Are you pregnant? Get up and move, as you could be more vulnerable to Deep Vein Thrombosis (DVT) when you are expecting.
Deep vein thrombosis (DVT) is more commonly known as the ‘economy class syndrome’. It can happen when a blood clot that starts in the deep veins of lower limbs dislodges and travels in the bloodstream. But did you know that pregnant women are five times more vulnerable to DVT – whether or not they are on a flight?
It happened to Grand Slam champ Serena Williams. When her baby Alexis Olympia’s heart rate dropped drastically as the tennis champion was in labour, Williams had to have an emergency Caesarean section. Shortly after the procedure, she developed a pulmonary embolism. This is a life-threatening condition where a blood clot makes its way to the lungs.
She could not breathe, and was coughing so intensely that her C-section wound opened up. Williams has since shared her experience to increase awareness of the issue, and champion women’s access to health care. But the worry never goes away.
In January this year, at the Australian Open, the 37-year-old wore fishnet compression stockings for her first-round match. She told reporters there that she was “definitely still concerned”. “With DVT, it’s very scary… Especially for me, it’s incredibly frightening. I lay on the side of precaution as opposed to not,” she said.
So what is this condition that scares even the world’s greatest female tennis player?
What is DVT?
Let’s start from the beginning. The term ‘thrombosis’ refers to the formation of potentially deadly blood clots. A blood clot that starts in the vein (instead of the artery) is known as venous thromboembolism (VTE). The most common of these occur in the deep veins of the legs, hence the term ‘deep vein thrombosis’, explains Dr Tony Tan, a Specialist in Obstetrics and Gynaecology & Consultant at the Raffles Women Centre.
DVT occurs when blood in the body slows down or stops flowing. This happens when there is:
1. Not enough movement (or no movement)
2. ‘Thicker’ hypercoagulable blood (which occurs during pregnancy) and/or
3. Damage to the deep veins either because of trauma or inflammation
Clots can dislodge from the original locations where they were formed and travel in the blood, causing an embolism. This then becomes stuck in a narrower blood vessel elsewhere in the body, says Assoc Prof Lee Lai Heng, Senior Consultant, Dept of Haematology, Singapore General Hospital.
When the blood clot dislodges and travels to the lung blood vessels, it can prove fatal for patients. This is known as pulmonary embolism (PE).
Will I get DVT?
You may never know. Both deep vein thrombosis and pulmonary embolism are known as ‘silent diseases’ as their symptoms are non-specific. In DVT of the lower limbs, the common symptoms are pain, swelling, and redness of the affected limb.
With PE (pulmonary embolism), symptoms can be mild – like shortness of breath, giddiness. If serious, you may experience chest pain or tightness, coughing out of blood, hypotension (low blood pressure), fainting spells, collapse, and death.
Pregnancy increases a woman’s risk of DVT by four- to five-fold, compared to non-pregnant women of similar age. This occurs in about 1-2 per 1,000 deliveries in Caucasian populations. In Singapore, unpublished data indicates the rate to be around 0.5 per 1,000 deliveries.
While DVT is not very common condition in pregnancy, it’s good nevertheless to be educated about it as it is preventable, even in women who are at risk of developing VTE.
(See also: 10 Ways to Prep your Body for Optimum Fertility)
Am I at risk?
If you are female, these are the risk factors. You are
• above 35 years old
• a smoker
• had multiple pregnancies
• BMI > 30 kg/m2
• varicose veins
• previously delivered three or more babies
• a family history of unprovoked or oestrogen-provoked DVT in a first-degree relative
• pregnancy from in-vitro fertilisation or assisted reproductive techniques
• pre-eclampsia in the current pregnancy
• past history of DVT
Ways to help prevent DVT
• lead a healthy lifestyle to prevent being overweight
• stop smoking
• take measures to prevent immobilisation and dehydration
• if you have a known personal history of VTE or presence of multiple risk factors, blood thinners can be considered
• in situations where there is also increased risks of bleeding, mechanical methods such as calf compression pumps can be considered.
(See also: Genetic Carrier Screening in Singapore)
The need for DVT awareness
There are other factors that can make you more vulnerable to DVT. For instance, taking the combination birth control pill can triple your risk of DVT. Granted, the overall risk is low. However, it does boost the chances of getting blood clots especially if there are another conditions in its favour, such as long-haul travel.
A study by the Singapore General Hospital revealed that VTE (blockage of a blood vessel by a blood clot) is one of the leading causes of maternal mortality in Singapore. In fact, pregnancy-associated VTE in the Asian population is rising.
The number of women in Singapore conceiving in their 40s has doubled over the past three decades, therefore a higher awareness about the condition is key to ensure that preventive measures are taken. It also doesn’t help that there’s often a difficulty in diagnosis as symptoms can be overlooked, therefore it’s important to know what they are and seek medical treatment early in order to reduce complications from the clot.
As mentioned, this is preventable condition so it’s wise to be aware of the precautions to take during pregnancy.
“For low risk pregnant women, avoid prolonged rest or immobility, drink plenty of fluids and ambulate regularly,” says Dr Tan. “For scenarios like hospitalisations or when taking flights for more than four hours, or after a Caesarean section, wear elastic stockings and consider low molecular weight heparin injections to thin the blood. Your obstetrician will determine the risk score to decide if low molecular weight heparin is required.”