Mercury Fillings and Pregnancy: What the FDA Says and What to Actually Do

If you are pregnant or planning to become pregnant and you have amalgam fillings, you have likely searched for guidance — and found conflicting information. Here is what the actual regulatory guidance says, what it means in practice, and what questions to bring to your healthcare providers.

What the FDA actually recommends

In September 2020, the FDA updated its guidance on dental amalgam and issued specific recommendations for certain groups. For pregnant women, the guidance states that mercury amalgam should be avoided whenever possible and that alternative restorative materials should be used instead for any new cavities requiring treatment.

This was a significant update. Previous FDA guidance had treated amalgam as safe for the general population without population-specific carve-outs. The 2020 update explicitly acknowledges that the risk profile is not uniform and that certain groups — including pregnant women — warrant a more cautious approach.

The FDA guidance applies to new amalgam placement. It does not recommend routine removal of existing stable fillings during pregnancy.

Why pregnancy changes the equation

Mercury crosses the placenta. This is established biology, not speculation. The developing fetus is exposed to mercury from maternal blood, including mercury vapor absorbed from amalgam fillings. Fetal and infant neurological development is more sensitive to mercury exposure than adult neurological function — which is why pregnant women, nursing mothers, and young children are consistently identified as higher-risk groups in mercury-related guidance.

Mercury is also present in breast milk. Nursing mothers are included in the same FDA guidance category as pregnant women for this reason.

None of this establishes that existing amalgam fillings in pregnant women cause specific, measurable harm to the fetus at typical exposure levels. The evidence on that specific question is limited. What it does establish is a clear precautionary rationale for the guidance: given that mercury-free alternatives exist and work well, there is no reason to introduce new amalgam exposure during pregnancy.

What to do about existing fillings during pregnancy

The guidance from most clinical organizations is consistent: do not schedule elective amalgam removal during pregnancy.

The reason is the removal paradox discussed in our SMART protocol guide: removing an amalgam filling temporarily exposes you to significantly more mercury than leaving a stable filling in place. During pregnancy, that short-term spike may be more concerning than the ongoing low-level exposure from stable fillings.

What this means in practice:

• Stable, intact fillings — leave them in place during pregnancy. Monitor but do not schedule elective removal.
• Failing fillings that must be addressed — if a filling is cracked, leaking, or has recurrent decay and genuinely needs treatment during pregnancy, discuss timing with your OB-GYN. The second trimester (weeks 14–28) is generally preferred for non-emergency dental work. Use composite resin for replacement, not amalgam.
• Emergency dental work — dental emergencies are treated as needed regardless of trimester, using the safest available materials.

If you want removal done before pregnancy

Many patients who are planning pregnancy choose to have amalgam removal completed before conceiving. This is a reasonable approach that eliminates the source of ongoing exposure before the pregnancy begins, without exposing a developing fetus to the short-term removal spike.

If this is your plan:

• Complete removal at least 1–3 months before attempting conception — this allows time for the temporary exposure from removal to clear
• Use a SMART-certified dentist to minimize the exposure during removal itself — this matters even more given your pre-conception timing goal
• Coordinate with your OB-GYN so they are aware of the timing and can note it in your prenatal record

Use our appointment checklist to evaluate any dentist you're considering for pre-pregnancy removal, and our provider directory to find SMART-certified options near you.

New cavities during pregnancy

Pregnancy increases cavity risk — hormonal changes affect saliva composition and gum health, and morning sickness can introduce stomach acid into the mouth. If you develop a cavity during pregnancy that needs filling, the recommended material is composite resin, not amalgam.

This is now mainstream dental practice. Most dentists are comfortable with composite for all restorations during pregnancy. If your dentist suggests amalgam for a new filling during pregnancy, it is entirely appropriate to ask for composite instead, citing the FDA's 2020 guidance.

For information on composite as a replacement material, see our composite vs amalgam comparison. For material safety considerations more broadly, Dental Material covers biocompatibility research in depth.

Questions to bring to your providers

Bring these questions to both your dentist and your OB-GYN before making any decisions:

• Are any of my existing amalgam fillings failing or at risk of needing replacement during my pregnancy?
• If I need dental work during pregnancy, what material do you recommend?
• If I am planning pregnancy, what is your recommendation on timing for elective amalgam removal?
• How will we communicate about dental work and timing during my pregnancy?

Key Takeaways

• FDA's 2020 guidance recommends against new amalgam placement in pregnant women and nursing mothers
• Elective removal of stable fillings during pregnancy is generally not recommended — removal increases short-term exposure
• Failing fillings that need treatment during pregnancy should be replaced with composite, not amalgam
• If you want removal done before pregnancy, complete it 1–3 months before attempting conception
• New cavities during pregnancy should be filled with composite resin
• Coordinate dental decisions with your OB-GYN throughout pregnancy

This article is for educational purposes only and does not constitute medical or dental advice. Decisions about dental treatment during pregnancy should be made in consultation with both your dentist and your obstetric provider.