Читать книгу Genetic Disorders and the Fetus - Группа авторов - Страница 158

PHM is the result of triploidy, but is present in only a subset of diandric triploid pregnancies.¹³⁷ PHMs show some phenotypic overlap with CHMs on ultrasound assessment, but pathologically, exhibit a range of villi from normal to cystic villi with focal trophoblastic hyperplasia (Figure 4.1c, d).¹³⁸ Staining for p57 is preserved (normal). Although triploidy most commonly ends in miscarriage in the first trimester, PHM may be detected in a second‐trimester ultrasound where it presents as cystic placenta in association with an abnormally developed fetus, and may be associated with abnormal serum analytes (high hCG and α‐fetoprotein)^{139, 140} and PE.¹⁴¹ Diagnosis may be confirmed with chromosome testing by CVS or amniocentesis.