The National Women's Health Information Center encourages all pregnant women to take a prenatal vitamin. Prenatal vitamins tend to be quite potent since they are full of vitamins and minerals needed for the prenatal period. Prenatal vitamins are typically large and the dose high. Due to this, side effects may occur. Some women may experience all, some or no side effects. Becoming aware of the side effects of prenatals can assist with potential solutions for dealing with the effects if they occur.
Nausea
Nausea is the body's response to an unknown or potentially harmful substance that has entered the body. Prenatal vitamins are highly concentrated nutrients and the body may see them as a potential threat for people which can cause nausea. Nausea can feel uncomfortable and can cause a decrease in the use of prenatals. Consuming these vitamins with food, water or at bedtime may help you to relieve symptoms.
Heartburn
Heartburn is another possible side effect of prenatal vitamins. Pregnancy hormones cause the muscles in the esophagus and stomach to relax which can result in heartburn. This means that the likelihood of getting heartburn can increase especially in the second and third trimester according to the March of Dimes. During this time, anything can give you heartburn, even prenatals and other medications. Drinking plenty of water, consuming six small mini meals and following a low fat diet can help to alleviate the symptoms of heartburn, suggests the March of Dimes.
Headache
Headaches are a common side effect during pregnancy due to hormones. However, if starting a prenatal for the first time, the body may respond with a headache. One or two headaches at the initial start of taking a prenatal is reasonable. If the headaches persist, however, then discuss it with your doctor.



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