Table 4 Associations between environmental chemicals and the maternal and neonatal thyroid hormone levels found in the Hokkaido cohort

 Maternal blood (2nd–3rd trimester)

Heel pick

(4.3 (median) days old)

Dioxin

358

FT4↑

FT4↑

PCBs and Non-ortho PCBs were positively associated with maternal FT4. Coplanar PCBs and Dioxin (TEQ) were associated with increased neonatal FT4, and the association was more significant among boys.

[40]

PCBs

386 mothers

410 neonates

FT4↑

FT4↑

OH-PCBs

222

FT4↑

FT4↑

Maternal OH-PCB levels were positively associated with maternal and neonatal FT4 levels.

[41]

OCPs

333

FT4↓

FT4↑

Maternal DDE, DDT, and dieldrin levels were inversely associated with maternal FT4, while maternal cis-nonachlor and mirex were positively associated with neonatal FT4.

[42]

PFOS and PFOA

392

TSH↓

TSH↑

Maternal PFOS levels were inversely correlated with maternal serum TSH and positively associated with infant serum TSH levels, whereas maternal PFOA showed no significant relationship with TSH or FT4 levels among mothers and infants.

[43]

DEHP

328

→

No association.

[44]

 Cord blood

Bisphenol A

285

→

No association.

[45]

 Maternal blood

(1st trimester)

Cord blood

PFAS

701

FT3↑, TPOAb↓

Boys: TSH ↑, FT3↓ [TA(+)]

TSH↓, TgAb↓[TA(−)]

Girls: FT4 ↓, TgAb↑ [TA(+)]

TSH↓, FT3↑[TA(−)]

Maternal PFAS levels were positively associated with maternal FT4 levels and inversely associated with maternal TPOAb.

Among boys, some maternal PFAS were associated with higher TSH, lower FT3 levels and TgAb maternal TA-negative group [TA(-)], while PFDA was associated with lower TSH in maternal TA-positive group [TA(+)].

Among girls, some PFAS of mothers showed associations with lower TSH and higher FT3 in maternal [TA(-)] , while PFDoDA was associated with lower FT4 and higherTgAb in maternal [TA(+)].

[46]