Lead and Cadmium in Pregnancy Linked to Lower Birth Weight
NonToxCo Research
Science & Safety Team · 4/7/2026
Lead and cadmium exposure during late pregnancy were directly linked to lower birth weight. The effects are real, measurable, and dose-dependent.
What the Study Found
A 2026 study in J Korean Med Sci tracked heavy metal levels in pregnant women from the Korean Mother-Child Environmental Health cohort. They measured lead (Pb), cadmium (Cd), and mercury (Hg) in both early and late pregnancy.
Late-pregnancy lead exposure was associated with 15.5 grams lower birth weight. Late-pregnancy cadmium was linked to 24.2 grams lower birth weight. These are direct effects that remained after adjusting for other factors.
Early Exposure Works Through Late Exposure
Lead in early pregnancy didn't directly affect birth weight. But it predicted lead levels in late pregnancy, which then reduced birth weight. The pathway was indirect: early lead leads to continued exposure, which accumulates, which lowers the baby's weight.
Gestational weight gain also played a role as a mediator. Mercury showed a complicated pattern where different pathways canceled each other out.
Where Lead and Cadmium Come From
Lead comes from old pipes, paint in pre-1978 housing, contaminated soil, and some imported products. Cadmium comes from cigarette smoke (even secondhand), rice, leafy vegetables, and shellfish. Both metals cross the placenta easily.
How to Protect Your Baby
Filter your water. Test your home for lead paint. Don't smoke and avoid secondhand smoke. Eat a varied diet to reduce cadmium from any single food source. Check out non-toxic baby products for a safer environment from birth.
Also see glass food storage for safer alternatives.