We all know that pregnancy uses up a woman's stores of minerals. The old saying, "a tooth for every baby" says how much a growing fetus can take from a mother. Iron stores, calcium, vitamin D, zinc, etc can all be depleted during pregnancy and whether this loss of minerals, has a role to play in the development of peripartum cardiomyopathy is something that needs to be investigated.
There are many books and studies on Vitamin D 's role in the body. Low vitamin D, leads to low calcium and calcium is necessary for a strong heart. At a time, when a mother's blood volume is increasing by 50%, the heart needs to be strong and low vitamin D could lead to a weakened heart. It is also well known that dark skinned people require more sun exposure to get the same amount of vitamin D, than fair skinned people. Vitamin D is synthesized by the skin when it is exposed to the sun. Studies show that dark skin may require six times the exposure to produce the same amount of vitamin D as fair skin. Could this be one of the reasons, why PPCM is more prevalent among dark skinned people?
Vitamin D has been studied and found to improve blood pressure. http://www.telegraph.co.uk/health/healthnews/9226088/Vitamin-D-as-good-as-drugs-at-reducing-high-blood-pressure.html
Dilated cardiomyopathy as a first sign of nutritional vitamin D deficiency rickets in infancy
A five-month-old boy presented with severe dilated cardiomyopathy, requiring intravenous inotropes as part of the initial management. He was found to have hypocalcemia due to vitamin D deficiency rickets. His cardiac function recovered completely after six months of vitamin D supplementation. Source ( http://www.ncbi.nlm.nih.gov/pubmed/10375722 )
Vitamin D, sun exposure, supplementation and doses , discusses how to increase your vitamin D.
Vitamin D toxicity through supplementation is unusual. If in doubt blood tests can determine vitamin D levels but a safe way to obtain vitamin D is through adequate sunshine. Unfortunately, sunshine is not often enough especially when vitamin D stores are already low and supplementation may be answer to raising vitamin D levels.
Personally, I had low vitamin D in my PPCM pregnancy, whether or not vitamin D supplementation and sunshine helped me recover, will never be proven but I truly believe vitamin D had a role to play in PPCM for me, both in development and recovery. My GP continues to watch my vitamin D levels, which still have room for improvement.