Mum Brain or Something More? Understanding the Link Between Sleep and Mental Fog

If you’ve been feeling forgetful, foggy, or mentally slower than usual, it’s easy to blame “mum brain.” It’s a term many women relate to — that sense of walking into a room and forgetting why, struggling to find words, or feeling like your brain just isn’t as sharp as it used to be. But while mum brain is real, it’s not always the full story.

What We Call “Mum Brain”

Mum brain is often linked to the changes that happen during pregnancy and early motherhood.¹ Hormonal shifts can affect memory, particularly verbal recall, making it harder to remember names, conversations, or small details.¹ On top of that, sleep becomes fragmented — whether it’s discomfort during pregnancy or frequent night waking after birth.¹

Together, these factors can lead to that familiar combination of forgetfulness, poor concentration, and mental fog. These changes are common and, for many women, temporary.

When It Might Be More Than Just Sleep Deprivation

Sleep deprivation is expected when you’re caring for a baby. But sometimes, the issue isn’t just how much sleep you’re getting — it’s the quality of that sleep.

This is where sleep apnea comes in. Sleep apnea is a condition where breathing repeatedly stops and starts during sleep due to the airway collapsing or becoming blocked.² These interruptions can happen dozens or even hundreds of times a night, often without you being fully aware of them.²

Pregnancy can increase the risk of sleep apnea due to natural changes in the body, including weight gain, hormonal effects on the airway, and increased blood volume leading to swelling in the upper airway.³

Why Poor Sleep Hits Your Brain So Hard

Your brain relies on deep, uninterrupted sleep to function properly. This is when memory is processed, attention is restored, and your mind resets for the next day.²

When sleep is repeatedly disrupted — whether from frequent awakenings or breathing interruptions — the brain misses out on this essential recovery time.² In the case of sleep apnea, reduced oxygen levels can further impact cognitive function.² The result? Persistent brain fog, difficulty concentrating, and that feeling of not quite being “on.”²

The Emotional Toll of Fragmented Sleep

Poor sleep doesn’t just affect thinking — it affects how you feel. When your brain is running on empty, you may notice yourself becoming more irritable, anxious, or easily overwhelmed.² Everyday tasks can feel harder than they should, and your capacity to cope can shrink.²

A Simple but Effective Treatment

If sleep apnea is the underlying issue, the good news is that it’s highly treatable. The most common treatment is CPAP therapy — a bedside device that gently blows air through a mask while you sleep.² This keeps the airway open, prevents breathing interruptions, and allows your body to get the deep, restorative sleep it needs.

When to Seek Help

If you’re experiencing ongoing brain fog, persistent fatigue despite spending enough time in bed, or symptoms like snoring or waking unrefreshed, it’s worth looking into further.

Mum brain may be common, but you don’t have to accept feeling constantly foggy or exhausted. Speaking to your doctor could help uncover what’s really going on — and getting the right support can make a meaningful difference to how you think, feel, and function each day.

How Sove CPAP Clinic Can Help

Founded in 2008, Sove CPAP Clinic has grown to become a leading provider of respiratory and sleep services and products in Australia, with over 90 clinics nationwide. Our comprehensive clinical team includes Respiratory & Sleep Specialists, Sleep Technologists, and CPAP Consultants, ensuring that you receive comprehensive and personalised care. All medical procedures, including sleep studies and lung function testing, are bulk billed to all Australians, with minimal wait time.

If you would like to speak to a Respiratory & Sleep Physician, book a bulk-billed sleep study, or seek advice for your sleep apnea, you can reach us at 1300 76 29 39 or info@thecpapclinic.com.au.

ALWAYS FOLLOW THE DIRECTIONS FOR USE. CPAP is used for Obstructive Sleep Apnea treatment. When considering whether a sleep study or CPAP is right for you, speak to your doctor. Medicare criteria and T&Cs apply.

References

1. OB/GYN, Cary. “Mum Brain Is Real: Why Mothers Become Forgetful after Giving Birth And What Can Help.” Cary OBGYN, 2021.

2. Suni, Eric, and Abhinav Singh. “Sleep Apnea.” Sleep Foundation, 2019.

3. “Sleep Apnea and Pregnancy — What Should You Know?” Weatherford Dental Sleep Medicine Blog, 2025.