Twin pregnancies involving assisted reproductive technology, particularly among older women, are considered to be high risk and vulnerable to chemical exposures. Per- and polyfluoroalkyl substances (PFAS) can cross the placenta and affect the fetus, but their transplacental transfer (TPT) is not well characterized for twin pregnancies. We employed a subset of twin pregnancies from the Ideal Breast Milk (IBM) cohort and measured the levels of PFAS and related chemicals in maternal (n = 78) and cord serum (n = 156) samples. L-PFOS and PFOA were detected at higher levels in maternal serum, with geometric means of 4.22 and 2.80 ng/mL, respectively, while the level of Br-PFHxS was higher in cord serum (0.29 ng/mL). Higher maternal PFAS levels were associated with the occurrence of maternal vascular malperfusion. Greater differences in cord PFAS levels between twin newborns were associated with higher maternal PFAS levels and an asymmetrical placental perfusion. The TPT ratio exhibited a U-shaped pattern with the number of carbons of PFAS, similar to a singleton pregnancy. Moreover, those with eight carbon atoms, i.e., 9Cl-PF3ONS, PFOA, and PFOS, showed different TPT efficiencies with respect to their structure and functional group. While the twin pregnancy does not appear to influence exposure levels or TPT efficiencies of PFAS and related chemicals, the consequences of the exposure warrant further investigations in this population.

中文翻译：

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韩国双胎妊娠队列中全氟烷基和多氟烷基物质的暴露和经胎盘转移


涉及辅助生殖技术的双胞胎妊娠，尤其是老年妇女，被认为是高风险的，容易受到化学品暴露的影响。全氟烷基和多氟烷基物质 （PFAS） 可以穿过胎盘并影响胎儿，但其经胎盘转移 （TPT） 在双胎妊娠中尚未得到很好的表征。我们采用了来自理想母乳 （IBM） 队列的双胞胎妊娠子集，并测量了母体 （n = 78） 和脐带血清 （n = 156） 样本中 PFAS 和相关化学物质的水平。在母体血清中检测到 L-PFOS 和 PFOA 的水平较高，几何平均值分别为 4.22 和 2.80 ng/mL，而脐带血清中 Br-PFHxS 水平较高 （0.29 ng/mL）。较高的母体 PFAS 水平与母体血管灌注不良的发生有关。双胞胎新生儿之间脐带 PFAS 水平的较大差异与较高的母体 PFAS 水平和不对称的胎盘灌注有关。TPT 比率呈现 PFAS 碳数的 U 形模式，类似于单胎妊娠。此外，那些具有 8 个碳原子（即 9Cl-PF3ONS、PFOA 和 PFOS）的 TPT 效率在其结构和官能团方面表现出不同的 TPT 效率。虽然双胎妊娠似乎不会影响 PFAS 和相关化学品的暴露水平或 TPT 效率，但暴露的后果值得在该人群中进一步调查。