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What Are the Side Effects of Prenatal Vitamins?

It is quite common for women to take prenatal vitamins during pregnancy or when breastfeeding their babies.

However, most women who take these over-the-counter prenatal vitamins are unaware of the side effects that may occur because of them.

It is true that you can’t deny the importance of these vitamins. Ms. Robin Elise Weiss rightfully points out that prenatal vitamins are integral for sustaining a pregnancy and ensuring that your unborn child develops at the required rate.

However, it is equally important for the masses to be aware of the possible consequences of taking these over-the-counter prenatal vitamins.

Constipation and Diarrhea

Ask any doctor, and they will tell you that when a woman is pregnant, one of the key things that her body needs is iron. This is because iron aids in the development of hemoglobin, which then ensures that the optimum amount of oxygen reaches the baby and placenta.

As mentioned by Sheyna E. Gifford on Dignity Health, one of the key ingredients in prenatal vitamins is iron. The required amount of iron for a pregnant lady is considered to be 27 milligrams. However, most over-the-counter prenatal vitamins contain up to 30 mg of iron.

While the body requires iron, too much of it tends to cause bowel problems, ranging from constipation to diarrhea. According to WebMD, these side effects are not permanent and will disappear once your body gets used to the medications.

However, if the symptoms persist, it is best to consult a doctor or change your prenatal vitamins to one which features a smaller dose of iron.


According to Everyday Health, one of the common side effects of taking prenatal vitamins is the occurrences of migraines. Since feeling dizzy at times is a condition that occurs quite frequently during pregnancies and thereafter, it is not considered to be a major side effect.

However, if your headache keeps you up at night or it becomes too unbearable for you and renders you incapable of performing everyday tasks, it is time to curtail the use of over-the-counter prenatal vitamins and opt for medicines that your doctor provides you.

Nausea and Vomiting

Feeling nauseous during a pregnancy is nothing to be alarmed about. Instead, it is one of the earliest signs of pregnancy and serves to be quite common throughout the first trimester. Hence, nausea and vomiting may not always be a side effect of a given vitamin.

As per Jill Lee of Livestrong, there are cases where prenatal vitamins cause vomiting and nausea. It is easy to deal with feeling nauseous since it somewhat becomes a part of your life during the early days of your pregnancy.

However, when you find yourself puking every time you take a prenatal vitamin, you might be frustrated.

No one can claim that they enjoy vomiting. Therefore, if you undergo this side effect, you should take measures to combat it.

For example, one way to do so can be to take the vitamins just before going to bed or right after a meal. This act will allow your body to absorb the vitamin better than it would have had you taken the vitamins during the day without eating a meal.

For those of you who vomit right after taking the over-the-counter prenatal vitamins, it is best to follow these remedies.

This is because if you don’t do so and vomit the vitamin soon after taking it in, your body will not be able to benefit from it and the whole purpose of using such vitamins will not be achieved.

Allergic Reactions

Now, this side effect might be rare. However, this does not mean that it does not occur in those who take prenatal vitamins.

There is a chance that you might be allergic to some of the ingredients included in the vitamins, which might lead to an allergic reaction. Possible symptoms may include rashes, swelling and constant itching on the face and throat.

It is better to peruse the ingredients of the vitamins before you take them to avoid the development of this side effect.

Overdose Effects

Many people do not consult their doctors or midwives before taking prenatal vitamins. This is because the advantages of these medicines are widely known, and they are available over the counter at most drug stores.

The fact that you don’t need a prescription might make the act of finding prenatal vitamins quite easy, but it also means that people misuse it. Many use the vitamins without knowing about the proper dose and end up taking too much of it.

As you know, too much of anything is just as bad as too little of it. If you end up overdosing on prenatal vitamins, your body will start exhibiting various symptoms ranging from stomach pain, back ache and headache to bloody urine and joint pain.

The worst part is that these symptoms are just some of the issues you will face. Therefore, make sure you do not use the medicine without knowing about the proper dose.

Some over-the-counter prenatal vitamins contain a higher concentration of different ingredients than others. Only a professional can tell you which vitamin you and your child needs.


The fact that a few side effects mark prenatal vitamins does not mean that they do not pose any advantages. As Dr. Dina (from mentioned, it does lead to an array of benefits which include combatting congenital abnormalities in a child.

However, ensure that you do not misuse the vitamins and take them after learning about the proper dosage.

For those of you who start exhibiting any of the side effects at a severe rate, it is best to stop the use of the vitamins for the time being and consult a physician who will guide you on the proper course of action.

Provide your child with the best, but stay safe in the process of doing so.