Calcium Supplementation in Pregnancy

Calcium supplementation before and early in pregnancy may help prevent blood pressure disorders, such as pre-eclampsia, a new study suggests.

Pre-eclampsia is a condition characterized by high blood pressure during pregnancy along with protein in the urine. It can cause serious complications for the mother and baby. Pre-eclampsia can decrease the supply of blood and oxygen available to the mother and developing child. This may result in conditions such as a lower birth weight and neurological (nervous system) damage. The mother is at risk for kidney problems, seizures, strokes, breathing problems and even death, in rare instances. The cause of pre-eclampsia is not known. Pre-eclampsia usually occurs during the second half of the pregnancy and affects about five percent of pregnant women.

Researchers from South Africa explained that calcium supplementation during pregnancy may reduce the risk of hypertensive (blood pressure) disorders of pregnancy. For their review, they searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Central Register of Controlled Trials (March 2006) and chose randomized trials comparing at least one gram of calcium daily during pregnancy with placebo. Eligibility and trial quality were assessed. Data were extracted and analyzed using Review Manager software.

Twelve studies (15,528 women) were included. The researchers reported that most women were at low risk and had low dietary calcium. The study found that high blood pressure was reduced with calcium supplementation rather than placebo in 11 trials involving a total of 14,946 women. Pre-eclampsia was reduced in 12 trials involving a total of 15,206 women.

The effect was greatest for women at high risk, as evidenced in five trials including 587 women. The effect was also significant in women with low baseline calcium intake, as seen in seven trials involving 10,154 women.

Researchers noted that there was variability, with less effect in the larger trials. The composite outcome maternal death or serious morbidity was reduced. The syndrome of hemolysis (excessive breakdown of red blood cells), elevated liver enzymes and low platelets was increased. There was no overall effect on the risk of preterm birth or stillbirth or death before discharge from the hospital.

The study authors concluded that calcium supplementation appears to reduce the risk of pre-eclampsia and to reduce the rare occurrence of the composite outcome, “maternal death or serious morbidity.” There were no other clear benefits or harms.

The researchers also suggested that adequate dietary calcium before and during early pregnancy may be needed to prevent the underlying pathology responsible for pre-eclampsia. Additionally, the research agenda should be redirected towards calcium supplementation at a community level.

Integrative therapies with strong or good scientific evidence in the prevention and/or treatment of pre-eclampsia and related conditions include omega-3 fatty acids, fish oil, alpha-linolenic acid, coenzyme Q10, hibiscus, Qi gong, stevia and yoga.

For more information about integrative therapies for pre-eclampsia, please visit Natural Standard’s Foods, Herbs & Supplements and Health & Wellness databases.

Comments

[Leigh]

Is Calcium included in most prenatal vitamins?

[Joel M. Kauffman]

In this news item as well the ones above it, results of trials are not given in a meaningful form. We need the absolute % of subjects with the given endpoint, or the frequency (1 in 10 vs 1 in 25). See Calculated Risk by Gerd Gigerenzer. Or my book, Malignant Medical Myths.

It has been known for 30 years or more that the key nutrient deficiency in eclampsia is magnesium ion. Look up works by Mildred Seelig, MD. (Or in MMM.) Supplementing calcium in the absence of magnesium will make things worse.

[Daryn]

If magnesium was known to prevent pre-eclampsia, then why did they spend all of that time on calcium? Seems like a waste of resources.

[D. Scully]

Is this study ethical? Lots of people enroll in clinical trials because it is their only way to get healthcare, however transient. It seems very irresponsible for researchers to continue not giving calcium to high-risk mothers when they and the fetus are at risk for serious side effects.

Legal residents of the United States can sometimes get free or reduced-cost medical care if they are pregnant, but let’s be honest - many pregnant women in the United States can’t qualify for this type of care, and can’t afford it otherwise. This study makes me worry that there is a back door of doing clinical research by withholding a treatment that may help underprivileged women who are pulling at strings to keep themselves healthy during pregnancy.

[Emma]

I would like to know the statistics on the significance of side effects listed (increase in cases of hemolysis, elevated liver enzymes and low platelets) and how serious each of these conditions may be. I wouldn't want to put myself at a high risk for one of those disorders to potentially prevent a condition that effects only 5% of pregnant women.

[dalz]

Does a prenatal vitamin have enough Ca in it to coincide with this benefit?

[B. Page]

Is it possible to take too much calcium during pregnancy? Are there any other recent studies on what women can do to have safe and healthy pregnancies?

[veronica]

I was thinking along the same lines as B. Page. I wonder whether you can overdo the supplements. Also, if you take calcium and magnesium during pregnancy, does it cause any serious side effects from the interaction?

[Josh]

I know someone who had this condition, and it was very scary. I think moms need to have more information available to them about supplements to take and things to be careful of during their pregnancy. The person I knew didn't realize that this could happen to her since she was always healthy and followed all the rules during her pregnancy.

[Leigh]

Calcium can cause constipation, which can be a problem in pregnant mothers, especially since some may experience this already. This may pose a problem, as some medications available over the counter for constipation shouldn't be used during pregnancy.

[Water Point]

I bet women put a lot of stress on their spine during the pregnancy. I’ve heard that women should take this supplement to prevent osteoporosis throughout their lives. Are women at a risk of experiencing small fractures or fissures in their bones because of the added strain of the baby? Would calcium help with this?

[Rilo]

The study noted women who had a low dietary intake of calcium. How at risk are women who get sufficient amounts of calcium through their diet? Is this enough?

[CR]

I agree with Emma, it would be nice to see the statistics on the mentioned side effects. It would give one a much better picture to rate the risks and benefits of using calcium.

Aren’t pregnant mothers supposed to increase calcium and dairy (if not lactose intolerant) in the diet with healthy sources such as low-fat milk? Would a woman who does this get enough calcium to prevent pre-eclampsia?

[Benson]

This study is about preventing the occurrence of pre-eclampsia. Does anyone know how it is usually managed when it occurs? Is it usually reversible?