The evolutionary significance of placental interdigitation in mammalian reproduction: Contributions from comparative studies

I. Capellini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


The placenta is fundamental to mammalian reproduction and is surprisingly diverse in gross morphology among species. Whether and how this diversity affects maternal investment and fetal growth is still poorly understood. Contrary to suggestions that highly invasive hemochorial placentation is beneficial to fetal development, recent comparative studies have revealed that interdigitation - the degree of contact between maternal and fetal tissues at the area of exchange - strongly influences fetal growth rates. Species with labyrinthine placentae give birth to neonates of similar size to those of species with villous or trabecular placentae but in less than half the time. These findings suggest that there might be tradeoffs between fetal growth rates (higher with greater interdigitation) and gestation time (shorter with greater interdigitation), in association with type of interdigitation. Such tradeoffs might be the results of maternal-offspring conflict over the allocation of maternal resources, with paternal genes favouring greater interdigitation and so higher fetal growth, and maternal genes responding by reducing gestation time. These results emphasize the role of interdigitation as a means to increase the surface area for exchange, and are consistent with within species studies demonstrating that a higher surface area for exchange is associated with heavier neonates. Further studies could investigate the role of other traits in the evolution of placental diversity and their impact on fetal development.

Original languageEnglish
Pages (from-to)763-768
Number of pages6
Issue number10
Publication statusPublished - 01 Oct 2012

Bibliographical note

This review was invited by the journal Editor following the publication of my paper in American Naturalist (2010) and was peer reviewed


  • Comparative placentation
  • Evolution
  • Fetal development
  • Parent-offspring conflict
  • Phylogenetic comparative methods
  • Phylogeny

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynaecology
  • Developmental Biology


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