Placental Pathology

About the Program

"Maternal-fetal medicine is the only specialty in medicine in which there are two hosts. Generally, they should have the same interests, but with the introduction of insults, the interests are often divergent."
Dr. Roberto Romero

The placenta is considered to be the largest human biopsy, and some have proposed that it is a “diary” of intrauterine life. Placental dysfunction, often referred to as placental insufficiency, has been implicated as a major cause of the “Great Obstetrical Syndromes” (including preeclampsia, fetal growth restriction, fetal death, preterm labor, macrosomnia, preterm PROM, among others) and disorders such as placenta accreta spectrum. We study the human placenta to understand the pathologic basis of complications of pregnancy.

The Placental Pathology Unit of the PRB aims to characterize the prevalence, distribution patterns, and clinical significance of histopathologic lesions of the placenta. This Unit was created to investigate a major gap of knowledge; the significance of lesions identified during surgical pathologic examination of the human placenta.

We have studied the occurrence of placental pathology lesions in normal and complicated pregnancy and have used conventional histologic techniques, as well as the tools of molecular pathology. Examples include laser microdissection microscopy, electron microscopy, and single-cell spatial transcriptomics.



  • To determine the frequency, distribution patterns, and biological significance of histopathologic lesions of the placenta
  • To understand placental development and placental lesions by using the techniques of molecular pathology

Research Highlights

  • Determine the frequency of placental lesions in patients with normal pregnancy outcomes.
  • Studied the frequency, severity, clinical relevance, microbiology, and inflammatory responses as well as the neonatal and long-term outcomes in patients with acute histologic chorioamnionitis and funisitis
  • Elucidation of the pathway of ascending infection by demonstrating that microbial invasion of the amniotic cavity is initiated by a discrete, localized bacterial invasion of the chorioamniotic membranes, a process followed by intra-amniotic proliferation that extends to the chorioamniotic membranes
  • Description, prevalence, and clinical significance of funisitis, a hallmark of the fetal inflammatory response syndrome
  • The first description of fetal congenital dermatitis as a possible component of the fetal inflammatory response syndrome
  • Description, prevalence, and clinical significance of chronic inflammatory lesions of the placenta
  • Evidence supporting that acute chorioamnionitis and chronic chorioamnionitis represent different pathological subsets of the preterm parturition syndrome: acute chorioamnionitis is associated with microbial-associated intra-amniotic inflammation, also known as sterile intra-amniotic inflammation, and chronic chorioamnionitis is associated with maternal anti-fetal rejection
  • Demonstration of villitis of unknown etiology as a unique condition that presents the combined features of maternal anti-fetal rejection and graft-versus-host disease
  • Determination of the association between the failure of physiological transformation of the spiral arteries and a subset of spontaneous preterm labor and birth
  • Demonstration of functional compartmentalization of the human placental amnion and reflected amnion
  • Description of the role of microRNAs in human parturition and pregnancy disorders
  • Characterization of the transcriptome of the chorioamniotic membranes in term parturition
  • Description of placental histological lesions as well as cytokine and chemokine profiles in the maternal and fetal plasma of women with clinical chorioamnionitis at term
  • Studies of disorders of villous maturation and their association with chronic fetal hypoxia and fetal death as well as with preterm labor

Select Publications



Sunil Jaiman, M.D.

Section Head, Placental Pathology Unit, Wayne State University Perinatal Initiative in support of the Perinatology Research Branch, NICHD/NIH/DHHS