Pregnancy Related Osteoporosis

This is a rare condition where bones become fragile and break easily either during pregnancy or after pregnancy. Painful fractures can occur in the spine or occasionally the hip. It is a condition which probably goes undiagnosed in many cases. Women with the condition can find it very difficult to find information.

There is good news. Much is still not understood about the condition, but it is known that these broken bones heal normally, that most women make a full recovery, and that the condition does not recur with subsequent pregnancies. The National Osteoporosis Society in the UK have produced helpful literature.

Osteoporosis fractures related to pregnancy occur usually during or after first pregnancy. They occur at the time of giving birth or up to 8 to 12 weeks following pregnancy and can bring acute pain. There are specific exercises recommended that will help recovery (again, for more information see NOS UK).

It is known that bones lose density during pregnancy and lactation but this occurs with all women and the body naturally regulates itself to ensure that mother and baby have an adequate supply of vitamins and minerals. Breastfeeding is discouraged by most doctors for women with this condition but the NOS advices: “ This is a difficult decision…There also is no clear evidence that, if you breastfeed, broken bones take longer to heal or that further fractures will occur. If this issue is very important to you, then you may decide to breastfeed for as long as you feel comfortable.”

Sometimes women are offered medication to treat the condition, in particular bisphosphonates like pamidronate or zolendronate. Because the body recovers quite quickly by itself and because these drugs have not been proven to be safe or effective in younger women, their application is definitely questionable. These are drugs that stay in the bones for a long time and effects on a baby in the womb in future pregnancies are not known.

Advice from U.S. osteoporosis expert Dr Susan Ott:

Women who are pregnant should not take bisphosphonates. If women are already taking a bisphosphonate and want to become pregnant, it is not clear how long they should wait. Until more information is available, I suggest waiting at least one year after stopping the medication to try getting pregnant. If a woman is taking a bisphosphonate and inadvertantly gets pregnant and wants to continue the pregnancy, she should be carefully followed, with measurements of calcium and optimal vitamin D levels. Calcitonin is a safe drug to use during pregnancy if bone loss is a concern. Young women should not be getting bisphosphonates anyway unless they definitely have established osteoporosis (that means they have non-traumatic fractures) and other methods are not working. Osteopenia in a healthy woman is not an indication for any bisphosphonate!

This from the 2004 FDA label information for pamidronate:

Although there are no data on fetal risk in humans, bisphosphonates do cause fetal harm in animals, and animal data suggest that uptake of bisphosphonates into fetal bone is greater than into maternal bone. Therefore, there is a theoretical risk of fetal harm (e.g., skeletal and other abnormalities) if a woman becomes pregnant after completing a course of bisphosphonate therapy. It is not known whether Aredia (pamidronate) is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Aredia is administered to a nursing woman.