Medical Disorders in Pregnancy

Dr Than Than Yin

Obstetric cholestasis

• Unique to pregnancy• Severe pruritus affecting limbs and trunk

mainly palm and sole• Developing in the second half of pregnancy

(usually during the third trimester)

Diagnosis• A typical history of pruritus without rash• Abnormal liver function tests– Moderate < less than three-fold elevation in

transamimases ( ALT is the most sensitive)– Raised ALP 9> pregnancy values– Raised Ƴ glutamyl transpeptidase – Mild elevation of bilirubin– Increased total serum bile acid

• Exclusion of other causes of itching and abnormal liver function

Diagnosis

• To exclude other causes of abnormal liver function

• Liver scan• Viral serology ( for hepatitis A,B,C and E,EBV

and CMV)• Liver autoantibodies( for pre-exisisting liver

diseasse, anti-smooth muscle antibodies, antimitochondrial antibodies

Management• Counselling • Weekly LFT and bile acids • No evidence of monitoring fetal well-being• To check prothrombin time prior to delivery

Intrapartum management

• Labour may be induced at 37-38 weeks gestation if persistantly raised bile acid levels

• If bile acid levels < 40 µmol/L, reasonable to await spontaneous onset of labour

Drug therapy

• Vitamin K mandatoroy for women with prolonged prothrombin time, commenced at 32 weeks

• Antihistamine• Ursodeoxycholic acid• Dexamethasone • Rifampicin • Cholestyramine • S-Adenosylmethionine • Activated charcol • Epomediol

Diagnosis

• BP, urinalysis, uric acid, platelet count, clotting screen, blood film

• Blood glucose, serum calcium, sodium, liver function tests

• CT or MRI• EEG

Epilepsy in pregnancy

• Many cases are idiopathic• 30% have a family history of epilepsy• Secondary Epilepsy – Previous surgery– Intracranial mass or lesions– Antiphospholipid syndrome

Effect of pregnancy on epilepsy• A common indirect maternal death• No effect in majority• Women who have been seizure free for years are

unlikely to have seizures in pregnancy• Women with multiple type seizures are more likely

to have increase in seizure frequency• The risk of seizures is highest in peripartum• Sudden Unexplained Death in Pregnancy (SUDEP)-

risk factors – seizure frequency– Increasing number of antiepileptic drugs– Low IQ– Early onset epilepsy

Effect of epilepsy on pregnancy

• The fetus is relatively resistant to short periods of hypoxia

• No increased risk of miscarriage or obstetric complications

• Status epilepticus is dangerous for both mother and fetus

• The risk of child developing epilepsy is increased (4-5%) if either parent has epilepsy and, risk is 10-15% if both parents have epilepsy, 10% risk with previously effected sibling

Teratogenic risk of anti-epileptic drugs(AED)

• Phenytoin, primidone, phenobarbitone, carbamazepine, sodium valproate, lamotrigine, topiramate and levetiracetam all cross the placenta and are teratogenic

• Major malformations caused by AEDs– Neural tube defects ( especially valproates 1-3.8% and

carbamazepine 0.5-1%)– Orofacial clefts ( particularly Phenytoin, carbamazepine,

phenobarbitone and valproate)– Congenital heart defects (particularly Phenytoin,

phenobarbitone and valproate)• Minor malformations

– Dysmorphic features– Hypertelorism– Hypoplastic nails and distal digits– Hypoplasia of the mid face

Teratogenic risk of anti-epileptic drugs(AED)

• Metaanalysis of all studies showed that the risk of any one drug is approximately 6-7%

• Various theories– Genetic deficiency of the detoxifying enzyme

epoxide hydrolase– Cytotxic free radicals– Folic acid deficiency

Management • Antenatal management

– Folic acid 5mg daily– No need to change the AED if epilepsy is well controlled– Pre-natal screening for congenital abnormalities and detailed

ultrasound at 18-20 weeks should be ordered, including fetal cardiac assessment

– Vitamin A 10-20mg daily should be prescribed in the last four weeks of pregnancy

• Intrapartum management– Risk of seizures increase around the time of delivery– 1-2% will have a seizure during labour and 1-2% will have a

seizure in post partum 24 hours period– Should continue regular AED– Effective pain relief and epidural analgesia

• Postnatal management– The neonate should recieve 1mg Vitamin K Inj IM– Breast feeding should be encouraged

Cardiac disease in pregnancy

• Leading cause of maternal death as result of – Myocardial infarction– Ischemic heart disease– Dissecting aortic aneurism

• Other heart disease– Peripartum cardiomyopathy– Rheumatic heart disease- 25% of pregnant

population who not born in the UK– Congenital heart disease

Management • Preconception counselling• Antepartum

– Risk assessment– Joint clinic attended by obstetrician, cardiologist, anaesthetist– Echocardiogram– Fetal echocardiogram for women with congenital cardiac disease– 32-34 weeks gestation –multidisciplinary meeting for birth plan

• Intrapartum – Early slow incremental epidural analgesia, assisted vaginal delivery– Caesarean section is only necessary for obstetric indications

• Postpartum – Anticoagulation– Long observation in high dependency area– Prophylaxis against postpartum haemorrhage

• Low dose oxytocin infusion

Thyroid disease in pregnancy Hyperthyroidism

• Thyrotoxicosis complicates in 1 in 500 pregnancies

• 50% of affected women have a positive family history of autoimmune thyroid disease

• 95% are due to Grave’s disease, an autoimmune disorder caused by TSH receptor stimulating antibodies

Hyperthyroidism

• 1% of pregnancies• Most cases have already

been diagnosed• Associated with

autoimmune diseases, pernicious anemia, vitiligo, type 1 diabetes

• Commonest causes encountered in pregnancy- Hashimoto’s thyroiditis, treated Grave’s disease

TSH(MU/l) Throxine (pmol/L)

Triiodothyronine (pmol/L)

Non-pregnant 0.27-4.2 12-22 3.1-6.8

1st trimester 0-5.5 10-16 3-7

2nd trimester 0.5-3.5 9-15.5 3-5.5

3rdt trimester 0.5-4 8-14.5 2-5.5

Pregnancy –specific normal ranges