A new study in pre-clinical models has discovered a link between low oxygen in the womb and impaired memory function. It also finds that anti-oxidant supplements during pregnancy may protect against this.

The study shows that preventative medicine could be used before birth to protect long term brain health. Hudson Institute senior research scientist in neurodevelopment and neuroprotection, Dr Emily Camm is the first author of the study, published in the journal FASEB J.

Key points

• Low oxygen in the womb – known as chronic fetal hypoxia – is one of the most common complications in pregnancy
• Is caused by a number of conditions including pre-eclampsia, infection of the placenta, gestational diabetes or maternal obesity
• Chronic fetal hypoxia can adversely affect how a baby’s brain develops.

The new study shows that chronic fetal hypoxia leads to a reduced density of blood vessels, and a reduced number of nerve cells and their connections in parts of the developing brain.

In adulthood, this results in a reduced ability to form lasting memories and there is evidence of accelerated brain ageing.

Vitamin C, an anti-oxidant used in the study was shown to protect future brain health in the pre-clinical models.

“It’s hugely exciting to think we might be able to protect the brain health of an unborn child by a simple treatment that can be given to the mother during pregnancy,” said Dr Camm who performed the study in collaboration with Cambridge University’s Department of Physiology, Development and Neuroscience in the UK.

The researchers used vitamin C because it is a well-established and commonly used anti-oxidant. However, only high doses were effective, which could cause adverse side effects in humans. Follow-up studies are now searching for alternative anti-oxidants that would be suitable to treat chronic fetal hypoxia in humans.

In analysis, the scientists showed that hypoxic pregnancy causes excess production of reactive oxygen species, called ‘free radicals’, in the placenta. In healthy pregnancy the body keeps the level of free radicals in check by internal anti-oxidant enzymes, but excess free radicals overwhelm these natural defences and damage the placenta in a process called ‘oxidative stress’. This reduces blood flow and oxygen delivery to the developing baby.

In this study, placentas from the hypoxic pregnancies showed oxidative stress, while those from the hypoxic pregnancies supplemented with vitamin C looked healthy.

Taken together, these results show that low oxygen in the womb during pregnancy causes oxidative stress in the placenta, affecting the brain development of the offspring and resulting in memory problems in later life.

“Chronic fetal hypoxia impairs oxygen delivery at critical periods of development of the baby’s central nervous system,” said Dr Camm. “This affects the number of nerve connections and cells made in the brain, which surfaces in adult life as problems with memory and an earlier cognitive decline.”

The interaction between our genes and lifestyle plays a role in determining our risk of disease as adults. There is also increasing evidence that the environment experienced during sensitive periods of fetal development directly influences our long-term health – a process known as ‘developmental programming.’

Brain health problems that may start in the womb due to complicated pregnancy range from attention deficit hyperactivity disorder, to brain changes in later life that have been linked with Alzheimer’s disease.

“In medicine today there has to be a shift in focus from treatment of the disease, when we can do comparatively little, to prevention, when we can do much more. This study shows that we can use preventative medicine even before birth to protect long term brain health,” said Professor Dino Giussani from the University of Cambridge’s Department of Physiology, Development and Neuroscience, who collaborated with Dr Camm on the study.

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