Intrauterine position affects fetal weight and crown-rump length throughout gestation

Y. D. Jang, Y. L. Ma, M. D. Lindemann

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


To investigate the effect of intrauterine positions on fetal growth throughout gestation, data from a total of 65 gilts (n = 784 fetuses) that were slaughtered at assigned days of gestation (d 43, 58, 73, 91, 101, and 108) on a project to evaluate fetal mineral deposition were used. Placenta units were removed from the uterus, and position, sex, weight, and crown-rump length (CRL) of each fetus were recorded. Fetuses were classified into 5 categories within a uterine horn for the absolute intrauterine position: the ovarian end (OE) of the uterine horn, next to the ovarian end (NOE), the middle (MD), next to the cervical end (NCE), and the cervical end (CE), and also classified for the relative fetal position with respect to the sex of adjacent fetuses. Fetuses at the OE and NOE of the uterine horn tended to be heavier (P = 0.06) and longer (P < 0.05) than those at the MD of the uterine horn at d 58 of gestation. Fetuses at the OE of the uterine horn were also heavier and longer than those at the MD and NCE of the uterine horn at d 101 and 108 of gestation (P < 0.05). Fetuses at the CE of the uterine horn were intermediate in weight and length. There were no major effects of adjacent fetal sex (fetuses surrounded by the opposite sexes) in weight or length. Male fetuses were heavier than female fetuses at d 43, 58, 73, and 108 of gestation (P < 0.05) and longer than female fetuses at d 58 (P = 0.06), 73 (P < 0.05), 101 (P = 0.07), and 108 (P < 0.05) of gestation. Fetal weight was highly correlated with CRL at all gestational ages (P < 0.01). These results indicate that 1) the absolute intrauterine position affects fetal growth more than the sex of the adjacent fetus in the uterine horn, 2) each end of the uterine horn (OE and CE) has heavier fetuses than the MD, and 3) male pigs grow faster than female pigs even before birth.

Original languageEnglish
Pages (from-to)4400-4406
Number of pages7
JournalJournal of Animal Science
Issue number10
StatePublished - Oct 1 2014

Bibliographical note

Publisher Copyright:
© 2014 American Society of Animal Science. All rights reserved.


  • Crown-rump length
  • Fetal weight
  • Gestation day
  • Intrauterine position

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics


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