Related Experiment Video
Updated: Aug 13, 2026

Isolation of Leukocytes from the Murine Tissues at the Maternal-Fetal Interface
Published on: May 21, 2015
Sex differential of survival during perinatal period: an immunologic phenomenon?
The sex-differential early neonatal mortality experienced by a population of 27,243 neonates has been analyzed in relation to sex-related reproductive antecedents of their mothers. An association between the risk of dying of a neonate and the sex of previous pregnancies of its mother has been found: the risk decreases with a previous pregnancy of the same sex as the neonate, and increases with one of the opposite sex. Repeated pregnancies of same sex increase the phenomenon. An immunologic hypothesis has been formulated from these results: sex-differential survival of conceptuses during the perinatal period would be due to sex-differential conceptomaternal immunologic interactions. An advantage in survival of the female fetus results from these interactions in primiparous mothers. However, immunologic behavior of the mother is altered by previous contact with fetal antigens. Consequently sex-differential survival varies with sex-related antecedents of the gravida. Previous sensitization of the gravida by male pregnancy provides an advantage in survival for a subsequent male conceptus, and previous sensitization by female pregnancy provides an advantage in survival for a subsequent female conceptus.
The sex-differential early neonatal mortality experienced by a population of 27,243 neonates has been analyzed in relation to sex-related reproductive antecedents of their mothers. An association between the risk of dying of a neonate and the sex of previous pregnancies of its mother has been found: the risk decreases with a previous pregnancy of the same sex as the neonate, and increases with one of the opposite sex. Repeated pregnancies of same sex increase the phenomenon. An immunologic hypothesis has been formulated from these results: sex-differential survival of conceptuses during the perinatal period would be due to sex-differential conceptomaternal immunologic interactions. An advantage in survival of the female fetus results from these interactions in primiparous mothers. However, immunologic behavior of the mother is altered by previous contact with fetal antigens. Consequently sex-differential survival varies with sex-related antecedents of the gravida. Previous sensitization of the gravida by male pregnancy provides an advantage in survival for a subsequent male conceptus, and previous sensitization by female pregnancy provides an advantage in survival for a subsequent female conceptus.
More Related Videos
Related Concept Videos
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
The Y Chromosome Determines Maleness
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
Dosage Compensation
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
Transcytosis of IgG
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Development of Immunocompetence
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...
Immunodeficiency Diseases
There are three main causes of immunodeficiency disorders...

