Blood clot is a topic that makes everyone talk about “clot”, which can be disabling or fatal. The impression is that middle-aged and elderly people are usually prone to thrombosis, but there is a young group of people who are always threatened by thrombosis, and that is the young pregnant women. Venous thromboembolism is a common disease during pregnancy and is a common cause of maternal death. With the progress of urbanization, the phenomenon of late marriage and late childbirth is becoming more and more obvious, and there are more and more pregnant women over 30 years old. Advanced maternal age is one of the high-risk factors for thrombosis.
1. Why is maternity prone to thrombosis?
Maternal blood clots more easily as a self-protective mechanism of the human body. We call this medical phenomenon the hypercoagulable state of pregnancy, which is conducive to effective hemostasis and prevention of possible excessive blood loss during normal delivery or abortion, but also increases the risk of thrombosis and embolism. This hypercoagulable state persists throughout pregnancy until 8 weeks after delivery, resulting in a 4- to 5-fold increase in the incidence of thrombosis during pregnancy compared to other women of childbearing age, and an even higher 20-fold risk of thrombosis within 8 weeks after delivery.
In addition, the use of anesthetics during cesarean section can lead to relaxation of venous smooth muscle, while the use of postoperative analgesic pumps and prolonged bed rest keep the muscles in a state of prolonged relaxation, slowing blood flow and obstructing blood return to the lower extremities, which increases the prevalence of thrombosis in women who deliver by cesarean section. more than 80% of thrombotic sites occur in the lower extremities, that is, the parts of both legs, and other sites include the neck, intracranial, subclavian, and pulmonary embolism.
2.Is it contradictory to protect the fetus and treat thrombosis?
Many patients, especially women who found thrombosis in early pregnancy, had abortion because they found thrombosis and thought that the medicine for thrombosis would affect the fetus. Does it mean that if the fetus is preserved, the thrombosis cannot be treated, and if the thrombosis is treated, the fetus cannot be preserved? Actually, this is not true. Some women hear that untimely treatment of thrombosis can cause lifelong disability, so they abort the fetus, put a filter on it, dissolve the clot, and consider pregnancy when they recover.
For women in their twenties, it is not a bad idea, but for pregnant women over 30 or even 35 years old (35 years old is a watershed, over 35 years old is medically called advanced primigravida, the risk of pregnancy and the probability of fetal complications and malformations will increase dozens of times), many of them are conceived through IVF, reproductive technology, which is very difficult and the fetus is especially precious.
How can we preserve the fetus at this time without hindering the treatment of blood clots? The answer is that there is a way. The standardized, regular, adequate and full course of anticoagulation treatment under the guidance of doctors can effectively control and treat the thrombosis without affecting the fetal development and delivery.
3.How to standardize the treatment of deep vein thrombosis?
For deep vein thrombosis, anticoagulation therapy is the preferred treatment recommended internationally. Anticoagulation is the most effective treatment to prevent thrombosis progression and promote thrombosis recanalization. General anticoagulation therapy in non-pregnant women starts with heparin intravenously or low molecular heparin subcutaneously, overlapping with an oral anticoagulant, usually warfarin. During anticoagulation therapy, special attention should be paid to two aspects, one is to review regularly and the other is not to stop the medication on your own in the middle.
4.Will anticoagulation therapy cause fetal malformation?
Low-molecular heparin is recommended for the treatment of DVT in pregnancy. This drug does not cross the placenta, thus avoiding the teratogenic risk of warfarin. In the 9th edition of the American College of Chest Physicians Antithrombotic and Thromboprophylactic Practice Guidelines (ACCP-9), published in 2012, low-molecular heparin is recommended as the standard anticoagulant for the treatment of thrombosis in pregnancy and the perinatal period.
The advantages of low-molecular heparin include good bioavailability, long plasma half-life, predictable dose response, and less frequent occurrence of osteoporosis and heparin-induced thrombocytopenia, making low-molecular heparin the treatment of choice for patients with maternal thrombosis. Low-molecular heparin can be administered more conveniently and does not require laboratory coagulation monitoring. Systematic reviews and observational studies have demonstrated the efficacy and safety of low-molecular heparin in the treatment of VTE in pregnancy.
Warfarin is the most commonly used anticoagulant for the treatment of thrombosis, but because it crosses the placental barrier and is prone to spontaneous abortion, congenital heart disease, growth retardation, and fetal warfarin syndrome, and the most affected period is the 6th to 12th week of gestation, anticoagulation should be used with caution during pregnancy. The embryonic teratogenicity of warfarin is often manifested by midface hypoplasia, punctate cartilage hypoplasia, scoliosis, shortening of the proximal limbs and fingers (toes).
The use of warfarin in the second and early third trimesters may cause cerebral hemorrhage and brain fracture in the fetus.
5.Will blood clot treatment cause bleeding?
Theoretically, bleeding does not occur when anticoagulant drugs are taken under medical supervision. Low molecular heparin can be measured according to the patient’s weight, and it is very important to choose the appropriate dosage form. Warfarin requires regular blood tests for coagulation indicators, and there is usually no bleeding in the range of INR2 to 3.
In the course of anticoagulation therapy, maternal skin and mucous membranes must be closely observed for bleeding spots, purple spots, the amount of malignant dew, and whether there is blood oozing from the caesarean section wound. If there are flaky red spots, increased malignant dew, obvious blood oozing from the wound, subcutaneous ecchymosis at the puncture and injection site, abnormal bleeding from the nose and gums, hematuria, black stool, especially if there is intracranial hemorrhage such as headache, vomiting, change in consciousness and pupil changes, the patient should immediately Stop the medication and go to the hospital for consultation.
6.How should a pregnant woman undergoing thrombosis treatment deliver?
For pregnant women on anticoagulation therapy, the delivery method is best decided by a multidisciplinary team including obstetricians, pediatricians, NICU and vascular surgeons. To avoid the risk of bleeding due to anticoagulants during delivery in patients with VTE in pregnancy, normal heparin or low molecular heparin administered twice daily subcutaneously should be discontinued 24 h before induction of labor or cesarean section, while patients given once daily subcutaneous low molecular heparin may be given 50% of the dose on the morning of delivery.
If there is no persistent bleeding 12 h after delivery, restart low molecular heparin therapy. if general anesthesia is used, low molecular heparin should be restarted no earlier than 24 h after surgery. the duration of low molecular heparin or warfarin therapy after delivery should be at least 6 weeks.
7. Dosing during lactation?
Theoretically, neither warfarin nor low molecular heparin is secreted into breast milk, so breastfeeding during treatment is safe for the infant. Normal breastfeeding is beneficial to the development of the baby, while maintaining normal lactation of the mammary glands and reducing the chance of mastitis. Therefore, maternal patients with blood clots can breastfeed while on anticoagulation therapy.
8.Can I put a strainer in the lower extremity of maternal deep vein thrombosis?
Strainers are medically called inferior vena cava filters, which can prevent pulmonary embolism caused by dislodged DVT in the lower extremities. It needs to be done under the guidance of radiographic fluoroscopy, and radiation has teratogenic potential for fetal development. The placement of a filter is not recommended for pregnant women who wish to preserve their fetus. Experience with placement of inferior vena cava filters in pregnancy is very limited, and with the potential for increased risk of filter displacement and inferior vena cava perforation, this approach should be used only in pregnant patients with contraindications to anticoagulation or with recurrent pulmonary embolism despite adequate anticoagulation therapy given.
9.Can thrombolysis be performed for maternal deep vein thrombosis?
Thrombolysis includes intravenous thrombolysis and catheter thrombolysis. Catheter thrombolysis needs to be performed under the guidance of radiographic fluoroscopy, which has an impact on fetal development and may be teratogenic. Therefore, catheter thrombolysis should be avoided for pregnant women. Intravenous thrombolytic drugs may have an effect on the fetus, so try to avoid them. There is very limited experience with thrombolytic therapy given in patients with deep vein thrombosis in pregnancy, but it is likely to be life-saving in patients with large pulmonary emboli and severely hemodynamically compromised thrombosis in pregnancy.
Although thrombolytic therapy has the potential to result in abrupt placental separation, this complication has never been reported. Cesarean delivery and up to 10 days after delivery are considered relative contraindications to thrombolytic therapy, but successful thrombolytic therapy has been reported 1 hour after vaginal delivery and 12 hours after cesarean delivery.
10.How can maternal thrombosis be prevented?
In order to prevent thrombosis during pregnancy and delivery, we should prevent it in the following ways
①Assessment of risk factors for thrombosis through prenatal examination.
②Positioning and exercise: Pregnant women should change their position frequently and keep proper exercise, such as walking and proper straight leg raising exercises, to promote venous reflux in lower limbs.
③Diet: It is advisable to have a light, high-calorie, high dietary fiber, low-salt, low-fat diet, and drink more water to keep the bowels open.
④Clothing: wear loose underwear.
Health management during the puerperium
For normal delivery: elevate the lower limbs and encourage early movement out of bed; for cesarean delivery: in addition to medication for pain relief, perform voluntary activities in bed 6 hours after surgery; actively prevent thrombosis through early movement, appropriate body position and strengthening diet, so as to better protect maternal life safety and quality of life.
Pregnant patients with a previous history of thrombosis or a high risk of thrombosis should be given prophylactic doses of low molecular heparin. The media reported that movie star Xu Ruolu had to take 300 injections during her pregnancy because she needed subcutaneous injection of low-molecular heparin due to her high-risk factors of thrombosis, and finally delivered safely through effective prevention.
11.Treatment of deep vein thrombosis recovery period
①Adhere to regular, sufficient amount and full course of oral anticoagulant medication. Warfarin at the standard dose PT20-30 seconds, INR2-3, the international recommended course of treatment is six months to one year. Whether long-term anticoagulants are needed needs to be considered in the context of the disease, depending on what caused the thrombosis. If it is caused solely by pregnancy, childbirth and surgery, six months to one year of anticoagulation is usually sufficient after the trigger is removed.
Some patients need a comprehensive screening for thrombotic indicators to see if there are factors that predispose them to thrombosis, such as antiphospholipid antibody syndrome, protein C/S deficiency, and positive lupus antibodies, with which they need to be taken for a long time. In between, pay attention to check coagulation indexes and note any black stools, gum bleeding, etc.
②Adhere to wearing medical secondary compression elastic stockings: elastic stockings can relieve and reduce swelling of lower limbs, effectively prevent the recurrence of venous thrombosis in lower limbs and reduce the possibility of post-thrombotic syndrome because they can significantly improve the condition of venous blood flow stagnation in lower limbs and promote venous blood reflux.
③It is recommended to pay more attention to rest and appropriate exercise in general, and activity within half an hour is better.
④Take a light diet, drink more water, eat more green vegetables and fruits, and avoid spicy and stimulating foods.
12.How to prevent post-thrombotic syndrome?
Post-thrombotic syndrome (PTS), which is a chronic venous insufficiency secondary to impaired deep vein valve function after thrombosis, usually occurs 1~2 years after deep vein thrombosis, with typical symptoms including pain, sinking, swelling, cramping and edema of the affected limb. The typical symptoms include pain, itching and edema of the affected limb, capillary dilation in the ankle or larger area, hyperpigmentation of the skin in the foot and boot area, stasis dermatitis, and in severe cases, chronic and untreated venous ulcers.
In addition, secondary varicose veins may also develop. Post-thrombotic syndrome can occur in about 50% of patients with acute DVT within 2 years, and severe post-thrombotic syndrome such as venous ulcers can occur in 5%-10% of patients, which can seriously affect the quality of life. Thrombosis in the thigh and above, obesity, and advanced age are high risk factors for developing PTS. Patients whose lower extremity symptoms do not completely resolve within 1 month after acute lower extremity deep vein thrombosis are prone to post-thrombotic syndrome. Oral warfarin anticoagulation therapy may increase the risk of post-thrombotic syndrome if the INR does not meet therapeutic criteria.
Elastic medical stockings with a secondary pressure gradient may reduce venous hypertension, reduce edema, and improve tissue microcirculation. Several clinical trials have demonstrated the effectiveness of long-term use of medical compression stockings for the prevention of post-thrombotic syndrome. The American College of Chest Physicians (ACCP) guidelines recommend wearing secondary compression stockings for at least 2 years for patients with acute symptomatic proximal DVT, or longer if the patient has developed PTS symptoms. There is evidence that intravenous active medications such as Myzolyn, Desoxaparin, and Diosmin tablets may reduce the symptoms of PTS.
In conclusion, maternal DVT is not a terrible thing, but timely detection and proper treatment can preserve the fetus and cure the thrombosis without sequelae. For pregnant women who are at high risk of thrombosis, appropriate preventive measures can be taken to effectively avoid thrombosis.