What prenatal vitamins do you need and when should you start?

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 professional 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. 

Key takeaways 

• Prenatal vitamins can boost the nutrients you need during pregnancy and when you’re trying to conceive.
• Folic acid, iron, vitamin D, calcium, omega-3s, and choline are important nutrients for you and your growing baby.
• Folic acid supplements are among the most important: experts recommend taking at least 400 mcg daily.
• Starting supplements while trying to conceive is ideal, but starting once you're pregnant can still help.
• Supplements are helpful but should not be used as a substitute for a healthy diet.

What are prenatal vitamins and other supplements?

Prenatal supplements can give you a boost of nutrients quickly and easily, so you don’t lose out (sometimes referred to as nutrient deficiencies). 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. Supplements can help you top them up again.

While your health care professional 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. 

What are the best prenatal vitamins and other supplements?

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

• Iron
• Folate
• Calcium
• Vitamin D
• Omega-3 (DHA)

Unless your health care professional 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. 

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

How much folic acid should you take?

Lauren Talbert, RD recommends getting at least 400 mcg 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 trying to conceive or in your first trimester, folic acid is one of the most important nutrients that you should consider looking at. 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 congenital conditions if taken properly. 

Do you need an iron supplement during pregnancy?

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

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. 

Your health care professional 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.

Why do you need DHA (omega-3) in pregnancy?

"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, OB-GYN. “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 Lauren Talbert, RD. Speak to your health care professional about finding an omega-3 supplement that specifically includes DHA, as not all of them do. 

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 professional about which seafood is better to eat at this time. 

Why do you need vitamin D in pregnancy?

Vitamin D is important for your baby’s development because it can help strengthen their bones and teeth. 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.

Pregnancy doesn’t deplete your levels of vitamin D as it does with some other nutrients, explains Lauren Talbert, RD. 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. 

Speak to your health care professional 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. 

Do you need extra calcium during pregnancy?

Calcium 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 professional about how much calcium you should be getting in your diet. 

Why is choline important in pregnancy?

Choline is a nutrient similar to B vitamins. 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. You can get it from foods such as meat, fish, and multigrain. 

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 prenatal supplements.

“If the pregnancy is planned, it is ideal to start about three cycles (or months) before you are pregnant,” says Dr. Flanagan, OB-GYN. 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 Dr. Flanagan. 

What are the side effects of prenatal vitamins?

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

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 professional for support and information. 

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, OB-GYN 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. 

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 professional 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.

Do you really need prenatal vitamins?

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

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.