Many pregnant women take the wrong dose of micronutrients

February 14, 2011

A German study has shown that many pregnant women and their doctors are unsure of reasonable intake of food supplements, despite existing recommendations.

In the study conducted at three German clinics, nutritional scientists studied and assessed the intake of food supplements prior to and during pregnancy (1). A total of 522 puerperal women were systematically surveyed in the first three days after giving birth. The study revealed that 97 percent of those questioned took at least one food supplement during pregnancy, and nearly two-thirds had even done so prior to becoming pregnant. However, within the group surveyed the amounts varied enormously: the intake of folic acid ranged from between 0.2 and 5 mg per day, in the case of iron supplements the figure even ranged between 4 and 600 mg a day. Age, education, ethnic background and number of previous pregnancies all had little impact on the general behavior of the women toward the use of supplements. One positive finding, however, was that over 40 percent of those questioned stated their gynecologist as the most important source of information when it came to health supplements.

The findings provide food for thought: according to the scientists, although over 85 percent of the women took folic acid in the first three months of pregnancy, which can help prevent neural tube defects in fetuses, only a good third of those had actually followed advice and started with a 0.4 mg course of daily supplements at least four weeks prior to becoming pregnant. In many cases the intake thus occurred too late – and, in addition, was then quite often dosed too highly (8 percent of the women), something which can conceal a vitamin B12 deficiency. In the case of iodine, by contrast, the researchers were able to allay fears: the trace element that is important for the brain development of the fetus was already consumed by a quarter of those surveyed before pregnancy, while during pregnancy that figure even rose to nearly four-fifths.

By comparison, supplementation of iron – essential for the supply of oxygen to the fetus – appeared too high. According to the scientists, around two-thirds of the women in the group studied took iron supplements, despite the fact that only around a third of them actually suffered from iron deficiency. In addition, results showed that three-quarters of the pregnant women deliberately took magnesium supplements, which is only recommended by doctors in individual cases, while over 40 percent took omega-3 fatty acids which can contribute to the development of cognitive abilities.


  1. Becker S. et al. Verwendung von Nährstoffsupplementen vor und während der Schwangerschaft. Ernährungsumschau. 2011; 1:36-41.