While most expectant mothers understand the need for and benefits of taking prenatal vitamins, there can be some side effects from these vitamins that work against this. These are primarily centered around digestive system complaints. Let’s discuss the most common of these, along with ways to deal with them.

Having a tablet or capsule that is hard to swallow will slow down even the most conscientious mother-to-be. Single piece, once-a-day prenatal vitamins containing DHA are notorious for being large and hard to swallow. This is mainly due to the presence of DHA, which requires quite a bit of volume. Plant-based DHA can be particularly troublesome in this regard, as it is more difficult to get to a more concentrated state (with less volume for a given amount) than with fish-based DHA. Many of the single piece DHA products try to include as much DHA as possible, with resultant size issues. The internationally accepted standard for DHA supplementation during pregnancy is 200 mg per day. Choosing a prenatal vitamin with 200 to 250 mg of well purified, fish-based DHA can help a lot with the size issue.

There are other factors that can also make prenatal vitamins hard to swallow. Tablet formulas often have enough friction that they don’t go down easily. Coating of tablets helps a lot in this regard. Many vitamin formulas have unpleasant odors and/or tastes that make them difficult to get down. Tablet coating can also help here. Capsules and softgels with durable shells that do not tend to leak or allow air passage that can result in DHA going rancid are less likely to have odor and taste issues.

Stomach irritation and nausea can be significant problems for pregnant women, who often have nausea issues to begin with. Any multivitamin formula can generate stomach irritation and nausea, even without underlying “morning sickness.” Taking multivitamins on an empty stomach often makes these problems worse, so it is advisable to take any multivitamin, including prenatals, after meals.

There is a potential nausea problem associated with DHA-containing prenatals that is known as “burp back” or “fishy burp.” This occurs when the DHA has gotten rancid (oxidized). Oxidized DHA, even plant-source DHA, will have a fishy taste and smell that can be very unpleasant. It also irritates the stomach and causes burping, carrying the fishy odor and taste to the mouth, which invariably leads to nausea and distress. Choosing a DHA-containing prenatal with highly purified DHA and a durable shell will typically eliminate this problem.

Constipation is a common problem for pregnant women. It can be worsened by prenatal vitamins, all of which contain a significant amount of iron, which often promotes more constipation. A number of the better prenatal vitamin products are now incorporating the stool softener docusate sodium to help reduce problems with constipation.

A side effect not involving the digestive system that can occur with prenatal vitamins is the so-called “niacin flush.” This is redness, warmth, and itching in the skin that can occur in some people after consumption of niacin, vitamin B3. Most good prenatal formulas contain this vitamin. Fortunately there are some “non-flush” forms of niacin that can virtually eliminate this problem. If you have experienced this issue in the past, or you begin to experience it when starting a prenatal vitamin, look for another formula that contains the non-flush form of niacin.

Most Obstetricians have a variety of prenatal vitamin samples, and many of them will give you several different ones to try so you can see which you prefer. Keep the side effects we have covered in mind, and choose the one that works best for you.