Oral Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2015

Bone safety and prolonged use of lmwh during pregnancy (#3)

Päivi J. Galambosi 1 , Risto Kaaja 2
  1. Obstetrics and Gynaecology, Helsinki University Hospital, Helsinki
  2. Turku University Hospital, Turku, Finland

It is uncertain whether long-term low-molecular-weight heparin (LMWH) decreases bone mineral density. The aim of the study was to determine whether prolonged and high dose use of dalteparin or enoxaparin during pregnancies leads to persistent loss of bone mineral density (BMD).

BMD was measured using dual-energy X-ray absorptiometry (DEXA) in women, who received long-term and/or high-dose LMWH during pregnancies (n=92), compared to women without any use of LMWH (n=60) on average 5 years (range 1-12 years) after the delivery. Every women also filled a questionnaire with basic characteristics and several questions related to osteoporosis risk factors.

BMD in spine was significantly lower in the intervention group than in the control group (1.22 g/cm2 vs. 1.27 g/cm2, p=0.017), but no difference existed in femoral neck (0.99 g/cm2 vs. 1.01 g/cm2 , p= 0.473). Anyhow no correlation between BMD and dose, duration nor type of the LMWH, and age of women existed. Changes in BMD were not explained by age at menarche, Calsium-intake, physical activity, smoking, alcohol use, duration of the lactation. Strong positive correlation with BMD and body mass index existed. BMD also correlated positively with the duration of combined contraception pill use. The controls have used combined contraception pills significantly longer than the intervention group, because of the high risk of thrombosis in the intervention group. Although BMD in spine was higher in the control group than in the intervention group it did not appear to be related to LMWH-use, but was explained by higher body mass index and longer combined contraception in the control group.

We conclude that LMWH even with prolonged use seems to be safe with regard to bone health.