Outcomes in Pregnant Women Exposed to Low Molecular Weight Heparin.

To evaluate the efficacy of low molecular weight heparin (LMWH) in a heterogeneous population of pregnant women.

Using hospital databases, we retrospectively evaluated the records of all women who were managed with LMWH during pregnancy and referred to our hematology clinic at a tertiary center between January 2001 and August 2009. Data collected included age, rate of live births, indications for using LMWH, type of thrombophilia, need to adjust LMWH dose, incidence of adverse outcomes of pregnancy (AOP), maternal complications, and complications related to use of LMWH.

There were a total of 64 pregnancies in 57 women whose mean age was 25 years (range, 23 to 48). The rate of live births was 97%. Indications for LMWH included: deep venous thrombosis (DVT) (n=11), pulmonary embolism (PE) (n=10), combined DVT and PE (n=5), cerebrovascular accident (n=7), prosthetic mechanical heart valves (n=1), and upper extremity arterial thrombosis (n=1). Of the 57 women, 7 had a history of intrauterine growth restriction (IUGR), 6 had a history of preeclampsia, 3 had a history of HELLP syndrome and 1 had a history of placental abruption. In 31 of the pregnancies women had a prior history of spontaneous pregnancy loss (23 recurrent first trimester losses, 5 second trimester and 3 stillborn). There were 7 women with history of unexplained infertility. Seventeen women had factor V Leiden, 15 had prothrombin G20210 mutation, 11 had antiphospholipid antibodies IgG isotype, 8 had IgM isotype, 5 had lupus anticoagulant (LAC), 3 had hereditary antithrombin (AT) deficiency, and 1 protein S deficiency. Twenty women had less important thrombophilias. 14 pregnancies (22%) were managed with treatment doses of LMWH while 50 pregnancies (78%) were managed with preventive doses. LMWH dose adjustment was required in 11 pregnancies on treatment doses and in 23 pregnancies on preventive doses. Six pregnancies were complicated with IUGR and 3 with other complications (diaphragmatic hernia, congenital heart defect and death). Six women had documented bone loss and 1 had an allergic reaction. 15 had other complications (4 hypertension, 2 anemia, 1 subchorionic hematoma, 1 preterm labor, 1 proteinuria, 1 preeclampsia, 1 cholecystitis, 1 transient visual loss, 1 headaches 1 was diagnosed of breast cancer after completion of the post-partum period and 1 had amniotic fluid leak after amniocentesis. 14 pregnancies (22%) were managed with treatment doses of LMWH while 50 pregnancies (78%) were managed with preventive doses. LMWH dose adjustment was required in 11 pregnancies on treatment doses and in 23 pregnancies on preventive doses. Six pregnancies were complicated with IUGR and 3 with other complications (diaphragmatic hernia, congenital heart defect and death). Six women had documented bone loss and 1 had an allergic reaction. 15 had other complications (4 hypertension, 2 anemia, 1 subchorionic hematoma, 1 preterm labor, 1 proteinuria, 1 preeclampsia, 1 cholecystitis, 1 transient visual loss, 1 headaches 1 was diagnosed of breast cancer after completion of the post-partum period and 1 had amniotic fluid leak after amniocentesis.

Almost all pregnant women exposed to LMWH in our series had live births. Dose adjustments in LMWH were required for both treatment and prophylactic dosages. Complications related to use of LMWH were minimal.

No relevant conflicts of interest to declare.