Roles of Vitamin B in Pregnancy

Maintaining a healthy & balanced diet at all stages of life is important, but when you’re pregnant you have even more reason to take care of your body to ensure your little one grows into a healthy, bouncing baby!  B vitamins, which you’ll often hear referred to as the vitamin B complex, are particularly important aspects of your nutrition during pregnancy, especially vitamins B6, B9, and B12. These three specifically help minimize the risk of birth defects as well as relieve some symptoms of pregnancy.

This is why taking quality prenatal vitamins is a great way to assure you are getting all the vitamins you and baby need for a healthy pregnancy. Of course, prenatal vitamins are not meant to replace a healthy diet, but to support one.

Crucial Roles of Vitamin B in a Healthy Pregnancy

The entire B complex of eight vitamins plays a crucial role in your strength and health while your baby is developing. During your first and third trimesters, most women feel more tired and run down than usual.

Even though the B complex can come in great supplements, the best way to absorb these nutrients is through vitamin-rich foods!
Vitamin B rich foods help boost your natural energy with these nourishing vitamins for your growing baby. Take a look at the roles and benefits of all the B vitamins and find out how to get enough of each to ensure a happy, healthy pregnancy.

Vitamin B1: Thiamine

Since Thiamine plays a major role in the development of your baby’s brain, aim to consume 1.4 mg every day. Below are natural sources of vitamin B1, so incorporate these foods into your diet to keep your baby’s brain development on track.

Natural Food Sources of Vitamin B1:

  • Peas
  • Oats
  • Pork
  • Lentils
  • Pecans
  • Salmon
  • Brazil Nuts
  • Dried Beans
  • Wheat Germ
  • Nutritional Yeast
  • Whole Grain Pasta
  • Fortified bread or Cereals

Vitamin B2: Riboflavin

Riboflavin is essential for good eye health and it has the added benefit of giving your skin a fresh, healthy glow – cue the compliments from friends and family about how great you look during your pregnancy! This is also true for your baby.
As with all B vitamins, riboflavin is water-soluble and therefore not stored in your body; this means you need to get a good, healthy dosage of around 1.4 mg each day when pregnant compared to the usual 1.1 mg for non-pregnant women.
Whole grains, fortified foods, and dark and leafy greens are rich sources of vitamin B2.

Natural Food Sources of Vitamin B2:

  • Almonds (roasted is an excellent source)
  • Sweet Potatoes
  • Carrots
  • Oats
  • Peas
  • Tempeh
  • Broccoli
  • Spinach
  • Fenugreek
  • Asparagus
  • Mushrooms
  • Whole Grains
  • Nutritional Yeast
  • Fortified Cereals
  • Brussel Sprouts
  • Cheese:  cottage and ricotta
  • Milk
  • Eggs
  • Natural Yogurt
  • Wild Salmon (highest concentration of B2 found in animal sources)
  • Pork, Chicken, Beef (Liver and Kidney offer high amounts)

What Vitamin B2 Aids In Pregnancy

  • promotes good vision, healthy skin, the development and growth of baby’s bones, muscles, and nerves.
  • lowers risk of developing preeclampsia, a pregnancy complication

Signs You Do Not Get Enough Vitamin B2

Riboflavin deficiency signs include anemia, magenta (dry and red tongue), skin rash, dermatitis, dryness and cracking around the mouth, nose, and/or lips. You also have a B2 deficiency risk if you are lactose intolerant or anorexic. Be sure you are eating nutrient-rich foods AND taking a prenatal vitamin.

If you are dealing with an eating disorder while pregnant, please don’t hesitate to speak with your healthcare provider. They can provide you with help, suggestions, and resources!

Contact a Pregnancy Educator at the American Pregnancy Association by calling 1-800-672-2296 M-F 10am-6pm to discuss your concerns, get resources, or to ask questions about your pregnancy.

Vitamin B3: Niacin

Vitamin B-3 has a whole host of benefits for your body; it can improve digestion, reduce nausea and take the edge off debilitating migraines. Aim for around 18 mg every day.

“Intake of more than 35 mg has not been studied in pregnant women” – Merck Manuals Online Medical Library

Therefore it is not recommended for pregnant women to consume doses larger than 18 mg of vitamin B3 when it comes to supplementation.
Sunflower and chia seeds are high in B3, along with organ meats and tuna but too much of the wrong tuna during pregnancy can expose you to high levels of mercury. This is why the American Pregnancy Association stands behind, Safe Catch Elite canned tuna. Below are more natural sources of vitamin B3.

Natural Food Sources of Vitamin B3:

  • Turkey
  • Venison
  • Wild Salmon
  • Chicken Breast
  • Peanuts
  • Crimini Mushrooms
  • Liver
  • Tuna
  • Peas
  • Tahini
  • Kidney Beans
  • Grass-fed Beef
  • Sunflower Seeds
  • Avocados
  • Asparagus
  • Tomatoes
  • Bell Peppers
  • Sweet Potato
  • Brown Rice

How Vitamin B3 Aids In Pregnancy

  • Essential for your baby’s brain development
  • Keeps nervous systems, mucous membranes, and skin healthy
  • Improves digestion, eases nausea and can relieve painful migraines for mom

What You Must Know About Vitamin B3 During Pregnancy

Niacin is one vitamin you do not want to overdose on during pregnancy. If you are on a niacin supplement before your pregnancy, you need to speak to your doctor about stopping the supplementation while you are pregnant and taking regular prenatal vitamins.

Vitamin B5: Pantothenic Acid

Pregnancy can do some strange and frustrating things to our bodies, one of which is painful leg cramps. Luckily, vitamin B5 can help to ease these cramps, so aim to consume 6 mg every day. It also has the added benefit of producing important pregnancy hormones.

Whole grains and fortified cereals are a fabulous source for B5 so that’s breakfast covered, but you’ll also find the vitamin in egg yolks, brown rice, cashew nuts, and broccoli, all of which are perfect ingredients for a delicious and nutritious stir fry! Below are several other sources of B5.

Natural Food Sources of Vitamin B5:

  • Sunflower Seeds
  • Sweet Potato
  • Avocado
  • Whole Grains or Fortified Cereals
  • Crimini Mushrooms
  • Oats
  • Organic Corn
  • Cauliflower
  • Wild Salmon
  • Chicken Breast
  • Milk
  • Oranges
  • Bananas
  • Sun-dried Tomatoes
  • Trail Mix (Seeds, Nuts and Chocolate Chips)

What Vitamin B5 Aids In Pregnancy

  • Helps metabolize fats, proteins, and carbohydrates
  • Helps to prevent pregnancy-related muscle cramps
  • Aids in the release of stress-relieving hormones

Vitamin B6: Pyridoxine

Pyridoxine is vital for the development of your baby’s nervous system and brain throughout each week of your pregnancy, but it has some beneficial side effects for you, too.

Part of its role in the body is to produce norepinephrine and serotonin, two essential neurotransmitters which aid a whole host of metabolic functions. Vitamin B6 during pregnancy can also help to alleviate nausea and vomiting which are perhaps two of the very worst early side effects of pregnancy.

To maximize both you and your baby’s health, you should consume between 25 and 50 mg each day.  The University of Michigan recommends managing nausea by taking 10 to 25 mg of Vitamin B6 3 times a day.  The National Library of Medicine research reports that excessive vitamin B6 does not show to be associated with any birth defects or malformations for the developing baby.

However, despite it being a very safe vitamin to consume, doctors recommend not to exceed the daily dose of 100 mg (in supplements alone); in this case, more isn’t better.

You can find B6 in beans, bananas, papayas, whole grain cereals, and several other natural food sources great for pregnancy smoothies rich in B6.

Natural Food Sources of Vitamin B6:

  • Garlic
  • Beans
  • Sweet Potatoes
  • Chickpeas
  • Avocados
  • Hazelnuts
  • Sunflower Seeds
  • Brown Rice
  • Prune Juice
  • Spinach
  • Bananas
  • Papayas
  • Chicken
  • Pork Loin
  • Wild Salmon
  • Turkey
  • Grass-fed Beef
  • Safe-Catch Elite Tuna

How Vitamin B6 Aids In Pregnancy

  • Helps to prevent low birth weight
  • Essential to the development of your baby’s brain and nervous system
  • Helps maintain blood glucose at healthy levels
  • May help with morning sickness

What You Must Know About Vitamin B6 During Pregnancy

Vitamin B6 in excess amounts can lead to numbness and nerve damage for individuals. Be sure you know the amount supplied in your prenatal vitamin and the amount in your diet does not exceed 100 mg per day.

Vitamin B7: Biotin

Pregnancy often causes a deficiency in vitamin B7, so make sure you’re eating plenty of biotin-rich foods such as oats, milk, mushrooms, and Swiss Chard. The US Food and Nutrition Board of the National Academy of Science’s Institute of Medicine recommends at least 30 mcg of vitamin B7 for pregnant women.
If you’re planning on breastfeeding, note that the recommended intake for nursing moms is 35 mcg, so you may need to slightly increase your intake when your little bundle of joy arrives.

Natural Food Sources of Vitamin B7:

  • Oats
  • Avocado
  • Spinach
  • Broccoli
  • Cauliflower
  • Legumes
  • Royal Jelly
  • Fortified Cereal
  • Brewer’s Yeast
  • Blackstrap Molasses
  • Swiss Chard
  • Wild Salmon
  • Mushrooms
  • Wheat Bran
  • Cheese
  • Raspberries
  • Cauliflower
  • Egg Yolk
  • Chicken
  • Potatoes
  • Soy
  • Milk
  • Nuts
  • Liver
  • Pork

What Vitamin B7 Aids in Pregnancy

  • Helps hair loss, brittle nails, and skin rashes
  • Essential to embryonic growth during your pregnancy

Signs You Do Not Get Enough Vitamin B7

Vitamin B7 deficiencies can cause many symptoms like listlessness, depression, hair thinning, tingling sensations in legs and arms or hallucinations.

What You Must Know About Vitamin B7 During Pregnancy

Too large doses of biotin over long periods of time could lead to rare side effects like allergies, acne or miscarriages during pregnancy. These side effects are rare but always consult with your OBGYN when it comes to prenatal vitamins and your diet.

Vitamin B9: Folic Acid

It’s fairly common knowledge that folic acid is one of the most important B vitamins to take during pregnancy and for a very good reason. The proper amount of folic acid reduces the risk of your baby developing neural tube birth defects like spina bifida. It’s also responsible for helping to produce red blood cells which are obviously important for both you and your growing baby.

You should be consuming 400 – 800 mcg (micrograms) of vitamin B9 every day throughout your entire pregnancy, which translates to 0.4 – 0.8 mg (milligrams). If you’re trying to conceive it’s also recommended that you consume this same amount of folic acid (400 mcg pre-pregnancy is generally fine) to maximize your chances of getting pregnant.

On top of this, try to increase your consumption of foods which naturally contain the vitamin.

Folic Acid Dosages Breakdown

  • 400 mcg (0.4 mg) a day if you are trying to conceive
  • 400 – 800 mcg (0.4 – 0.8 mg) a day during pregnancy
    • Not to exceed 1000 mcg (1.0 mg) per day during pregnancy

Lentils, citrus fruits, particularly oranges and grapefruits, are high in folic acid, as are dark green veggies like spinach, broccoli, and asparagus.

Natural Food Sources of Vitamin B9:

  • Lentils
  • Spinach
  • Great Northern Beans
  • Fortified Cereals
  • Asparagus
  • Avocado
  • Peas
  • Nuts
  • Dried Beans
  • Egg Noodles
  • Beef Liver
  • Sprouts

What Vitamin B9 Aids In Pregnancy

  • Prevents NTDs (neural tube defects) like anencephaly (a brain defect) or spina bifida (spinal cord defect). NTDs can develop at the earliest stage of pregnancy, so it is important to be consuming folic acid from the time you start trying to conceive.
  • Reduces the risk of birth defects like cleft lip, cleft palate, some heart defects
  • Reduces the risk of preeclampsia during pregnancy
  • Important for the growth of the placenta, synthesis of DNA and the development of the baby
  • Essential for red blood cell production and helps prevent forms of anemia

The majority of prenatal vitamins supply 800 – 1,000 mg of vitamin B9. Be sure to not consume any more than 1,000 mg a day, unless you are advised by your doctor.

When Do You Need Extra Vitamin B9?

  • Those pregnant with twins, your doctor could have your take 1,000 mg daily
  • Overweight women may need more than 400mg a day, ask your doctor before you become pregnant and before you take extra
  • Those taking anti-seizure or diabetes meds may be told to take more daily
  • If your developing baby has already developed an NTD, your doctor may have you take 4,000 mg daily
  • If you have Methylenetetrahydrofolate reductase, a genetic mutation that makes it harder to produce folic acid (folate) in your body

It is important you understand all the prenatal vitamin limits when choosing your prenatal vitamins.

Vitamin B12: Cobalamin

Vitamin B12 is important for maintaining the health of your nervous system, but it’s also believed that when combined with folic acid during pregnancy, B12 supplements can help to prevent spina bifida and other spinal and central nervous system birth defects in your baby, too.
You can find B12 in fortified foods (soy or soy milk), fish, poultry, eggs, and milk and should aim for around 2.6 mcg (micrograms) per day, but using supplements to achieve this intake will help.

Natural Food Sources of Vitamin B12:

  • Wild Salmon
  • Soy Milk or Soy Products (fortified with B12 on the label)
  • Shrimp
  • Grass-fed Beef Liver or Tenderloin
  • Yogurt
  • Fortified Cereals
  • Red Meat
  • Swiss Cheese
  • Milk
  • Cottage Cheese
  • Cod

How Vitamin B12 Aids In Pregnancy

  • Essential for baby’s neural tube formation, brain and spine development
  • Together with Folate (B9), it works to produce DNA synthesis and red blood cells
  • Aids the development and functioning of your brain, nerves and blood cells
  • Helps improve your energy, mood and stress levels by aiding the metabolization of fats, carbohydrates, and proteins.
  • Helps maintain the normal central nervous system and neurological functions by regulating the synthesis of myelin and fatty acids.

Signs You Do Not Get Enough Vitamin B12

For women of childbearing age, B12 deficiencies are quite rare, but if they occur it increases the risk of your baby developing an NTD (Neural Tube Defect). This is similar to problems that may result from low B9 (folate).

These serious birth defects can include:

  • Anencephaly – the spinal cord and brain do not form properly
  • Encephalocele – parts of the brain begins to push out
  • Spina bifida – the baby’s spine does not form correctly

If any of these birth defects run in the family a triple screen test will be necessary.
If you believe you may have a vitamin B12 deficiency and are suffering from depression, anxiety, fatigue or insomnia, contact your doctor immediately.
Brain damage can occur in severe deficiency conditions, it is very important you share all your concerns with your doctor to prevent any vitamin deficiencies from causing damage to your body or your developing baby’s body.

Do You Need a B12 Supplement?

Your doctor may ask you to supplement B12 with folic acid if you are vitamin B12 deficient before pregnancy. Both of these supplements together will help prevent birth defects in developing babies as well as helps combat defects that affect the spine and central nervous system. Prenatal vitamins should help with most deficiencies, ask your doctor if you have any questions.
It is important to note that while the Institute of Medicine (IOM) does not set an upper limit because of B12’s “low potential for toxicity,” you should still speak with your doctor before adding in an additional B12 supplement (on top of a prenatal vitamin) if you are not deficient.

Vitamin B Roles For Pregnancy Cheat Sheet

Here’s a handy cheat sheet to help you remember exactly how each B vitamin can support you and your growing baby throughout pregnancy.

  • B-1 (Thiamine): 1.4 mg – Supports baby’s healthy brain development
  • B-2 (Riboflavin): 1.4 mg – Keeps eyes healthy and skin glowing
  • B-3 (Niacin): 18 mg – Eases morning sickness, keeps nausea at bay and improves digestion
  • B-5 (Pantothenic Acid): 6 mg – Reduces leg cramps and helps produce essential pregnancy hormones
  • B-6 (Pyridoxine): 25 – 50 mg – Aids the development of baby’s nervous system and brain (don’t exceed 100 mg)
  • B-7 (Biotin): 30 mcg – Deficiency is often caused by pregnancy, so increased consumption is vital
  • B-9 (Folic Acid): 400 – 800 mcg – Plays a huge role in reducing the risk of birth defects (don’t exceed 1000 mcg)
  • B-12 (Cobalamin): 2.6 mcg – Maintains and supports the development of you and your baby’s nervous system

B Vitamin Complex Supplements During Pregnancy

Typically, prenatal vitamins contain the perfect blend of B vitamin complex to fulfill all the recommended dosages we’ve outlined here. There’s no need to routinely supplement any B vitamins other than taking your prenatal vitamin; simply enjoy a well-balanced diet alongside it and look forward to the arrival of your little one!
If you have any questions be sure to ask your OBGYN. You and your developing baby’s health depend on you asking questions, staying healthy and stress-free. Enjoy being pregnant, and eat healthy for two (your baby needs only about 300 extra healthy calories per day unless otherwise advised by your doctor).

Want to Know More?


Compiled using information from the following sources:

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3. Pitkin RM. Folate and neural tube defects. Am J Clin Nutr. 2007; 85:285S–288S.

4. Harvard’s Nutrition Source on Vitamin B.

5. Food sources of riboflavin.

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7. Shrim, A., Boskovik, R., Maltepe, C., et al. Pregnancy outcome following use of large doses of vitamin B6 in the first trimester. Journal of Obstetrics & Gynaecology, 26(8), 749-51.

8. Paediatr Perinat Epidemiol. 2012 Jul;26 Suppl 1:55-74. doi: 10.1111/j.1365-3016.2012.01277.x. Interventions with vitamins B6, B12 and C in pregnancy.

9. U.S. Department of Health and Human Services. NIH. National Institutes of Health. Office of Dietary Supplements: Vitamin B

10. The Motherisk Program, Division of Clinical Pharmacology/Toxicology, Hospital for Sick Children, University of Toronto, Ontario, Canada. “Pregnancy outcome following use of large doses of vitamin B6 in the first trimester”

11. National Institutes of Health (NIH): Vitamin B12 – Fact Sheet for Health Professionals.

12. National Library of Medicine, Pregnancy outcome following use of large doses of vitamin B6 in the first trimester
13. University of Michigan, Vitamin B6 for Morning Sickness