The day often ends with one last check of Instagram, a few minutes on YouTube or a scroll through messages before sleep. But what begins as a brief digital break can stretch late into the night, delaying bedtime and keeping the mind engaged when it should be winding down. Researchers are increasingly investigating whether this pattern of digital exposure, through its effects on sleep, may contribute to anxiety and other mental health difficulties among young people.

As World Mental Health Day is observed on October 10, emerging evidence suggests that the relationship between digital media and psychological well-being may depend not simply on how long people spend online, but also on when and how they use it.

A scoping review published in Computers in Human Behavior Reports in March 2026 examined longitudinal research on social media use and sleep among young people. The review found that approximately 70% of the longitudinal studies examined reported at least one negative association between social media use and sleep outcomes. The most consistent links involved later bedtimes and longer periods spent trying to fall asleep, particularly among those with problematic social media habits or who used platforms at bedtime.

The findings are significant because longitudinal studies track participants over time, helping researchers investigate whether digital habits precede subsequent changes in sleep. However, the authors cautioned that many studies relied on self-reported screen use and sleep patterns, limiting the strength of conclusions about cause and effect.

The review also identified an important distinction: total screen time alone did not consistently predict poor sleep. The timing of use and difficulty controlling online behaviour appeared to matter.

When sleep becomes the missing link

Sleep may help explain why certain patterns of digital engagement are associated with poorer mental health. Notifications, emotionally charged content and the pressure to respond immediately can keep users mentally alert. Scrolling in bed can also displace time that would otherwise be spent sleeping.

Insufficient or disrupted sleep can affect emotional regulation, concentration and the ability to manage everyday stress. For someone already experiencing anxiety, a poor night’s sleep may make worries more difficult to manage the following day. Repeated sleep disruption may then reinforce a cycle of distress and further digital engagement.

A systematic review and meta-analysis published in the Journal of Affective Disorders in December 2024 provides a broader picture of this relationship. Researchers assessed 182 studies involving 1,169,396 participants, with 98 studies and 102,683 participants included in the meta-analyses.

Representational image.Image credit:Pexels

The researchers found small but statistically significant associations between general social media use and anxiety and depression. Problematic social media use showed associations with anxiety, depression and sleep problems, alongside lower well-being. Importantly, ordinary social media use was not consistently associated with sleep problems or sleep duration, whereas problematic use was associated with sleep difficulties.

The relationship may also operate in both directions. People who struggle to sleep or experience anxiety may turn to their phones for distraction, reassurance or social connection. This can make it difficult to determine whether digital habits contribute to distress, whether distress encourages more digital engagement, or whether both are influenced by other factors.

Beyond the screen-time debate

The findings raise questions for families, schools, technology companies and public-health professionals. Advising young people to reduce screen time may be insufficient if it does not address bedtime habits, compulsive checking, online pressures and the reasons they turn to digital platforms in the first place.

Digital platforms can also provide friendship, information and mental health support. The challenge is to distinguish beneficial engagement from patterns that disrupt rest and emotional well-being.

As research advances, scientists will need to examine not only how much time young people spend online, but also what they experience there and how digital habits interact with sleep and existing vulnerabilities. The question is no longer simply whether people spend too much time on their phones. It is whether constant connectivity leaves enough room for the rest, recovery and emotional balance that mental health requires.

A study comparing brain scans across three major hormonal transitions finds shared patterns of structural change during puberty and pregnancy, while menopause follows a distinct trajectory.

The female brain undergoes different patterns of structural change during puberty, pregnancy and menopause, according to a study published in Nature Communications, highlighting how hormonal transitions may influence brain development and ageing across a woman’s life.

The research compared longitudinal brain imaging data from 1,095 participants. Researchers applied consistent analytical methods across three groups to investigate whether the hormonal transitions trigger similar or distinct changes in grey matter, the brain tissue involved in information processing.

The findings show that girls transitioning through menarche — the first menstrual period — and women going through pregnancy experienced widespread reductions in cortical grey matter volume. However, the patterns differed across brain regions. Women transitioning through menopause, meanwhile, showed no significant reduction in total or cortical grey matter volume during the study period, although women in the stable premenopausal and postmenopausal comparison groups showed declines.

The results suggest that these major hormonal transitions are associated with distinct patterns of brain remodelling rather than a single process affecting the female brain throughout reproductive life.

Puberty and pregnancy share some changes

The research team examined three cohorts: 142 participants in the puberty group, 110 in the pregnancy group and 843 in the menopause group. The researchers compared participants undergoing each transition with control groups to distinguish transition-related changes from ordinary developmental and age-related trajectories.

In the puberty cohort, 34 girls were assessed before and after menarche. Their brain scans showed significant monthly reductions in total and cortical grey matter volume, a pattern not observed in the stable premenarchal and postmenarchal comparison groups.

Similar changes appeared in women who became mothers. Both first-time and second-time mothers showed significant reductions in total and cortical grey matter volume compared with women who had not given birth. The study estimated monthly reductions of approximately 0.12% in total grey matter volume among first-time mothers and 0.11% among second-time mothers.

MRI Brain scans.Representational image.Image credit:Pexels

Despite these similarities, the researchers found that puberty generally involved greater cortical volume reductions than pregnancy. Their regional analysis covered 74 cortical regions and identified both shared and divergent patterns of change.

In 34 regions, the changes associated with puberty and pregnancy did not differ significantly from each other, while both showed greater reductions than the menopausal transition. These areas were concentrated in the prefrontal, parietal and temporal association cortices, which are involved in higher-order functions.

Other regions, particularly those associated with sensorimotor processing, showed a stepwise pattern in which the decline was greatest during puberty, followed by pregnancy and then menopause.

The authors caution that structural changes should not automatically be interpreted as evidence of damage. The study examined brain volume rather than directly measuring cognitive ability or the functional consequences of these changes.

Menopause presents a different pattern

The findings for menopause differed from those for puberty and pregnancy. Women who transitioned from premenopause to postmenopause during the study showed no statistically significant reduction in total or cortical grey matter volume. In contrast, the stable premenopausal and postmenopausal groups showed significant declines over their respective observation periods.

The researchers suggest that this pattern may indicate an attenuation of age-related volume decline during the menopausal transition itself. However, they stress that this interpretation remains preliminary, and the absence of a significant reduction does not establish that the brain undergoes no changes during menopause.

The study also has limitations. The three cohorts were drawn from different datasets and scanned using different MRI systems. Hormone measurements were not available in a harmonised format across all groups, preventing the researchers from directly comparing hormone levels with brain changes throughout the lifespan. Menarche and menopause were also classified using self-reported information rather than detailed clinical staging.

The findings add to a field in which women’s brain health, particularly during reproductive transitions, remains comparatively understudied. The authors call for future research combining repeated brain scans with hormonal, reproductive, psychological and social data.

By examining puberty, pregnancy and menopause within a common analytical framework, the study provides a more detailed picture of how structural brain changes vary across these transitions. It also underscores the need to investigate each stage separately rather than treating the female brain as following one continuous pattern of hormonal change.

Evidence from Tamil Nadu and a new international survey shows how rising temperatures threaten maternal and newborn health, with outdoor workers and rural women facing particular risks.

Extreme heat is emerging as a growing threat to pregnancy and childbirth, but climate adaptation plans risk overlooking the women and newborns most vulnerable to its effects. New international survey findings, alongside research from Tamil Nadu, point to a widening public-health challenge as rising temperatures threaten maternal health and expose inequalities in access to safe healthcare.

At least 73% of maternal healthcare professionals surveyed across five countries reported an increase in heat-related cases or complications affecting pregnant women over the past five years, according to a survey commissioned by global charitable foundation Wellcome. Meanwhile, 76% reported an increase in heat-related complications affecting foetal or newborn health.

The findings were highlighted by Simon Stiell, executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC), at an event organised by Wellcome during the Pre-COP ministerial meeting in Fiji on October 5, ahead of the COP31 climate conference in Türkiye in November.

“Rising temperatures mean rising danger in pregnancy,” Stiell said, pointing to links between extreme heat during pregnancy and premature birth, stillbirth, low birth weight and maternal complications.

The survey covered 1,000 maternal healthcare professionals working in Australia, Brazil, India, the United Kingdom and Zimbabwe. It found that 81% were concerned that extreme heat would increasingly threaten maternal, foetal and newborn health without further action. Nearly all respondents had cared for a pregnant woman or baby whose health they believed had been affected by extreme heat, while 92% wanted more training and resources to protect pregnant women.

The findings highlight a critical gap in climate preparedness: although heat-health warnings are becoming increasingly important, pregnancy and newborn care are not always adequately incorporated into plans for responding to extreme temperatures.

Evidence from India highlights unequal risks

Research from Tamil Nadu adds to the growing evidence that occupational heat exposure can have serious consequences for pregnancy.

A prospective cohort study published in BJOG: An International Journal of Obstetrics & Gynaecology examined 800 pregnant women engaged in moderate to heavy physical work in Tamil Nadu. Researchers found that 47.3% experienced high occupational heat exposure. Among heat-exposed women, 29.6% experienced moderate dehydration, while 17.4% recorded an increase in core body temperature.

The study found that women exposed to high occupational heat had 2.4 times the adjusted odds of miscarriage and 2.3 times the adjusted odds of an adverse pregnancy outcome. The latter included outcomes such as miscarriage, preterm birth, low birth weight and stillbirth.

Children are attending school in temporary learning centres following the devastating floods in Nuwakot, Nepal, where climate change and glacial ice melt have played a significant factor.Image credit: UNICEF/Laxmi Prasad Ngakhusi

The researchers also found that high occupational heat exposure was associated with twice the adjusted odds of an adverse outcome at birth. Although the study establishes an association rather than proving that heat alone caused each outcome, it provides evidence of the risks faced by pregnant women working in hot conditions.

A separate observational cohort study involving 680 pregnant women across six Tamil Nadu districts examined differences between rural and urban populations. Researchers found that 55% of rural participants experienced heat exposure above the study’s permissible limit, compared with 45% of urban participants.

Rural women were also more likely to report heat-strain symptoms, including excessive thirst, fatigue, headaches and dizziness. After accounting for potential confounding factors, heat-exposed rural women had nearly twice the risk of adverse pregnancy outcomes and three times the risk of adverse birth outcomes compared with the study’s urban comparison group.

The study also found a fourfold higher risk of miscarriage among heat-exposed rural women during the first trimester compared with urban women. The researchers identified socioeconomic disadvantage, limited awareness of heat risks and reduced access to welfare facilities as factors that could contribute to rural women’s greater vulnerability.

Evidence from a separate study of 126,273 pregnancies recorded in India and Pakistan reinforces the concern. Researchers found that higher average maximum temperatures during the second trimester were associated with an increased risk of preterm birth. The relative risk was 1.05 for the study’s five-degree temperature contrast, indicating a 5% relative increase in risk—not a five-percentage-point increase in the absolute risk of premature birth.

Together, these studies suggest that heat exposure is not simply an environmental inconvenience during pregnancy. It can coincide with dehydration, physically demanding work and barriers to healthcare, creating risks that are unevenly distributed across communities.

From warnings to protection

Stiell warned that the effects of extreme heat are not shared equally. Pregnant women who work outdoors, live in poorly ventilated housing, travel long distances to clinics or depend on healthcare facilities without reliable electricity, water or cooling cannot be protected through public advice alone.

“Staying cool” is not a realistic option for families without access to cool spaces, he argued. Without targeted intervention, extreme heat could deepen existing inequalities in maternal healthcare, making a safe pregnancy increasingly dependent on income, geography and access to medical services.

Stiell outlined three priorities for governments: integrating pregnancy and newborn care into climate adaptation and heat-health planning; translating evidence into practical protection through healthcare-worker training, heat alerts and safer facilities; and improving data to identify where risks are growing and which interventions are effective.

For India, the findings have implications for heat-action plans, occupational safety and maternal healthcare. Measures could include heat-risk guidance during antenatal visits, better protection for pregnant outdoor workers, improved ventilation and cooling in maternity facilities, and reliable access to water and electricity during extreme heat.

The UN climate chief also called for adaptation-finance commitments agreed at COP30 in Belém, Brazil, to be delivered and for countries to work towards mobilising $1.3 trillion annually for developing countries.

Health is expected to remain a key priority in preparations for COP31, scheduled for November 9–20, 2026, in Türkiye’s Antalya province, under the Turkish presidency and with Australia leading negotiations.

The emerging evidence makes the policy challenge clear: protecting pregnant women and newborns must become part of climate resilience, rather than an afterthought. As temperatures rise, governments will need to assess climate action not only by emissions targets and financial commitments, but also by whether healthcare systems can protect people during pregnancy and give newborns a safe start to life.