Pulmonary Embolus (PE) In Pregnancy

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1 Pulmonary Embolus (PE) In Pregnancy Information for Patients What is a venous thrombosis? Venous thrombosis is a blood clot within a vein. Veins are the blood vessels that take blood to the heart and lungs. Venous thrombosis often occurs in one of your legs, with the left leg being more commonly affected. Symptoms include a red, hot and swollen leg that can be painful. What is a pulmonary embolus? A pulmonary embolus (PE) is a blood clot within the lungs. When a blood clot (thrombus) forms in the body, a part of it can break off and travel round the body. This broken off part is called an embolus. The embolus travels within the vein until it reaches a narrow section and gets stuck. This is often in the lungs, where it is called a pulmonary embolus. Is a PE serious? A PE is potentially life threatening. Prompt treatment saves lives and luckily dying from a PE is very rare in women who are pregnant or after child birth. Symptoms of a PE include: Sudden difficulty in breathing, without an explanation. Chest pain Chest tightness

2 Collapsing or feeling very unwell If you have any of the above symptoms, seek medical help immediately. Who is at risk of DVT and PE? The risk of blood clots is increased during pregnancy and for the first six weeks after the birth of your baby. This is due to normal changes in your blood during pregnancy. The risk of woman who is not pregnant developing a blood clot is 1 in 5,000. During pregnancy the risk is 1 in 500, which is ten times greater. You are at increased risk of venous thrombosis if you: are 35 years or older have had a blood clot in the past have a parent or sibling who has had a blood clot have a thrombophilia a condition that increases risk of blood clots are obese with a body mass index (BMI) over 30 smoke become dehydrated are immobile for long periods of time How is a PE diagnosed in pregnancy? The tests for a PE include: Chest X- ray this is often done first as it can also identify common problems with similar symptoms such as a chest infection. CTPA this is a specialised x- ray of your lungs called a computed tomographic pulmonary angiopraphy. It requires a drip in the back of your hand and injection of an x- A normal chest X- ray. ray dye. Q scan this is a perfusion scan of your lungs that uses a small amount of radioisotope and a special camera to look at blood flow in the lungs. It also requires a drip in the back of your hand. The test perfomed at Leeds Teaching Hospitals uses only half the radioisotope activity of a conventional Q scan, and is known as a half- dose Q scan.

3 Are there any risks? Each of the above tests uses radiation. The theoretical risk from radiation used in any diagnostic scan is that it may induce cancer. These risks must always be considered in the context of the natural background risk that all of us have of developing cancer. Risks should also be balanced against the need to exclude a potentially serious PE. Risks to your baby: - The chest X- ray uses a very small radiation dose and your baby is covered with a protective sheet, so the risks from this are negligible. - Risk of childhood cancer as a result of either of these tests is very small. Natural background risk of childhood cancer is 3 in 10,000. o Risk from half- dose Q scan (as performed in Leeds Teaching Hospitals) is approximately 1 case from 500,000 scans. o Risk from a CTPA is approximately 1 case from 1,000,000 scans. Risk is higher from Q scan, although is still very small. In comparison to normal risk, either test will not significantly increase risk of childhood cancer. Your baby will be exposed to more radiation from the environment during pregnancy that is delivered in a Q scan or CTPA. Risks to you: - CTPA carries significantly more risk to you than a Q scan. It delivers a large dose of radiation to your breasts, 16 times greater than from a Q scan. This is associated with a 14% increased risk of developing breast cancer. On balance, the medical team looking after you would reason that the theoretical risks associated with these tests are outweighed by the real risk of potential harm to you or your baby if a PE remains undiagnosed. You will have the opportunity to discuss these investigations with your medical team during your admission. Breastfeeding advice: If you develop a PE in the period after giving birth, breastfeeding should be avoided for 12 hours after a Q scan. Milk can be expressed before the scan and stored. Milk can also be expressed and thrown

4 away during the 12 hour period, for breast comfort. Breastfeeding is safe after a CTPA. Which test will I have? This is based upon specific guidelines that have been developed at Leeds Teaching Hospitals for the investigation of PE in pregnancy and will depend upon discussions with your doctor and healthcare team and also on the results of your chest X- ray. What is the treatment for DVT and PE? If your doctor suspects that you have a PE, you will be advised to start treatment with a medication called heparin (an anticoagulant) to reduce blood clotting (sometimes referred to as thinning the blood ). The most commonly used heparin in pregnancy is low molecular weight heparin. Heparin is given as an injection under the skin every day. You or a family member, will be shown how to do the injections. You will be supplied with needles and syringes with the heparin in them. Regular check- ups will be arranged as an outpatient, so you will probably not need to stay in hospital. What are the benefits of treatment? The benefits of heparin are that it: stops the clot getting bigger this helps your body to dissolve the clot over time reduces the risk of another venous thrombosis or PE developing lowers the risk of long- term symptoms wearing compression stockings reduces the risk of long term damage to leg veins, which can cause unsightly veins, discolouration and swelling. What are the risks of treatment? Low molecular weight heparin does not cross the placenta and therefore cannot harm your baby.

5 You may get some bruising where you inject these usually fade within a few days. One or two women in every 100 (1% to 2%) have an allergic reaction, usually a rash. If you notice a rash after taking heparin, tell your doctor so that they can change the type of heparin. Women who go into labour and are having heparin injections have a higher risk of bleeding after delivery and of developing a wound haematoma (bruise) after a Caesarean section. In addition you will not be able to have an epidural sited unless 24 hours have passed from your last heparin injection. It will not affect other forms of pain relief, these will be available during the 24 hour period. Similarly, if you need to go to theatre for an intervention you will need to be put to sleep as a spinal anaesthetic is deemed unsafe unless 24 hours have passed from your last injection. For this reason you may be offered an induction of labour to make plans to stop your heparin injection in time prior to delivery. How long will I have to take heparin for? It is usually recommended that heparin is taken for the remainder of pregnancy and for at least six weeks after birth. If you suspect a PE, can t you just treat me without the investigations? It is important to know whether you developed a PE so as not to have heparin injections unnecessarily. In addition it is important to know whether you developed a PE as you will need heparin injections to prevent another blood clot developing in a subsequent pregnancy. What should I do if I go into labour whilst taking heparin? If you think you are going into labour, do not have any more injections. Phone your maternity unit and tell them you are on heparin treatment. They will give you advice on the phone.

6 What if I have a caesarean section? If the caesarean section is planned, your last heparin injection should be 24 hours before the planned caesarean delivery. The heparin will then usually be started within 4 hours of the delivery. What happens after birth? Treatment will be continued for at least 6 weeks after the birth of your child. The duration of your injections after delivery will depend on when you developed your blood clot during the pregnancy and its severity. There is the choice between continuing with injections of heparin, or switching to warfarin tablets. Your doctor will discuss both options with you. After the birth, you will usually be offered an appointment with either your GP or obstetrician to discuss: family history of blood clots if people in your immediate family have also had blood clots, your doctor may discuss tests for a condition that makes blood clots more likely (thrombophilia). Future contraception you should be advised not to take any contraception with oestrogen in it, for example the combined pill Future pregnancies you will be recommended heparin throughout pregnancy and after your next pregnancy Can I breastfeed? Yes both heparin and warfarin are safe to take when breastfeeding. As mentioned above, if you are having a Q scan after delivery of your baby, breastfeeding should be avoided for 12 hours after. Breastfeeding is safe after a CTPA.

7 References 1. Royal College of Obstetrics and Gynaecology Treatment of venous thrombosis in pregnancy and after birth. Published 01/09/ leaflets/treatment- of- venous- thrombosis- in- pregnancy- and- after- birth/ 2. Venous Thromboembolism in Pregnancy Published 20/12/ thromboembolism- in- pregnancy Written by Emily Holt (5 th year medical student) with help from Dr E. Ciantar (Obstetric Consultant) and Dr F. Chowdhury (Nuclear Medicine Consultant).