Can there be side effects associated with prenatal multivitamins?

Updated on: Feb 22, 2016

Yes. The most common side effects associated with taking prenatal multivitamins are nausea and constipation. It is important not to stop taking the multivitamin, but rather to attempt solutions to slow down or resolve the associated symptoms.


The prenatal multivitamin is essential to meet all the needs of vitamins and extra minerals during pregnancy. For more information on what should be in a prenatal multivitamin, see the following article.


Under the effect of pregnancy hormones, digestion and intestinal movement (transit) is slowed, which can cause nausea and constipation. While taking a prenatal multivitamin may also cause these side effects, it is important not to stop taking it. A deficiency of certain nutrients can cause the following:





Iron Anemia Anemia
Vitamin B12 Anemia Anemia
Memory problems
Other neurological problems
Calcium and Vitamin D Osteoporosis Dental defects
Rickets (bone deformities)
Folic acid Neural tube defects (spina bifida)


It seems that women taking a prenatal multivitamin before conception were generally less nauseated and vomited less during pregnancy than women who had not taken it. On a more positive note, there are solutions available for pregnant women who experience symptoms associated with taking prenatal multivitamins:


If one multivitamin does not work for you, try another brand. Ultimately, if the solutions do not work, before you stop taking the prenatal multivitamin, consult a nutritionist or a doctor.


American College of Obstetricians and Gynecologists. (2015). Practice Bulletin No. 153: Nausea and Vomiting of Pregnancy. Obstetrics and gynecology, 126 (3), e12 – 24.

Kaiser, L. et Allen, L. H. (2008). Position of the American Dietetic Association: Nutrition and Lifestyle for a Healthy Pregnancy Outcome. Journal American Dietetic Association, 108(3), 553-61.

La société des Obstétriciens et gynécologues du Canada. (2006). L’acide folique pour la préconception et la grossesse.

Pfizer Consumer Healthcare. What is stresstabs®?

Santé Canada. (2009). Lignes directrices sur la nutrition pendant la grossesse à l’intention des professionnels de la santé.


Baby Center. (2015). Les multivitamines prénatales.

Baby center. (2015). Faut-il prendre des compléments alimentaires au cours de la grossesse ?

Doré N. et Le Henaff, D. (2015). Mieux vivre avec notre enfant de la grossesse à deux ans, guide pratique pour les mères et les pères.

Les diététistes du Canada. (2013). Vous envisagez de devenir enceinte?

Naître et grandir. (2012). Les vitamines et minéraux durant la grossesse.


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