I have a theory about why infant mortality rates were so high in the past.

I have a theory about why infant mortality rates were so high in the past. I remember learning that many babies died during childbirth, and that was one of the reasons the woman who helped establish Mother’s Day wanted to train mothers on proper infant care. Child mortality was extremely high at the time.

In the mid-19th century, childbirth was very risky. Many women died from infections after giving birth. A major cause was the lack of understanding about germs. Doctors and assistants often did not wash their hands or instruments after performing dissections or autopsies before assisting with births. This spread infections such as puerperal (childbed) fever.

Advocates like Ignaz Semmelweis demonstrated that handwashing dramatically reduced infection rates—sometimes to as low as 1–2%. However, much of the medical community initially rejected his findings. Midwives, who were typically not involved in surgical procedures or autopsies, often had lower infection rates in many places. Births attended by midwives frequently occurred at home and did not involve the same hospital-based exposures. Midwives also commonly supported side-lying birth positions, which can reduce the risk of tearing, although tearing can still occur if, for example, the baby’s head is large.

By the early 20th century, as obstetrics became more professionalized and births increasingly shifted to hospitals, outcomes gradually improved due to antiseptic techniques, prenatal care, antibiotics, and emergency interventions.

My theory is this: if doctors did not wash their hands after handling cadavers and then examined a woman during labor or handled a newborn, they could have transmitted deadly infections to both the mother and the baby. Newborns have immature immune systems, making them especially vulnerable to infection. It is possible that some babies died not only because their mothers became infected, but because they themselves were directly exposed to bacteria introduced during delivery.

I also wonder whether cousin marriages, which were more common in some communities in the past, may have contributed in certain cases. Close-relative marriages can increase the risk of genetic disorders, some of which may weaken the immune system or increase early mortality. If a baby already had a genetic vulnerability and was then exposed to bacteria during birth, that combination could have increased the risk of death.

So my overall theory is that high infant mortality may have resulted from a combination of factors: poor hygiene practices in medicine, lack of germ theory, limited medical knowledge, and in some cases genetic vulnerabilities due to close-relative marriages. A lack of medical understanding at the time likely contributed significantly to these tragic outcomes.