Vitamin B Complex During Pregnancy: Why They Are Important

Vitamin B Complex During Pregnancy

B vitamins support our body in converting food (carbohydrates) into energy (glucose). It is important for the expectant mother to include all the B vitamins, known as B complex vitamins, in her diet, as they are water-soluble and are not stored by the body. These vitamins help the mother to get adequate nutrition and support the baby’s growth and development. MomJunction tells you the importance and requirement of all these eight B vitamins.

1. Vitamin B1 (Thiamine)

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Vitamin B1, also known as Thiamin or Thiamine, performs many important functions during your pregnancy.

  • It enables both you and your baby to convert carbohydrates into energy.
  • Plays a major role in baby’s brain development.
  • Helps your muscles, nervous system and heart function normally.

[Read: Benefits Of Vitamin C During Pregnancy]

How much do you need?

The recommended daily allowance (RDA) of vitamin B1 during pregnancy is 1.4 milligrams (mg) irrespective of a woman’s age (1). Women carrying more than one baby should increase their thiamine intake.

Sources of vitamin B1

Thiamine is found in several foods. Whole grain products, cereals, fortified bread, pasta, peas, dried beans, some fish, and pork are good sources. Dairy products, fruits, and vegetables also contain vitamin B1, but in small amounts (2).

Take a look at the amount of vitamin B1 present in each of these foods:

  • 3/4th cup whole grain cereal – 1.5mg
  • 1 cup white rice (cooked) – 1.2mg
  • 1 cup brown rice (cooked) – 0.2mg
  • 1/2 cup oats – 0.6mg
  • 1/4 cup pecans – 0.4mg
  • 1/4 Brazil nuts – 0.4mg
  • 1/2 cup peas (cooked) – 0.2mg
  • 1/2 cup lentils (cooked) – 0.2mg
  • 1/4 cup wheat germ – 0.5mg
  • 1/2 cup split peas (cooked) – 0.2mg
  • 1 cup spinach noodles (enriched) – 0.4mg
  • 3 ounces rainbow trout – 0.3mg
  • 3 ounces salmon – 0.3mg
  • 3 ounces ham steak (cured boneless) – 0.3mg
  • 3 ounces Florida pompano – 0.7mg
  • 3 ounces pork tenderloin – 0.8mg

What happens if you do not have enough vitamin B1?

Early signs of vitamin B1 deficiency are nausea, fatigue, nerve damage and headache.

Severe deficiency leads to beriberi – wet, dry or cerebral depending on the body part it affects. Wet beriberi is an acute form which causes poor blood circulation and edema, leading to heart failure. The dry form of the disease causes gradual nerve degeneration in the arms and legs, loss of reflexes and muscle atrophy.

[Read: Vitamin E During Pregnancy]

Thiamine deficiency is common in developing countries, where people eat processed rice. Thiamine present in the outer coating of rice is removed while processing.

In industrial countries, alcohol is the main reason for vitamin B1 deficiency as it adversely affects thiamine absorption in the body.

In developed countries like the US, foods are usually fortified with vitamin B1, and also multivitamins and prenatal vitamins contain it. Therefore, the deficiencies are rare.

Do you require a supplement?

According to the US Department of Health, you can get the necessary vitamin B1 from foods like whole grain and fortified cereals, and a balanced diet. In case you don’t, you may take a prenatal supplement or multivitamin to get your RDA.

What happens if you take too much?

There is no evidence to show the adverse effects of excess thiamine intake while you are pregnant.

2. Vitamin B2 (Riboflavin)

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Vitamin B2, also known as Riboflavin, is a co-enzyme that involves in many reactions in the body.

  • It plays a prominent role in promoting healthy skin, good vision, growth and development of baby’s muscle, bone, and nerve.
  • It lowers the risk of getting preeclampsia.

[Read: Benefits Of Prenatal Vitamins]

How much do you need?

The recommended daily allowance (RDA) of vitamin B2 during pregnancy is 1.4mg. (3).

Sources of vitamin B2

Milk, fortified cereals, wheat flour and bread products are all excellent sources of vitamin B2.

Take a look at the amount of riboflavin present in each of the following foods:

  • 1 cup non-fat milk – 0.5mg
  • 1 cup low-fat yogurt (plain) – 0.5mg
  • 1 1/2 ounces Cheddar cheese – 0.2mg
  • 1/2 cup partly skimmed Ricotta cheese – 0.2mg
  • 1/2 cup Cottage cheese (1%) – 0.2mg
  • 1/2 cup mushrooms – 0.2mg
  • 1/2 cup soybeans – 0.3mg
  • 3 ounces pork spare rib (tender) – 0.3mg
  • 1/2 cup spinach (cooked) – 0.2mg
  • 3 ounces tempeh (cooked) – 0.3mg
  • 1 hard-boiled egg (large) – 0.3mg
  • 3 ounces skinless duck – 0.4mg
  • 1/4 cup almonds – 0.3mg

Caution: UV light can destroy riboflavin in foods, so these foods should be kept in opaque containers away from light.

What happens if you do not have enough vitamin B2?

The signs of riboflavin deficiency are skin rash, anemia, dermatitis, magenta (red and dry) tongue, cracking and dryness around lips, mouth and nose.

You are at a higher risk of deficiency if you are suffering from anorexia (eating disorder) and lactose-intolerance (since you will be avoiding dairy products).

[Read: Vitamin K During Pregnancy]

Do you require a supplement?

The US Department of Health says that you can obtain the necessary riboflavin through a healthy diet containing multi-grains, eggs, meat, dairy products, fortified cereals and green vegetables. If you use supplements, do not take them beyond the daily recommended limit.

What happens if you take too much?

There is no evidence about the adverse effects of excess intake of vitamin B2. Any vitamin B2 that is not used by the body is usually excreted through urine.

3. Vitamin B3 (Niacin)

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Vitamin B3, also called niacin, is present in two forms – nicotinamide and nicotinic acid, both of which help in releasing energy from food.

  • It keeps skin, nervous system and mucous membrane healthy.
  • It is essential for the baby’s brain development.
  • It helps ease nausea, subside a painful migraine and improves digestion.

Niacin is classified into pregnancy category C by the US FDA. Studies have revealed that it can cause harm in animals, but further research is required to know its effect on humans.

[Read: Why Do Pregnant Women Need Magnesium?]

How much do you need?

The recommended amount of vitamin B3 during pregnancy is 18mg per day (4). You can include up to 35mg per day, and vitamin B3 intake between these two levels is acceptable while you are pregnant. . According to the Merck Manuals Online Medical Library, ‘intake of more than 35mg has not been studied in pregnant women’, therefore it is not recommended.

Sources of vitamin B3

Both nicotinamide and nicotinic acid are found in food. You can include the following foods to get the required amount of niacin:

  • 4 oz chicken breast (roasted) – 14.41mg
  • 4 oz salmon (broiled or baked) – 11.34mg
  • 4 oz yellowfin or tuna (broiled or baked) – 13.54mg
  • 4 oz Turkey – 8.50mg
  • 4 oz calf’s liver (lightly fried) – 9.61mg
  • 4 oz Venison – 7.61mg
  • 4 oz Halibut (broiled or baked) – 8.08mg
  • 5 oz Crimini mushrooms (raw) – 5.39mg
  • 4 oz lamb loin (roasted) – 7.75mg

What happens if you do not have enough vitamin B3?

Vitamin B3 deficiency is rare as you will easily get the daily requirement by the available food sources or from tryptophan (an amino acid, which converts to niacin in the body) present in dietary proteins (5). The deficiency is usually higher in those who consume corn or sorghum as their staple diet. Niacin is present in bound form in these sources.

Do you require a supplement?

Supplementation is usually not needed since you will get enough vitamin B3 in an average diet.

What happens if you take too much?

There are no adequate studies to determine the effects of vitamin B3 taken in high doses during pregnancy. They are otherwise known to cause skin flushes and liver damage.

Oral niacin is classified under Pregnant C category by the US Food and Drug Administration (FDA) as the drug has not been studied completely in pregnant women. As there is no proper evidence to determine its effects on the mother and fetus, the drug should be taken only if the doctor prescribes it.

[Read: Vitamin D During Pregnancy]

The use of FDA approved niacin at therapeutic doses taken under the doctor’s supervision, lowers triglycerides and cholesterol. But the dosage is 6g, which is far higher than the recommended intake during pregnancy. Therefore, you should stop taking niacin during pregnancy especially when you are taking it for low HDL or high LDL cholesterol. But, if you are taking for high triglycerides, you should bring it your doctor’s notice as triglycerides increase during pregnancy.

4. Vitamin B5 (Pantothenic Acid)

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Vitamin B5 or Pantothenic Acid is a component of coA (coenzyme A), essential for various chemical reactions in the cells.

  • It helps prevent muscle cramps during pregnancy.
  • It releases hormones which help you fight stress.
  • It is helpful for metabolism of proteins, carbohydrates and fats.

How much do you need?

Your body requires 6mg of pantothenic acid every day during pregnancy (6).

Sources of vitamin B5

Pantothenic acid is found in almost all varieties of meat and vegetables. Here are some good options to get the necessary amount of this vitamin:

  • 1/4 cup sunflower seeds (dry and roasted) – 2.3mg
  • 3/4 cup whole grain cereals (fortified) – 10mg
  • 8 ounces low-fat yogurt (plain) – 1.3mg
  • 5 ounces Crimini mushrooms (raw) – 2.1mg
  • 1 baked sweet potato (medium sized) – 1mg
  • 1/2 avocado (medium sized) – 1.1mg
  • 1/2 cup yellow corn (cooked) – 0.7mg
  • 1 cup non-fat milk – 1mg
  • 1 potato (baked) – 0.7mg
  • 1/2 cup assorted chocolate chips, seeds and salted nuts – 0.7mg
  • 1 cup oatmeal (cooked) – 0.5mg
  • 1/2 cup mushrooms (raw) – 0.5mg
  • 1 orange (medium) – 0.5mg
  • 1 banana (medium) – 0.5mg
  • 1/2 cup cauliflower (boiled) – 0.3mg
  • 1/2 cup broccoli (boiled) – 0.3mg
  • 1 hard-boiled egg (large) – 0.7mg
  • 3 ounces chicken breast (roasted) – 1mg
  • 3 ounces salmon (baked) – 1.2mg

What happens if you do not have enough vitamin B5?

Vitamin B5 deficiency is rare when you are pregnant. There is a risk of its deficiency in women who are severely malnourished or on a diet or suffering from toxemia (an abnormal condition in pregnancy) (7). Symptoms include weakness and chronic fatigue.

Do you require a supplement?

Pantothenic acid is present in almost all foods, and therefore you do not need any additional intake. It is also present in most of the prenatal vitamin supplements.

What happens if you take too much?

Since pantothenic acid is a water-soluble vitamin, the body gets rid of the excess amount through urine. The effects are not known if it is taken in larger amounts than the recommended intake. However, avoid over-consumption.

5. Vitamin B6 (Pyridoxine)

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Vitamin B6, also known as Pyridoxine, is essential for your body to metabolize carbohydrates, proteins and fats. It helps to form red blood cells, neurotransmitters and antibodies.

  • It is essential for the development of your baby’s brain and nervous system.
  • It helps relieve morning sickness and maintains healthy blood glucose levels.
  • It prevents low birth weight in babies (8).

How much do you need?

According to the US Institute of Medicine, the daily requirement of vitamin B6 during pregnancy is 1.9mg (9). However, the tolerable upper intake is 100mg for women around and above 19 years and 80mg for those around and below 18 years.

Sources of vitamin B6

Pyridoxine is found in a variety of foods. Lean meat, fish, beans, and nuts are excellent sources of this vitamin. Fortified cereals and breads are also good sources. Some good options are:

  • 1/2 cup chickpeas (canned) – 0.57mg
  • 1 baked potato (medium with skin) – 0.74mg
  • 1 cup spinach (cooked) – 0.44mg
  • 8oz prune juice – 0.56mg
  • 1 banana (medium) – 0.43mg
  • 1/2 avocado – 0.26mg
  • 1 cup brown rice (long grain, cooked) – 0.28mg
  • 1oz hazelnuts (dry and roasted) – 0.18mg
  • 1oz sunflower seeds (dry and roasted) – 0.23mg
  • 3oz chicken (roasted) – 0.46mg
  • 3oz lean pork loin (broiled) – 0.49mg
  • 3oz farmed salmon (cooked) – 0.55mg

What happens if you do not have enough vitamin B6?

Mild deficiencies are common while severe deficiencies are rare. Early signs of pyridoxine deficiency include depression, sores or mouth ulcers and inflammation of the tongue.

Vitamin B6 deficiency can cause a form of anemia, which is similar to iron deficiency anemia. It also decreases the antibody production and affects immune response.

Do you require a supplement?

According to the US Department of Health, you can get the required amount of this vitamin from a balanced diet. Most prenatal vitamin and mineral supplements contain nearly 100% of RDA.

Caution: If you have morning sickness, you should check with your doctor before taking any pyridoxine supplements as too much is not safe for you as well as your growing fetus.

What happens if you take too much?

A few high potency multivitamins, which you take during pregnancy, contain pyridoxine in excess amounts. You also get a high quantity of this vitamin if you include fortified foods in your diet. Excess intake of vitamin B6 can lead to nerve damage and numbness.

6. Vitamin B7 (Biotin)

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Vitamin B7 or Biotin or H vitamin generates energy from the food you eat. It is, therefore, necessary to form enzymes that break down carbohydrates, proteins and fats.

  • It is essential for embryonic growth during pregnancy.
  • It is helpful to treat skin rash, brittle nails and hair loss.

How much do you need?

As per the US Food and Nutrition Board of the National Academy of Science’s Institute of Medicine, the recommended daily allowance of vitamin B7 during pregnancy is 30mg (10).

[Read: Biotin During Pregnancy]

Sources of vitamin B7

The bacteria residing in your digestive tract is responsible for producing some of your essential biotins. Food sources rich in biotin include egg yolk, liver, milk, oats, swiss chard, mushroom, salmon, pork, cheese, raspberries, cauliflower and molasses.

What happens if you do not have enough vitamin B7?

Research states that biotin is rapidly broken down during pregnancy and therefore its nutritional level declines (11). It is known to cause birth defects in many of the animal species. Almost one-third of pregnant women develop marginal biotin deficiency and it indirectly proves that it can cause congenital anomalies in fetus (12). To rule out the risk of abnormal embryo or fetus, you should make sure you take enough biotin during pregnancy.

Symptoms of vitamin B7 deficiency include thinning of hair, depression, listlessness, hallucinations and tingling sensation in the arms and legs.

Do you require a supplement?

Pregnant women are advised to take prenatal vitamins or multivitamins that include supplemental biotin to help prevent congenital anomalies.

What happens if you take too much?

Taking excess doses of biotin for a long period may lead to certain side effects while you are pregnant. They usually include allergies, miscarriage and acne. However, they are rare. So, consult your doctor for the right dosage.

Also, when you notice an allergy or acne symptoms, you should start cutting down the dosage to less than 250mg per day.

7. Vitamin B9 (Folic Acid)

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Vitamin B9 or Folic Acid is the most important B vitamin to include during pregnancy.

  • It prevents neural tube defects (NTDs), serious birth complications of the brain (like anencephaly) and spinal cord (like spina bifida). The neural tube is a section of the embryo from where your baby’s brain and spine develop.
  • NTDs develop at a very early stage even before you do not know about your conception. Therefore, it is important to take folic acid supplements from the time you try to conceive.
  • According to the US Centers For Disease Control and Prevention (CDC), women should take recommended amount of folic acid from one month before conception and during the first trimester to reduce the risk of NTDs in their babies by 70% (13).
  • It also reduces the risk of other defects like cleft palate, cleft lip and some heart defects in babies and preeclampsia in pregnant women.
  • It is essential for the production of red blood cells to prevent a form of anemia.
  • It is important for the synthesis of DNA, growth of placenta and development of your baby.

How much do you need?

The recommended daily intake of vitamin B9 is 400mcg during pregnancy (14). If you are on prenatal or multivitamins, check whether you are getting the required amount. According to WebMD, here is the quantity of folic acid you can include during pregnancy:

  • When trying to conceive – 400mcg a day
  • First trimester – 400mcg a day
  • Four to nine months of pregnancy – 600mcg a day

According to the US National Institutes of Health, it is advisable to include at least 600mcg a day during pregnancy (15).

Most prenatal vitamins contain 800-1,000mcg folic acid. You should not include more than 1,000mcg a day unless your doctor says so.

When do you need extra vitamin B9?

  • If you are overweight, you should check with your doctor before you try to become pregnant. You may be advised to include more than 400mcg a day.
  • If you are pregnant with a baby who has NTD, your doctor may recommend you to include 4,000mcg a day.
  • If you are having twins, you may be advised to include about 1,000mcg a day.

You may also require extra folic acid in the following cases:

  • A genetic mutation called Methylenetetrahydrofolate reductase makes it difficult to produce folate and folic acid in the body.
  • If you are taking diabetes or antiseizure medications.

There will be almost 3-5% chance of having a pregnancy with NTD, so you should always talk to your doctor before you try to conceive.

Sources of vitamin B9

Folic acid is rich in lentils, dark green vegetables, sprouts, citrus fruits, asparagus, avocado, dried beans, peas and nuts. Some common food options you may include:

  • 3/4th cup fortified cereals – 400mcg
  • 3 ounces beef liver (cooked and braised) – 215mcg
  • 1/2 cup lentils (cooked) – 179mcg
  • 1/2 cup egg noodles (enriched, cooked) – 110mcg
  • 1/2 cup spinach (cooked) – 115mcg
  • 1/2 cup Great Northern beans (boiled) – 90mcg

What happens if you do not have enough vitamin B9?

If you are deficient in folic acid, you will experience anemia, diarrhea, weight loos, appetite loss, sore tongue, weakness, heart palpitations, irritability and headaches.

If the deficiency is mild, you will not notice any symptoms, but may not get enough amounts to support your baby’s early embryonic development.

Do you require a supplement?

Yes, many groups including March of Dimes, American College of Obstetricians and Gynecologists (ACOG) and the US Preventive Services Task Force recommend that all women capable or planning a pregnancy should take a supplement everyday containing 400mcg to 800mcg (0.4 to 0.8mg) of folic acid (16).

What happens if you take too much?

It is unusual to get an overdose of folic acid. You should not take excess than the daily limit unless your doctor recommends doing so.

Consuming excess folic acid can hide the signs of vitamin B12 deficiency, leading to nerve damage (vitamin B12 works closely with vitamin B9). But, it is quite rare among women who are capable of getting pregnant.

Also, studies published in the Journal of Endocrinology explore that an overdose of folic acid in your pregnancy can put your daughters at higher risk of diabetes and obesity later in their life (17).

9. Vitamin B12 (Cobalamin)

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Vitamin B12, also called Cobalamin, has several important functions just like folic acid.

  • It is essential for the synthesis of fatty acids and myelin, which help in maintaining the normal neurological function and central nervous system (CNS).
  • It aids in functioning and development of your blood cells, brain, and nerves.
  • It assists in metabolizing carbohydrates, proteins, and fats and thus improves your mood, energy levels and stress levels when you are carrying.
  • Along with folate, it works to produce red blood cells and DNA synthesis.
  • It also plays a major role in fetus brain development and neural tube formation.

How much do you need?

The recommended daily intake of vitamin B12 is 2.6mcg during pregnancy (18). Taking vitamin B12 along with folic acid is effective.

Sources of vitamin B12

Cobalamin is present in milk, eggs, meat, fish, poultry and shellfish. Some of the best food options include:

  • 4oz snapper (baked or broiled) – 41.39mcg
  • 3.25 oz sardines – 8.22mcg
  • 4oz salmon (baked or broiled) – 3.25mcg
  • 4oz scallops (baked or broiled) – 2mcg
  • 4oz shrimp (streamed or boiled) – 1.69mcg
  • 4oz Halibut – 1.55mcg
  • 4oz Venison – 3.6mcg
  • 4oz calf’s liver (braised) – 41.39mcg
  • 4oz lamb loin (roasted) – 2.45mcg
  • 4oz lean beef tenderloin (broiled) – 2.92mcg

Vegans can include fortified B12 foods like soy milk and soy products to meet their daily requirements. Certain findings from the US study by Tucker, Rich et al 2000, conclude that vitamin B12 fortified foods are better absorbed than naturally found vitamin B12 in foods. Fortified foods use cyanocobalamin or crystalline B12 that are absorbed better.

What happens if you do not have enough vitamin B12?

Vitamin B12 deficiencies are very rare among women of childbearing age. But, if they do occur, they increase the risk of your baby developing NTDs. Some of the serious birth defects include:

  • Spina bifida: Your baby’s spine fails to form correctly.
  • Anencephaly: Brain and spinal cord are not formed properly.
  • Encephalocele: Some part of the brain pushes out into the skull through a hole.

If you have vitamin B12 deficiency, you may suffer from insomnia, fatigue, depression, and anxiety. In a severe deficiency condition, you may have brain damage.

Do you require a supplement?

You may need to take a supplement if you are already deficient in vitamin B12 during pregnancy. But if you are already on prenatal vitamins, an additional supplement is not required.

Doctors also suggest you take vitamin B12 supplement along with folic acid. This will not only prevent birth defects in babies but also combats the defects which affect CNS and spine.

What happens if you take too much?

There are no adverse effects reported so far with excess intake of vitamin B12, according to the Institute of Medicine (19).

A study by the Johns Hopkins Bloomberg School of Public Health has found that women who take excess folate and vitamin B12 may put their babies at high risk of developing autism spectrum disorder, a neurodevelopment condition identified by abnormal communication, social interaction problems and unusual or repetitive behavior (20).

You should discuss with your doctor before you plan to take any vitamin supplements in your pregnancy, even if you have been taking them before this period.

Your nutritional requirements during pregnancy reflect your growing baby’s needs. Only your doctor can tell you about the vitamins, supplements, and diet that you may have to take.

Did you include all or any of these B vitamin sources and supplements while you were pregnant? Share your thoughts in our comment section below.

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Jyoti Benjamin

Jyoti Benjamin has 25 years of experience as a clinical dietitian and currently works in Seattle. She focuses on teaching people the value of good nutrition and helping them lead healthy lives by natural means. Benjamin has a masters in Foods and Nutrition, and has been a longtime member and Fellow of AND (Academy of Nutrition and Dietetics) and the... more

Rebecca Malachi

Rebecca is a pregnancy writer and editor with a passion for delivering research-based and engaging content in areas of fertility, pregnancy, birth, and post-pregnancy. She has been into health and wellness writing since 2010. She received her graduate degree in Biotechnology and Genetics from Loyola Academy, Osmania University and obtained a certification in ‘Nutrition and Lifestyle in Pregnancy’ from Ludwig... more