A 42-year-old woman is referred by her general practitioner with breathlessness for the past 3 days. She is 34 weeks pregnant in her third pregnancy. Prior to this she has had an emer- gency Caesarean section for abnormal cardiotocograph in labour, followed by a 7-week miscarriage.
In this pregnancy she was seen by the obstetric consultant to discuss plans for delivery, and is hoping for a vaginal delivery. Ultrasound scans and blood tests have been normal. Her booking blood pressure was 138/80 mmHg and has remained stable during the pregnancy.
She describes her shortness of breath starting while she was at work and slightly worsen- ing since. She felt particularly breathless when she ran to catch a bus on her way home yesterday. She has some left-sided chest pain on breathing in. There is no cough or haemoptysis. She has had no previous episodes. She has not noticed any calf pain but has left leg swelling and some back pain.
The body mass index is 28 kg/m2. The woman does not look obviously unwell. Blood pre- ssure is 127/78 mmHg and heart rate 98/min. Oxygen saturation is 96 per cent on air. On examination of the chest there is a systolic murmur and no added sounds. Chest expan- sion is normal but the woman reports pain on taking a deep breath. The chest is resonant to percussion and chest sounds are normal except for a pleural rub on the left. The left leg is generally swollen but no redness or tenderness is apparent.
· What is the diagnosis?
· What further imaging is required?
· How would you manage this woman in the immediate term, during delivery and postnatally?
The diagnosis is of pulmonary embolism (PE). The shortness and breath and pleuritic chest pain are classic features, and the ECG and blood gas analysis support the diagnosis. D-dimer is commonly raised in pregnancy but also supports the diagnosis. The CTPA demonstrates a large filling defect within the right pulmonary artery and a smaller filling defect in the left segmental pulmonary artery, consistent with blood clots (pulmonary embolism). These findings are illustrated by the arrows in Fig. 93.2.
Venous thromboembolism (VTE) is the leading cause of direct deaths in the Confidential Enquiry into Maternal and Child Health, accounting for death in 1.2 per 100 000 mater- nities. Non-fatal VTE occurs in approximately 60 in 10 000 pregnancies, and there may be many more unrecognized cases. Pregnancy itself is a risk factor because of the hyper- oestrogenic state, the altered blood viscosity and obstruction to venous blood flow by the gravid uterus.
There is no clinical evidence of calf ileofemoral deep vein thrombosis, but generalized leg swelling and back pain are suspicious of an ileofemoral thrombosis. If this is confirmed, which may require Doppler ultrasound or magnetic resonance imaging (or if she develops recurrent PE despite anticoagulation), then liaison with a vascular team should be consid- ered regarding the possibility of insertion of a vena caval filter.
As with non-pregnant patients, anticoagulation is the mainstay of treatment. Warfarin is contraindicated in the first trimester of pregnancy but may safely be given from 12 to 36 weeks. However it can cause difficulties with excessive bleeding if it is not stopped early enough before delivery and it can be difficult to achieve stable international normalized ratio levels. Therefore low-molecular-weight heparin has become the treatment of choice in pregnancy as it is simple to administer, relatively easy to reverse in the emergency situ- ation, does not require monitoring, and is safe.
At delivery the heparin should ideally be discontinued 12 h before delivery and recom- menced immediately following delivery. Similarly an epidural or spinal anaesthetic should not be administered immediately after a heparin dose.
Postnatally some women change to warfarin, which is now known to be safe with breast- feeding, while others continue low-molecular-weight heparin.
A large proportion of VTE occurs postnatally, so anticoagulation should be continued for 6 weeks to 3 months in the puerperium.
Graduated elastic compression stocking should be worn from the time of diagnosis until at least 6 weeks following delivery, to reduce the risk of the post-thrombotic syndrome (chronic leg pain, swelling and ulceration).
Postnatal investigation for inherited (e.g. protein C or S deficiency) or acquired (e.g. anti- phospholipid syndrome) thrombophilia is appropriate, as is anticoagulation throughout any subsequent pregnancy.