Prospective observational study of bone mineral density during pregnancy: low molecular weight heparin versus control.
BACKGROUND
The aim of this study was to assess the effect of long-term low molecular weight heparin (LMWH) on bone mineral density (BMD) during pregnancy.


METHODS
Fifty-five patients with recurrent miscarriage and known thrombophilia (antiphospholipid syndrome) were followed through pregnancy in an ethically approved prospective observational study. All women had dual energy X-ray absorptiometry (DEXA) scans at the lumbar spine (L1-L4) performed within 6 months prior to conception and in the immediate post-natal period, within 6 weeks of delivery. LMWH (5000 U/day) plus low-dose aspirin was commenced after a positive urine pregnancy test and continued throughout pregnancy and after delivery until 6 weeks post-partum. A group of 20 volunteers with recurrent miscarriage, not requiring any treatment intervention, acted as controls and were monitored in an identical fashion.


RESULTS
Characteristics were not significantly different between treated patients and controls. Both groups showed a similar loss in lumbar spine (L1-L4) BMD by the end of the pregnancy [LMWH 4.17% or 0.045 g/cm(3), 95% confidence interval (CI) 0.036-0.062 versus control 3.56% or 0.043 g/cm(3), 95% CI 0.027-0.059]. However, the difference in bone loss between the groups was not statistically significant (0.002 g/cm(3), CI -0.0124 to 0.00865; P = 0.88). No patient suffered vertebral fracture.


CONCLUSIONS
Bone loss associated with the use of long-term LMWH is not significantly different from physiological losses during pregnancy.
Carlin
A J
AJ
Department of Obstetrics and Gynaecology, Liverpool Women's Hospital, Crown Street, Liverpool L8 7SS, UK.
Farquharson
R G
RG
Quenby
S M
SM
Topping
J
J
Fraser
W D
WD
D015502:Absorptiometry, Photon; D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage*; D015519:Bone Density / Q000187:drug effects*; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000188:drug therapy* / Q000517:prevention & control*; D011446:Prospective Studies
D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight