A risk-adapted approach is required

During pregnancy, the risk of a thromboembolic event increases. Why this is the case and when medical compression stockings are indicated during pregnancy is explained by Prof. Dr. med. Ekkehard Schleußner, Director of the Obstetrics Department at Jena University Hospital , Germany.

life: Why is thrombosis more common in pregnant women?

Prof. Schleußner: In the first place, this is related to hormonal changes. Pregnancy is a hypercoagulatory condition, which makes sense from an evolutionary perspective. The biggest risk during pregnancy and child birth – even today – is dying from a hemorrhage. Hormonal changes, an increased estrogen level in particular, result in an increase in the production of coagulation factors in the liver, while, at the same time, anticoagulant factors decrease.
Furthermore, the vascular wall changes. Not only because there are more coagulation factors and the docking points for them on the vascular walls are more active; but the muscles of the peripheral vessels also become wider, the tone of the blood vessels decreases. This, in turn, results in slower blood flow.
During the later stages of pregnancy, venous reflux from the lower extremities also becomes more difficult because the growing uterus presses on the inferior vena cava. The impaired return of the blood, in turn, expands the vessels etc. These factors, which were already specified by Virchow – slower blood flow and changes in the vascular walls as well as in blood composition – are the fundamental reasons why the risk of thrombosis is about six times higher in pregnant women.
The most dangerous time, apart from the actual childbirth, is the postpartum period. Changes in the hormone balance, loss of blood during childbirth and a changed blood composition as well as being bedridden, especially after a Cesarean section, among other factors, contribute to the fact that in the first six weeks after childbirth, there are, numerically speaking, as many thromboembolic events as in the nine months before. And we haven’t mentioned the individual risk factors yet that these women may also bring to the equation.

What other risk factors are you thinking of?

Prof. Schleußner: One critical factor is age. When I was a young physician, the average age of mothers at the time of childbirth was 23 years. Today, it’s 32. In addition, women are also more frequently affected by other personal risk factors with increasing age, such as varicose veins or previous thromboembolic events. Another risk factor that has hugely increased is being overweight. In Thuringia, almost one in four pregnant women is currently overweight , about one in six is obese. Hormone treatment to support fertility and artificial insemination double the risk of a thromboembolic event.
And then there are congenital or acquired thrombophilic risk factors, such as the Factor V Leiden mutation, antiphospholipid syndrome or disorders affecting the regulation factors protein S and protein C.

How should pregnant women and physicians respond to a higher risk of thrombosis?

Prof. Schleußner: Women should be as active as possible and drink a lot until childbirth. One reason is that the kidneys are supplied with more blood, and more urine is generated. Physicians need to consistently treat women with particular combinations of risks. If a pregnant woman has varicose veins or edema, for example, compression therapy should definitely be initiated.

When would you specifically recommend the use of medical compression stockings?

Prof. Schleußner: On the one hand, to treat symptoms when women suffer from heavy, painful legs or edema. This is the case for quite a number of women toward the end of pregnancy in particular. They then don’t just benefit from the stockings for their well-being but also for thrombosis prevention.
On the other hand, I’d recommend it for all those who have the relevant risk factors: whether it’s a family history of thrombosis or a prior thrombosis, thrombophlebitis, varicose veins, pre-eclampsia or a congenital coagulation disorder, such as a Factor V Leiden mutation. I then recommend that they wear compression stockings from the beginning of pregnancy.
It’s very important that , with some combinations, medical compression stockings are an essential part of thrombosis prevention, but they’re not sufficient by themselves – for example, in pregnant women where several risk factors accumulate, such as a medical history of thrombosis with an unknown origin and a Factor V Leiden mutation, varicose veins or obesity. In these cases, additional injections of low-molecular-weight heparin are needed. Taking acetylsalicylic acid, for example, isn’t enough to prevent thrombosis! The approach must therefore always be adapted to the risk. An advantage during this process is when you have a good network of colleagues from other disciplines, such as phlebologists, internists, rheumatologists, etc. who you can discuss potential risks with.

What do you bear in mind when prescribing compression stockings?

Prof. Schleußner: During pregnancy and postpartum, I will definitely prescribe thigh-high stockings with a closed toe and compression class 2, or suitable compression pantyhose. On the first prescription, two pairs can be specified straight away, which I think makes a lot of sense. After all , the women should wear these stockings every day – preferably until eight weeks after giving birth. Prescribing compression stockings doesn’t have an impact on the physician’s budget , by the way.

Image: Frank Steinhorst