Osteopenia in pregnancy during long-term heparin treatment: a radiological study post partum.

Osteopenia, sometimes with compression fractures of the spine, is a side-effect of long-term heparin treatment. The frequency is unknown. In this study, 70 women were given subcutaneous heparin as therapy for, or prophylaxis against, thromboembolism during pregnancy. All, except two, were examined by X-ray of the spine and hip first week post partum. The duration of treatment and the dosage of heparin varied. There were 12 (17%) with obvious osteopenia, including two women with multiple fractures of the spine (3%). Re-examination 6-12 months post partum showed that the changes were reversible in most cases. Another 18 women were examined about three years after heparin treatment during pregnancy. No obvious osteopenia was found among them or in a control group of 30 women examined in the first week post partum. The degree of osteopenia was not correlated with either the heparin dose or the duration of treatment. Women treated with heparin in consecutive pregnancies do not seem to have an increased risk of osteopenia.