“To call woman the weaker sex is a libel; it is man's injustice to woman.”
—Mahatma Ghandi, 1930
Women are like superheroes, with powers of physical transformation that enable the phenomenal feat of reproduction. Without them, our species would perish.
To think of women as the weaker sex is to deny their superpowers. To refer to their physical transformations during pregnancy, childbirth and lactation as somehow representing vulnerability is to deny biological reality.
The changes that occur in a woman’s body in preparation for, during and after pregnancy are a marvel of evolution. At some point in our history there was an advantage to conception occurring inside the female body, rather than having males and females scatter millions of sperm and eggs into the environment and leave their meetings to chance. Then, rather than expelling fertilised eggs into nests, natural selection favoured protecting the developing baby inside the female body. To achieve this, the female immune system had to develop ways to facilitate implantation of the embryo within the uterus and accommodate the developing fetus, whose genetic differences from the mother could otherwise result in rejection.
‘Listeria hysteria’ is a term that is familiar to many of us. Most new mums have probably heard of listeria, an infection that you can get from eating the ‘wrong’ foods in pregnancy and the resulting illness, listeriosis. It’s a well established fact that avoiding soft cheeses and other foods that can harbour the bacteria (Listeria monocytogenes) that causes the disease is the best way to minimise risk, but there are some myths and misconceptions about this and other infections during pregnancy, and how they relate to the maternal immune system.
The myth that pregnancy is an ‘immunocompromised’ state is obviously incorrect. What kind of evolutionary process would place members of a species at increased risk at the exact same time that they were reproducing? It doesn’t make sense.
The immune system in pregnancy is different than it is at other times of a woman’s life. It changes to protect not just the mother, but her fetus too. The developing baby relies on her mum’s protection from bacteria, viruses and other nasty things just as she relies on her mum for nutrients and oxygen. And just as the placenta mediates nutrition and gas exchange for the fetus, it mediates immune function. The cells of the immune system that reside in the placenta are different in number and function than in other organs. These cells help with conception and for the embryo to implant, for the placenta to form properly, to protect the fetus from infections, and probably for birth to occur.
Some bacteria and viruses do seem to target the placenta and fetus, though. Some infections can cause profound abnormalities in development, stillbirth, preterm birth and/or newborn illness. Taking sensible precautions to avoid the devastating consequences of some infections makes good sense. All women should talk to their care providers about minimising risks from infections.
There’s a misconception that pregnant women are, generally, more at risk of infections than everyone else. In actual fact, "The evidence of increased susceptibility of pregnant women to infection is rather weak". We’re more likely to notice infections in pregnant women and babies than in many other groups in our communities. And although some infections might be more severe in pregnant women than others (like the flu), this might not be because of the immune system at all. The normal changes in a woman’s body that occur in pregnancy, like lower lung volume as the fetus grows, alterations in blood flow and fluid balance, might mean that infections have a greater impact in pregnancy than at other times.
The changes in women’s bodies that occur before, during and after pregnancy should be celebrated for the natural marvels that they are. Pregnancy and childbirth exemplify women’s strength, not vulnerability.
Associate Professor Tim Moss, PhD