Health researchers have looked into the evidence, finding that use of some supplements during pregnancy may be unnecessary and not completely without harm
Health researchers from the University of Adelaide have analysed three decades’ worth of research on the use of supplements in pregnancy, looking at the impact of folic acid, vitamin B12, vitamin D, calcium, zinc, iron, selenium and iodine supplementation on pregnancy outcomes.
They concluded that while folic acid and iodine are recommended for routine supplementation in order to reduce risk of developing major congenital malformations and support foetal neurodevelopment, supplementation of other vitamins and minerals is largely dependent on a woman’s abilities to meet recommended dietary intakes.
Although multivitamin use is common in pregnancy, there is actually a lack of data supporting their widespread use, the researchers argued in their review published in the SHPA’s Journal of Pharmacy Practice and Research.
Lead review author Professor Claire Roberts said the requirements differ depending on the circumstances of each women.
“While routine supplementation of folic acid is well-founded and remains important, supplementation with calcium, zinc and selenium appears to reduce some pregnancy risk factors to varying degrees, while supplementation with vitamin B12, vitamin D and iron is heavily dependent on individual diet and lifestyle,” said Professor Roberts.
“There were also discrepancies across the board in the makeup of four heavily marketed multivitamins and the general recommendations regarding vitamin and mineral supplementation that have been made by the National Health and Medical Research Council (NHMRC) and the Royal Australian and New Zealand College of Obstetricians and Gynaecologists.”
In many cases, supplementation with such multivitamins may provide amounts of various vitamins and minerals above what is actually needed, and this may not be completely without harm, said the authors.
For example, vitamin C supplementation alone does not appear to be beneficial, and vitamin C combined with vitamin E from 12-18 weeks’ gestation has been shown to increase risk of foetal loss or perinatal death.
In addition vitamin A is a teratogen, with high intake during pregnancy being associated with increased risk of congenital malformations.
The authors recommend “caution” regarding widespread routine supplementation practices, adding that pharmacists should be aware of special considerations and be prepared to provide balance and up-to-date information to women.
In a related editorial, Dr Debra Kennedy, Clinical Geneticist from the Royal Hospital for Women in NSW, flagged concerns that more Australian women are avoiding carbohydrates for weight control reasons and gluten-containing foods for non-specific ‘health’ reasons, depriving them of dietary balance.
“It is concerning that some women take excessive amounts of certain vitamins with no real evidence of need or safety, yet with potential risk of harm – there is a general perception that if something is good, then more of something good must be even better,” said Dr Kennedy.
“Unfortunately this does not always apply to vitamins, high or mega doses of which may not always be as benign as everyone would like to believe.”
Dr Luke Grzeskowiak, Chair of SHPA’s Women’s and Newborn Health Specialty Practice stream, said the research highlights that advice regarding supplementation during pregnancy requires and individualised approach and ideally the involvement of a pharmacist.
“This review highlights that, as medicines experts, pharmacists are well-positioned to identify a woman’s individual requirements and factor in other medicines they may be taking, in advising the most appropriate treatment options,” he said.
“For women who have a particularly unhealthy diet or who struggle to eat well due to severe morning sickness, the additional nutrients may be useful. However, for the majority of women, complex multivitamin preparations represent an unnecessary added expense.”