Pregnancy associated osteoporosis

Previous literature reports have suggested that osteoporosis associated with pregnancy is a rare event. We have examined the prevalence of this condition and compiled data on the largest group of such patients in the literature.

With the help of the National Osteoporosis Society 35 women with pregnancy associated osteoporosis were identified. These women were matched with a control group from our already established computer data bank for age, weight, height and calcium status. Detailed questionnaires were sent to the osteoporotic sufferers enquiring about their present condition, past medical and drug history, and their menstrual, lactational and obstetric histories. They were also asked to complete a detailed dietary history to establish their calcium status. A questionnaire was also completed by the parents of these women and the parents of the control group, asking specifically about fracture history.

Twenty-nine women had idiopathic osteoporosis associated with pregnancy, while in six, the condition may have resulted from drug therapy or associated diseases. Pain occurring late in the first full term pregnancy was the most common presentation. The natural history was for the condition to improve with time. There was a significantly higher prevalence of adult related fractures (P < 0.02) occurring at an earlier age in the mothers of these women compared to a control population.

We have identified 35 women who have developed osteoporosis during or shortly after pregnancy and in only six of them could a recognized underlying cause be suggested. These findings would suggest that idiopathic osteoporosis associated with pregnancy may be more common than the current literature suggests. The higher prevalence of fractures in the mothers of our population compared to controls raises the question of a possible associated genetic factor in the aetiology of this condition.