead
Renal function (creatinine <120umol/L), BP and retinae are assessed
What is the aim for glucose levels in pregnancy?
Fasting <5.6mmol/L
1hr <7.8mmol/L
What other measures need to be taken during pregnancy to Monitor for diabetes?
Renal function checked and retinae screened for retinopathy - if abnormal, this needs to be repeated every trimester
Aspirin (75mg) daily from 12 weeks advised to reduce risk of pre-eclampsia
Foetal monitoring: fetal echo, USS to monitor growth and liquor volume at 32 and 35 weeks
At what week gestation is delivery advised for diabetic women?
37-39 weeks as birth trauma more likely
C-section where estimated foetal weight is >4kg.
During labour, glucose levels are maintained with sliding scale of insulin and dextrose infusion
Why does the neonate commonly develop hypoglycaemia?
What is the management of this?
become accustomed to hyperglycaemia and therefore has high insulin levels
Levels should be checked within 4 hours - breastfeeding Is strongly advised
What are the factors indicating screening for gestational diabetes?
Previous large baby (>4.5kg) Unexplained stillbirth 1st degree relative with diabetes BMI >30kg/m2 Minority ethnic family origin Previous gestational diabetes Large for dates fetus
Women with pregnancy factors - e.g. polyhydramnios or persistent glycosuria
What is the screening for gestational diabetes?
24-28 weeks:
An OGTT
The patient drinks a 75g glucose drink at the start of the test. The blood sugar level is measured before the sugar drink (fasting) and then at 2 hours.
Hba1c levels to identify pre-existing diabetes.
Target levels are the same in pre-existing diabetes
What is the management of gestational diabetes?
Initially managed with diet and exercise advice.
Fasting glucose less than 7 mmol/l: trial of diet and exercise for 1-2 weeks, followed by metformin, then insulin
Fasting glucose above 7 mmol/l: start insulin ± metformin
Fasting glucose above 6 mmol/l plus macrosomia (or other complications): start insulin ± metformin
What % increase of CO is there in pregnancy? Why does this occur?
40%
Due to increase in stroke volume and heart rate and a 40% increase in blood volume
50% decrease in systemic vascular resistance, so BP often drops in 2nd trimester but has returned to normal by term
What % women have a flow murmur during pregnancy?
90%
What ECG changes are seen in pregnant women?
left axis shift and inverted T waves
What % of women are affected by cardiac disease?
0.3%
why does cardiac disease occur in pregnancy?
Increased Co –> exercise test (heart may be unable to cope)
decompensation in association with blood loss and fluid overload >28 weeks or soon after labour
Fluid overload can also occur in early puerperium as the uterine involution squeezes a large fluid load into the circulation
How are patients assessed pre-pregnancy for cardiac disease?
echo
contraindication of some drugs - ACEi and warfarin
hypertension often managed by beta-blockers ad thromboprophylaxis by LMWH
Fluid balance important = elective epidural analgesia reduces after load - elective forceps helps avoid the additional stress of pushing in severe cases
What are the types of cardiac disease that can onset in pregnancy?
Mild abnormalities - e.g. mitral valve prolapse, PDA, uncomplicated VSD/ASD
Pulmonary HTN - e.g. eisenmenger’s because of high maternal mortality, pregnancy = contraindicated
Cyanotic heart disease without pulmonary HTN - usually corrected but there is a particular risk of paradoxical embolism. anti-coagulation is advised
Aortic stenosis - severe disease causes an inability to increase CO when required and should be corrected before pregnancy. Beta-blockage
epidural analgesia is contraindicated in the most severe cases
Mitral valve disease - should be treated before pregnancy.
MI
Peripartum cardiomyopathy
How is mitral stenosis treated in late pregnancy?
Beta-blockade used
artificial metal valves are prone to thrombosis, so anti-coagulation is indicated
When does permpartum cardiomyopathy tend to develop?
Last month or first 6 months after pregnancy
Frequently diagnosed late.
Cause of maternal death and more than 50% leads to permanent LV dysfunction.
What is the management of peripartum cardiomyopathy?
Supportive - diuretics and ACE-i
Significant recurrence rate if subsequent pregnancies
By what volume is tidal volume increased by in pregnancy
40% - no change in respiratory rate
What common respiratory condition is common in pregnancy?
asthma
Why do women on long-term steroids require an increased dose in labour?
chronically suppressed adrenal cortex is unable to produce adequate steroids for the stress of labour
What % of women does epilepsy affect?
0.5% - seizure control can deteriorate in pregnancy (particularly in labour)
How are epileptic women managed in pregnancy?
Epilepsy = significant cause of maternal death
Anti-epileptic treatment should be continued, however, the risk of congenital abnormalities (NTD) is increased due to drug therapy. risk = dose dependent, higher with multiple drug usage and certain drugs
Seizure control with as few drugs as possible + folic acid (5mg/day)
Valproate avoided
Vit-K for enzyme inducing anti-epileptics
What is the risk of the new born developing epilepsy if the mother is epileptic?
3%
What drugs are safest for epilepsy in pregnancy?
Levetiracetam, lamotrigine and carbamazepine are the safer anti-epileptic medication in pregnancy
Sodium valproate is avoided as it causes neural tube defects and developmental delay
Phenytoin is avoided as it causes cleft lip and palate
When does foetal thyroxine production begin?
12 weeks
Before foetuses start producing thyroxine, where do they get their thyroxine from?
other - maternal TSH is increased in early pregnancy
What are the causes of hypothyroidism in pregnant women?
Hashimoto’s thyroiditis or thyroid surgery
What are the associated risks of hypothyroidism in pregnancy?
untreated - high perinatal mortality
subclinical - miscarriage, preterm delivery and intellectual impairment in childhood.
Increased risk of pre-eclampsia , particularly if antithyrozine antibodies are present
What is the cause of hyperthyroidism in pregnant women?
Grave’s disease
What is the result of untreated hyperthyroidism?
perinatal mortality
anti-thyroid antibodies can cross the placenta and cause neonatal thyrotoxicosis and goitre.
For the mother, thyrotoxicosis may improve in late pregnancy, but poorly controlled disease can lead to a ‘thyroid storm’
What is hyperthyroidism treated with?
Propylthiouracil (PTU) in the 1st trimester rather than carbimazole, but it can cross the placenta and cause neonatal hypothyroidism
What is postpartum thyroiditis?
Common condition causing post-natal depression
Usually a transient and subclinical hyperthyroidism at about 3 months postpartum followed by about 4 months by hypothyroidism - permanent in 20%
What are the risk factors for portpartum thyroiditis?
anti-thyroid antibodies and T1DM
What is the incidence of acute fatty liver in pregnancy?
Very rare (1 in 9000) - serious condition that is part of the spectrum of pre-eclampsia
What are the early features of acute fatty liver?
malaise, vomiting, jaundice and vague epigastric pain
thirst may occur weeks earlier
What is the management of acute fatty liver in pregnancy?
early diagnosis and prompt delivery - correction of clotting defects and hypoglycaemia are needed first
Treatment = then supportive; further dextrose, blood products, careful fluid balance and occasionally dialysis
What are the clinical features of intrahepatic cholestasis of pregnancy?
Unexplained pruritus
Abnormal LFT
Raised bile acids
What is the cause of obstetric cholestasis?
Obstetric cholestasis is characterised by the reduced outflow of bile acids from the liver.
thought to be the result of increased oestrogen and progesterone levels.
Occurs in 0.7% women
familial
tends to reoccur (50%)
What are the associated risks of obstetric cholestasis
Increased risk of stilbirth?
Meconium passage
PPH - stillburth is thought to be due to the toxic effects of bile salts