Prenatal vitamins: Everything you need to know about supplements

    Updated 19 January 2023 |
    Published 23 December 2019
    Fact Checked
    Medically reviewed by Dr. Charlsie Celestine, Obstetrician and gynecologist, New Jersey, US
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    Not sure which prenatal vitamins you need in pregnancy? Here, two experts explain everything you need to know, including which nutrients to scan the label for.

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    You might have imagined that you’d be eating the most nutritious diet during pregnancy. However, the reality is that pregnancy sickness, fatigue, and unexpected cravings can make this really difficult, even if you’re trying your best. 

    But as your body changes and your baby grows, you need more of certain vitamins during pregnancy, which is where prenatal vitamins and other supplements come in. They can help you make sure you get what you both need. So which prenatal supplements for pregnancy should you buy?

    Your health care provider will be able to guide you through pregnancy, explain which supplements are okay to take, and may be able to help you find alternatives if you need them. They will assess the risks and benefits to help you decide what’s safe. Before you start taking any new vitamins, herbal remedies, and supplements, you should always speak to your medical professional. 

    We asked two Flo experts — registered dietitian Lauren Talbert and obstetrician-gynecologist (OB-GYN) Dr. Jenna Flanagan — to explain what you and your baby need as your pregnancy progresses and what to scan the label for. 

    What are prenatal vitamins and other supplements?

    While your health care provider has no doubt advised you against “eating for two,” your body goes through some pretty huge changes during pregnancy and you might have experienced new pregnancy cravings. Because of this, you have increased nutritional needs. You’re growing another person, after all. 

    During pregnancy, your body will prioritize your baby. This means that the baby will take any macronutrients (e.g., fats, proteins, and carbohydrates) and micronutrients (e.g., vitamins and minerals) that they need to develop from your reserves. Prenatal supplements can give you a boost of nutrients quickly and easily, so you don’t lose out (sometimes referred to as nutrient deficiencies). 

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    What are the best prenatal vitamins and other supplements?

    Unless your health care provider suggests otherwise, you don’t need to follow a special healthy pregnancy diet during pregnancy. However, prenatal supplements for pregnancy are specially designed to give pregnant women and people the nutrients and energy that they might need. 

    According to Talbert, the most common nutrients you want to look for are:

    • Iron
    • Folate
    • Calcium
    • Vitamin D
    • Omega-3

    Prenatal supplements generally contain most of these crucial nutrients, but you should always read the ingredients list and speak to your healthcare provider before starting a new vitamin or supplement. 

    Folic acid

    When you’re trying to conceive or in your first trimester, one of the most important nutrients that you should consider looking at is folic acid. It’s a B vitamin, and your body uses it to make new cells (like skin and hair). In your baby’s early development, it helps to form the neural tube (which forms the brain and spine) and helps to prevent major birth defects if taken properly. 

    Talbert recommends getting at least 400 micrograms of folic acid every day before you conceive and in the first 12 weeks of pregnancy. You can get this through prenatal vitamins. Folic acid can also be found in foods like green leafy vegetables, beans, and whole grains. However, it can be really difficult to get enough folic acid from food alone, so it’s still a really good idea to add a prenatal vitamin into your routine.


    When you’re pregnant, your body produces around 1250 ml (43.9 fluid ounces) more blood. This is to supply more oxygen to your growing baby and support the placenta. It’s possible that your iron levels may not rise as you produce more blood, and if you don’t get enough, you can become anemic — resulting in you feeling weak and tired. 

    Talbert recommends that you increase your iron intake. This is especially true if you’re a vegetarian or vegan, as red meat is a big source of iron. Most prenatal supplements will already contain all the iron you need. You can also get extra iron from beans, liver, and fortified breakfast cereals. 

    Your health care provider will run blood tests throughout your pregnancy. They’ll let you know if your iron levels are low, but you can always ask for an extra blood test if you think you might be anemic. Shortness of breath, fatigue and pale skin are all signs that you might be experiencing iron deficiency anemia.

    Fatty acid DHA

    You may have already heard that oily fish like mackerel, salmon, and sardines can be great for heart health and lowering blood pressure because they contain omega-3 fats. 

    In the UK, the NHS recommends that you eat no more than two portions of oily fish per week when you’re pregnant. Similarly, the FDA recommends that if you’re pregnant and breastfeeding, you can eat between two and three portions of fish per week, but you should speak to your health care provider about which seafood is better to eat at this time. However, there are other ways to get omega-3 fats.

    DHA or Docosahexaenoic acid is an omega-3 fatty acid that is thought to be important in brain and neuron development in the fetus,” says Dr. Flanagan. “Fatty acids are used in neuron development and ‘insulating’ the nerve pathways.” 

    General guidelines recommend 200 mg DHA daily in pregnancy. Not all prenatal supplements contain this one, though, so you might want to take an extra supplement, says Talbert. Speak to your health care provider about finding an omega-3 supplement that specifically includes DHA, as not all of them do. 

    Vitamin D

    Pregnancy doesn’t deplete your levels of vitamin D as it does with some other nutrients, explains Talbert. However, one of the best sources of vitamin D is sunlight, and if you don’t live in a place that gets lots of sunshine, it can be really difficult to get what you need. 

    Anyone can be deficient in vitamin D. Studies have highlighted that this can be linked with an increased risk of complications during pregnancy, such as gestational diabetes (when you develop diabetes during your pregnancy), preeclampsia (when your blood pressure rises dramatically during pregnancy), and preterm (or early) birth.

    Vitamin D is important for your baby’s development, too, because it can help strengthen their bones and teeth. Speak to your health care provider to find out how much vitamin D you should be taking. If you don’t live in a place with lots of sunlight or work inside for a lot of the day, you may have a deficiency and not know about it. 


    Calcium is another mineral that doesn’t necessarily drop when you’re pregnant, but your levels may already be low. It plays a really important role in supporting your developing baby’s skeleton and nervous and circulatory systems. Milk, cheese, and other dairy products are great sources of calcium. You can also get it from leafy greens and soy products. 

    Your body will only absorb around 500 mg of calcium at a time. So it’s good to either split your supplements up or eat high-calcium foods little and often. Speak to your health care provider about how much calcium you should be getting in your diet. 


    You may have heard of calcium and vitamin D before but not be totally sure what choline is. That’s completely normal, so let us explain. Choline is a nutrient similar to B vitamins and can be found in meat, fish, and multigrain. It’s important during pregnancy as it helps in the development of your baby’s brain and spinal cord. It’s estimated that less than 10% of pregnant women actually consume the correct amount of choline. 

    When should you start taking prenatal vitamins and other supplements?

    As a general rule, as soon as you know you want to have a baby or you might be pregnant, it’s good to start taking “If the pregnancy is planned, it is ideal to start about three cycles (or months) before you are pregnant,” says Dr. Flanagan. This ensures the crucial nutrients are well stocked in the system prior to starting a pregnancy. 

    Of course, this isn’t always the case, and you might not have been trying to get pregnant when you conceived. This is totally fine, and starting to take prenatal vitamins and other supplements as soon as you find out you’re pregnant will also help you, says Flanagan. 

    How important are prenatal vitamins and other supplements?

    Your body changes in so many ways during pregnancy, and it may not feel like the best time to start introducing new things into your diet. If you’re at all confused or worried about the prenatal vitamins that you’ve been advised to take, then lean on your health care provider for support and information. 

    “Generally, prenatal vitamins are well tolerated,” says Talbert. “However, some women do experience nausea and or constipation.” 

    If you’re struggling to take your prenatal supplements, then you can try having them with a meal or right before going to bed to avoid any sickness. If you don’t like taking tablets, you might also want to try gummy supplements. However, Talbert highlights that you should double-check they contain the right amount of nutrients before purchasing them. 

    Dr. Flanagan recommends drinking more water while you take prenatal vitamins and other supplements and, if your medical professional recommends it, try a daily stool softener. This may ease any constipation you have. 

    Even if you never take any prenatal vitamins or other supplements, says Flanagan, “statistically speaking, the pregnancy is likely to be unaffected, and no adverse outcomes would occur.” However, health care providers recommend that you do so as it’s a really easy way to boost nutrients quickly for both you and your growing baby. 

    Prenatal vitamins: The takeaway

    Prenatal supplements can be taken to boost the nutrients you need when you’re trying to conceive and during pregnancy. They shouldn’t be used as a substitute for a healthy diet but may help you feel more energized and give your baby everything they need to develop. 

    It’s important to remember that you should stick to the recommended dosage. “If the prenatal vitamins are taken as directed, no one will take too many,” says Dr. Flanagan. 

    Of course, you want to make sure that you’re talking to your health care provider continuously about what stage in your pregnancy you’re at and what your needs might be, so you can ensure you’re taking the prenatal vitamins that are right for you.


    “About Folic Acid.” NHS, Accessed 22 Aug. 2022.

    Basak, Sanjay, et al. “Maternal Docosahexaenoic Acid Status during Pregnancy and Its Impact on Infant Neurodevelopment.” Nutrients, vol. 12, no. 12, Nov. 2020, Accessed 22 Aug. 2022.

    Goldstein, Rebecca F., et al. “Association of Gestational Weight Gain With Maternal and Infant Outcomes: A Systematic Review and Meta-Analysis.” JAMA: The Journal of the American Medical Association, vol. 317, no. 21, June 2017, pp. 2207–25. Accessed 22 Aug. 2022.

    Greenberg, James A., et al. “Folic Acid Supplementation and Pregnancy: More than Just Neural Tube Defect Prevention.” Reviews in Obstetrics and Gynecology, vol. 4, no. 2, Summer 2011, pp. 52–59. Accessed 22 Aug. 2022.

    Haugen, Margaretha, et al. “Vitamin D Supplementation and Reduced Risk of Preeclampsia in Nulliparous Women.” Epidemiology , vol. 20, no. 5, Sept. 2009, pp. 720–26. Accessed 22 Aug. 2022.

    “How Your Baby Develops Week to Week.” NHS Inform, Accessed 22 Aug. 2022. 

    Hytten, F. “Blood Volume Changes in Normal Pregnancy.” Clinics in Haematology, vol. 14, no. 3, Oct. 1985, pp. 601–12. Accessed 22 Aug. 2022.

    “Iron Deficiency Anaemia.” NHS, Accessed 22 Aug. 2022.

    Korsmo, Hunter W., et al. “Choline: Exploring the Growing Science on Its Benefits for Moms and Babies.” Nutrients, vol. 11, no. 8, Aug. 2019, Accessed 22 Aug. 2022

    Mousa, Aya, et al. “Macronutrient and Micronutrient Intake during Pregnancy: An Overview of Recent Evidence.” Nutrients, vol. 11, no. 2, Feb. 2019, Accessed 22 Aug. 2022.

    “Osteoporosis Prevention With Calcium: Foods, Supplements, Daily Intake.” Cleveland Clinic, Accessed 22 Aug. 2022.

    Pilz, Stefan, et al. “The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data.” International Journal of Environmental Research and Public Health, vol. 15, no. 10, Oct. 2018, Accessed 22 Aug. 2022.

    “Vitamins and Minerals - Calcium.” NHS, Accessed 22 Aug. 2022.

    “Foods to Avoid in Pregnancy.” NHS, Accessed 22 Aug. 2022.

    “Vitamins, Supplements and Nutrition in Pregnancy.” NHS, Accessed 22 Aug. 2022.

    “When Should You Start Taking Prenatal Vitamins?” Cleveland Clinic, 6 Jan. 2022, Accessed 22 Aug. 2022.

    Zhang, Cuilin, et al. “Maternal Plasma 25-Hydroxyvitamin D Concentrations and the Risk for Gestational Diabetes Mellitus.” PloS One, vol. 3, no. 11, Nov. 2008, p. E3753. Accessed 22 Aug. 2022.

    “Advice about eating fish: For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1 – 11 Years.” FDA, Accessed 22 Aug. 2022.

    History of updates

    Current version (19 January 2023)

    Medically reviewed by Dr. Charlsie Celestine, Obstetrician and gynecologist, New Jersey, US

    Published (23 December 2019)

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