Are mothballs safe during pregnancy?

What does the evidence say about mothballs during pregnancy?

1. Naphthalene, the active ingredient in traditional mothballs, crosses the placenta, and case reports describe the fetus as apparently more vulnerable to its effects than the mother. 1
2. Infants, especially those with glucose-6-phosphate dehydrogenase (G6PD) deficiency, are particularly sensitive to naphthalene, and cases of hemolytic anemia progressing to kernicterus or death have been reported in infants exposed to naphthalene from household items stored with mothballs. 1
3. Naphthalene's toxic effect comes from a surge of free oxygen radicals that damage red blood cells, a process that G6PD-deficient cells can't buffer well because they produce less of the antioxidant their metabolism depends on. 2
4. A pregnancy-only case of naphthalene dependence describes a woman drawn to the smell of mothballs throughout pregnancy, with the craving resolving immediately after delivery. Naphthalene and its breakdown products cross the placenta, and newborns are more susceptible to its oxidative effects because of their thinner skin and lower glutathione stores. 3
5. Indoor naphthalene levels can run up to 100 times higher wherever mothballs are used, which is part of why WHO's indoor air quality guidelines call for phasing out naphthalene-containing mothballs altogether. 4

Is mothballs safe in each trimester?

• First trimester. If you find clothing or blankets stored with mothballs early in pregnancy, this is the point to switch storage methods, since naphthalene vapor builds up in closed closets, drawers, and storage boxes with no established safe exposure level for pregnancy.
• Second trimester. Continued exposure through mid-pregnancy carries the same placental-crossing concern as earlier, and it adds up: case reports describe symptoms following repeated exposure over time, not just a single whiff.
• Third trimester. Exposure closest to delivery is when documented newborn harm has actually occurred, since naphthalene and its breakdown products reach the baby's bloodstream directly. If you've stored baby clothes or bedding with mothballs, wash and air out those items well before your due date.