Written by the Progyny Editorial Team. Reviewed by the Progyny Clinical Team — November 2025.
When you’re pregnant, you want to do everything you can to keep your growing baby safe. There’s a lot of advice about what to avoid eating, drinking, or putting in your body, and it can get confusing.
Let’s walk through which substances to limit or avoid for a healthy pregnancy.
Mercury in seafood
Some fish and seafood are high in mercury, a type of metal that can cross the placenta when you’re pregnant. This means when you eat food high in mercury, mercury will end up in your baby’s body.
High amounts of mercury are dangerous for your growing baby. It can harm their developing brain and nervous system, and may lead to birth defects.
Use this guide to find out which types of seafood are good choices during pregnancy, and which should be avoided.
| ✅ Good (low in mercury) | 🚫 Avoid (high in mercury) |
|---|---|
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Before eating locally caught fish or seafood, check the local fish advisories. Levels of mercury (and other metals and toxins) are affected by seasons and local events. These advisories will let you know if local catches are safe to eat.
For more information, the Food and Drug Administration offers a detailed guide about eating fish during pregnancy.
Vitamins and supplements
It’s recommended that you take prenatal vitamins during pregnancy.
However, some other vitamins and supplements (like megavitamins and herbal supplements) may:
- Be harmful to the baby
- Cause side effects
- Make your blood sugar go up or down
- Prevent other medicines from working
Be sure to tell your healthcare provider about everything you take, including vitamins, supplements, and over-the-counter medicines. Your provider will make sure it’s safe for you and your baby.
Caffeine
Having up to 200 mg of caffeine a day is considered safe when you’re pregnant. High amounts of caffeine could increase the risk of pregnancy loss or preterm birth. To be safe, aim for less than 200 mg a day. This is about the amount in 12 ounces (1.5 cups) of coffee, depending on the strength.
But talk to your doctor about what they recommend for you. For some people (including if you have diabetes or gestational diabetes), it may be best to avoid it. This is because caffeine may make your blood sugar rise or drop.
Sodium
Too much sodium (salt) can cause high blood pressure for some people — and that’s a risk during pregnancy. Limiting your sodium intake can help reduce your chances of high blood pressure.
Doctors recommend having no more than 2,300 mg of sodium a day. Major sources of sodium include packaged and prepared foods like:
- Sandwiches
- Pizza
- Canned soups
- Frozen dinners
- Chips and crackers
- Condiments and sauces
Alcohol, smoking, and recreational drugs
There is no safe amount of alcohol, tobacco, or recreational drugs during pregnancy.
These substances can cause:
- Growth and developmental problems for your baby
- Miscarriage
- Stillbirth
- Premature delivery
- Blood sugar changes for you
For help stopping any of these, it’s absolutely OK to speak with your healthcare team. They can help you quit and will be happy to help. It’s the best thing you can do for your little one.
We know there are a lot of do’s and don’ts when you’re pregnant. To learn more about food safety, check out:
You can talk to your Progyny Care Advocate any time you need a little extra help sorting through it all.
Disclaimer: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance.