Did Pregnancy Shape the Human Brain?
Scientists from the University of Cambridge have introduced a fascinating idea: hormones produced during pregnancy especially sex hormones like estrogen and testosterone may have played a vital role in the evolution of the human brain. These hormones, created by the placenta, might have helped shape how our brains grew, how we think, and how we interact socially.
What Are Sex Hormones and Why Are They Important?
Sex hormones such as testosterone and estrogen are chemical messengers that control many body functions, including reproduction and brain development. During pregnancy, these hormones are mainly produced by the placenta (the organ that connects the mother to the baby and supports growth in the womb).
The Unique Role of the Human Placenta
The placenta doesn’t just deliver nutrients and oxygen. According to Dr. Graham Burton, co-author of the study, it also determines the duration of pregnancy and the rate of fetal growth. In humans, the placenta is more advanced than in other primates. The researchers believe that this may have contributed to our brains growing larger and more complex than those of other species.
Hormones in the Womb
Lead researcher Alex Tsompanidis suggests that high levels of sex hormones during pregnancy, combined with a highly functional placenta, may have allowed the human brain to become more connected and better developed. This could explain our species’ ability to learn language, form culture, and build communities.
Less Testosterone, More Cooperation
Interestingly, the team also found that lower levels of male sex hormones, such as testosterone, may have helped humans evolve to be less aggressive. This reduction in competition between males could have made it easier for early humans to live in larger, more peaceful social groups, which in turn improved survival and reproduction.
Hormones and Neurodiversity
Dr. Simon Baron-Cohen, a co-author and expert in autism research, explains that hormone levels in the womb also influence neurodiversity, which includes conditions like autism. Past studies show that sex hormones can affect early brain development. The new research goes further by proposing that these same hormones may have helped shape the way the human brain evolved over thousands of years.
Why This Matters
This new theory puts pregnancy and the placenta at the centre of human evolution. It suggests that the brain didn’t evolve in isolation, but was heavily influenced by changes in pregnancy biology, especially hormone production. As Tsompanidis puts it, “The human brain is remarkable and unique, but it does not develop in a vacuum.”
Conclusion
The researchers believe that understanding the role of pregnancy hormones could help explain why humans are so different from other animals in terms of thinking, learning, and social behaviour. As science continues to explore these early influences, we may find that the story of human evolution begins in the womb.
Source: Inputs from various media Sources
Priya Bairagi
Reviewed by Dr Aarti Nehra (MBBS, MMST)
I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.
