Thrombosis, which is the clotting of blood within the blood vessels, is a serious but fortunately uncommon complication in pregnancy.
When thrombosis occurs, treatment is necessary and will need to be continued for the remainder of the pregnancy and for several weeks beyond.
Apart from being a painful condition, deep vein thrombosis - or DVT, as it is known in the short form - requires treatment in the form of injections during pregnancy. These have to be administered at least once a day, every day. Though clearly unpleasant, this is necessary.
When a clot is dislodged, it is transported via the bloodstream to the heart and ultimately to the lungs. At that point, the matter is deadly serious. This is what is known as pulmonary embolism, a highly dangerous complication.
Pulmonary embolism has remained one of the three leading causes of maternal death in the developed world for many years now.
Even without the potentially fatal complication of pulmonary embolism, deep vein thrombosis can cause chronic problems; as we shall discuss shortly. With proper information, most affected mothers are adequately motivated to continue with treatment.
Deep Vein Thrombosis (DVT) in pregnancy: Risk factors
Where does thrombosis commonly take place?
In the deep-lying veins. The veins in the calves, as well as the inside upper part of the thighs, are particularly prone.
There are two major types of blood vessels in the body. These are veins and arteries. The function of veins is to take blood from all parts of the body back to the heart. The arteries take freshly oxygenated blood from the heart to all parts of the body. Thrombosis in the arteries is extremely rare and occurs only in special circumstances, as we shall see later.
Are there any factors that increase the likelihood of deep vein thrombosis (DVT)?
Yes. Some factors are known to increase susceptibility to this problem. Among the leading factors are:
High parity: The higher the number of deliveries in the past, the higher the risk. It means, all other things being equal, a mother in her fifth pregnancy is at a higher risk of DVT compared to in the first pregnancy.
Obesity: An expectant mother who is overweight is at an increased risk of DVT. The increase in risk is roughly in a linear fashion: the higher the weight, the higher the risk.
Immobilization: Prolonged lack of physical activity during pregnancy (which may range from enforced confinement to bed or lounging about in front of the television interminably, to long-haul air travel) are recognized risk factors especially in late pregnancy.
Caucasian race: There is a clear ethnic difference in susceptibility to thrombosis. Women of Asian and African ancestry are less susceptible when compared to Caucasian women.
The older mother: Pregnancy in the late thirties and afterwards is associated with increased risk of thrombosis.
Dehydration: Inadequate fluid intake in the face of excessive fluid loss, be it through vomiting, diarrhoea, vigorous exercise etc. leads to dehydration. This increases the risk of thrombosis.
Previous history: A pregnant mother with a past history of thrombosis or thrombo-embolism, even if this was not during pregnancy, is at a higher than average risk of thrombosis complicating her pregnancy.
Of course, these factors may not appear in isolation. As such, if a mother in early pregnancy is at a weight of 95 kg, age 37, in her sixth pregnancy and complains of a backache which is confining her to the settee most of the day, even in the absence of a previous history of thrombosis, she is clearly high risk.