Which one of the following patients would you advise to avoid pregnancy?
Pregnancy is well tolerated in most patient groups, even those with a Fontan circulation. It is extremely high risk in patients with severe systemic ventricular impairment, those with a dilated aorta, those with pulmonary hypertension, and those with severe obstructive valve lesions due to the high risk of maternal morbidity. These patients should be counselled against pregnancy. The risk of mortality in patients with pulmonary hypertension is high. It has remained one of the leading causes of death in pregnancy for many decades, along with myocardial infarction, aortic dissection, and peripartum cardiomyopathy. Furthermore, bosentan is contraindicated in pregnancy.
A 36-year-old patient with repaired ToF wishes to become pregnant and asks you about the likelihood of her child being born with a congenital heart defect. She has no family history of congenital heart disease.
What is the approximate risk of her child having congenital heart disease?
Most congenital heart disease is multifactorial in origin. There are some familial syndromes and some with autosomal dominant inheritance but generally the risk of inheritance of many lesions is 4–5%. Patients with left-sided obstructive lesions and atrioventricular septal defects have a slightly higher risk of passing on a defect—in the region of 6–8%. The risk of defects being passed on by fathers is lower.
A GP writes to you to ask which contraceptive is advisable for her 35-year-old patient with a mechanical mitral valve replacement. She has had one child and several miscarriages because of taking warfarin. She does not wish to become pregnant again.
What is the best method of contraception for this patient?
Patients with heart disease are often unaware of the most suitable contraception for them and the quality of advice offered is universally poor. Generally speaking, progesterones (including the morning-after pill) are safe for all cardiac conditions. Condoms have a high failure rate and should not be used in women in whom avoiding pregnancy is important. The combined pill should be avoided in those in whom clotting is hazardous, i.e. dilated cardiomyopathy, Fontan, Mustard/Senning, AF/atrial flutter, previous clot, cyanosis/shunt, pulmonary hypertension, and mechanical valves. The progesterone implant and progesterone coil (Mirena IUS) are well tolerated and much more effective than sterilization. Consideration needs to be given to women on warfarin because of the risk of heavy/irregular bleeding with the mini-pill or Depo. Additionally Depo and implanted devices can result in painful bruising at the site of injection. The Mirena coil results in a lighter period, which is useful for women on warfarin and is highly effective.
In current regulations, which of the following drugs is absolutely contraindicated in pregnancy?
Statins are categorized by the FDA as Category X because they inhibit mevalonic acid and have been shown to cause skeletal abnormalities in fetuses as well as resulting in fetal death. Although it has been proposed that statins in pregnancy may have benefits for treatment of pre-eclampsia this remains unproven and is not an accepted clinical indication. Atenolol, clopidogrel, and amlodipine can be used in pregnancy if the benefit to the mother outweighs the risk to the fetus. Aspirin is best avoided in the first trimester but is safe later in pregnancy in doses of <150 mg od.
A 35-year-old woman with a history of atrioventricular nodal tachycardia presents in premature labour at 36 weeks with a narrow complex tachycardia at 180 bpm (see ECG below).
What is the most appropriate drug to use after vagal manoeuvres and adenosine?
Tachyarrhythmias in labour are often catecholamine driven and therefore beta-blockers are the most effective and appropriate drugs. The short half-life of esmolol is useful as it terminates the tachyarrhythmia without having a prolonged effect on labour. The others are less likely to be effective. Amiodarone is contraindicated in pregnancy.
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