Background:Pregnant women with a Fontan circulation have a high risk of obstetric complications, such as preterm delivery and small for gestational age (SGA), which may be affected by low blood flow to the placenta and hypoxia. This study investigated placental pathology in a Fontan circulation.

Methods and Results:Eighteen pregnancies in 11 women with a Fontan circulation were reviewed. Pregnancy outcomes showed 9 miscarriages and 9 live births, with 4 preterm deliveries. Five neonates were SGA (<5th percentile). Eight placentas from live births in 7 women were available for the study. Five placentas had low weight placenta for gestational age, and 7 grossly showed a chronic subchorionic hematoma. Histological examination revealed all placentas had some form of histological hypoxic lesions: maternal vascular malperfusion in 7, fetal vascular malperfusion in 1, and other hypoxia-related lesions in 8. Quantitative analyses, including immunohistochemistry (CD31, CD68, and hypoxia inducible factor-1α antibodies) and Masson’s trichrome staining, were also performed and compared with 5 control placentas. Capillary density and the area of fibrosis were significantly greater in placentas from women with a Fontan circulation than in control placentas.

Conclusions:Placentas in a Fontan circulation were characterized by a high frequency of low placental weight, chronic subchorionic hematoma, and constant histological hypoxic changes, which could reflect altered maternal cardiac conditions and lead to poor pregnancy outcomes.

背景：有 Fontan 循环的孕妇发生产科并发症的风险很高，例如早产和小于胎龄儿 (SGA)，这可能会受到胎盘血流量低和缺氧的影响。本研究调查了 Fontan 循环中的胎盘病理学。

方法和结果：审查了 11 名患有 Fontan 循环的妇女的 18 次怀孕。妊娠结局显示 9 例流产和 9 例活产，其中 4 例早产。5 名新生儿为 SGA（<第 5 个百分位数）。来自 7 名妇女活产的 8 个胎盘可用于该研究。5 个胎盘具有低于胎龄的胎盘重量，7 个大体显示慢性绒毛膜下血肿。组织学检查显示所有胎盘都有某种形式的组织学缺氧病变：母体血管灌注不良 7 例，胎儿血管灌注不良 1 例，其他缺氧相关病变 8 例。定量分析，包括免疫组织化学（CD31、CD68 和缺氧诱导因子-1α抗体）和Masson三色染色，也进行了并与5个对照胎盘进行比较。

结论： Fontan 循环中的胎盘以高频率的低胎盘重量、慢性绒毛膜下血肿和持续的组织学缺氧变化为特征，这可能反映了母体心脏状况的改变并导致不良妊娠结局。