Prenatal Vitamins 101: How They Work and How to Choose the Right One

Prenatal vitamins are recommended to women in order to assure healthy embryonic development. However, the vast selection of brands and endless varieties of pills can make it hard to pick the best one. Adding to the ambiguity is that the effectiveness of certain vitamins is tied to lifestyle factors such as weight, exercise, and quality of nutrition. There are some things to keep in mind as you decide which vitamins you need. This article will cover the scientific reasoning for why prenatal vitamins are essential, and how to optimize the effects of taking them by choosing the right ones.

Do I need to take prenatal vitamins?

While a healthy diet will help you to get most of your essential vitamins and minerals, vitamins may help fill in any essential gaps. Vitamins for pregnancy may help prevent potential complications. For example, folic acid may help to prevent neural tube defects and iron may protect you from developing anemia and helps to support the baby’s development (Mayo Clinic)

What are prenatal vitamins?

If you decide to take prenatal vitamins, it’s important to understand what they are, and how they are beneficial. Vitamins are nutrients that the body cannot produce on its own but are vital for healthy function. This means that if you don’t get enough vitamins in your diet, supplements can help you reach your target intake.

During pregnancy, the body has a higher demand for nutrition, which can be challenging for women with certain food allergies, dietary restrictions, or morning sickness. It’s a good idea to take supplements in order to prepare your body for conception and pregnancy.

Prenatal vitamins are multivitamins that contain a variety of nutrients and minerals. The Mayo Clinic states that you should look for a vitamin that contains folic acid, vitamin D, calcium, and iron at the minimum. These are the essential prenatal vitamins, and each plays a role in healthy pregnancy development. Zinc, copper, iodine, DHA, vitamin A, vitamin C, and vitamin E could also be beneficial (Mayo Clinic).

How do they work?

Prenatal vitamins work by supplying nutrients critical to various stages of development, from implantation to delivery.

Pregnancies develop in stages, evolving from a single fertilized egg (zygote), to a blastocyst (a hollow ball of cells), to an embryo, and finally a fetus. During the embryonic stage, most of the organs are in development. The embryo begins to elongate and starts to resemble a human shape. Shortly after elongation, the area which will eventually become the brain and spinal cord begins to develop. This process is called neurulation, or development of the neural tube (Biologists.org).

Folic acid, also known as vitamin B9, is in higher demand during these developmental phases. It is critical for DNA replication and is also involved in enzymatic reactions that mediate vitamin metabolization and amino acid synthesis. Studies have repeatedly shown that dietary supplementation of folic acid highly reduces incidence of neural tube defects, such as spinal bifida (Greenberg, MD 2011).

Iron deficiency can have a variety of effects, depending on the stage at which a mother is anemic. It is important to note that iron supplementation is a delicate balance; taking too much of it is harmful. A study published in The Journal of Nutrition followed 44,000 women who sought prenatal care before 24 weeks of pregnancy, and found that maternal anemia diagnosed before mid-pregnancy was correlated with a higher rate preterm births (Scholl 2000). Further studies have linked iron deficiency to low birth weight and postpartum hemorrhages (Allen LH 2000). Ensuring proper iron levels before conception is a great preventive measure to avoid the chance of such outcomes.

What are things to look for when choosing the right prenatal vitamin?

The FDA does not regulate any vitamins. Vitamins are meant to be used in conjunction with a nutritious diet, so they are not drug treatments. Therefore, they are classified as “food” and not “drugs.” This means that prenatal vitamins do not have to go through the same regulatory processes as medicines, and places the responsibility for integrity on the companies that manufacture them (FDA.gov).

The NIH Office of Dietary Supplements suggests looking on the label for approval from U.S. Pharmacopoeia, NSF International, or ConsumerLab.com (NIH.gov 2011).


This means that the supplement has been tested for harmful ingredients, proper manufacturing, and a full ingredients list. Keep in mind, though, that this does not guarantee safety. It is important to go with a brand that you know and trust.

Keep an eye out of the % DV on the back of the bottle. Vitamins should contain a maximum of 100% DV, as any more than that may cause a vitamin overdose (ConsumerLab.com). Make sure to talk with your doctor before starting a new vitamin.

While prenatal vitamins are all formulated differently, it is a good rule of thumb to look for Vitamin D, Calcium, Folate (or Folic Acid), and Iron.