Baby boy Cassian is an internet sensation. He was born earlier this year in the United States weighing 5.8 kilograms. But after his mum and the hospital shared the news recently, it wasn’t long before headlines about the “giant” baby spread around the world. These included:

‘Are you OK’?: Woman breaks record with giant newborn baby

Record-breaking baby tips the scales at almost double the average size of a newborn

While baby Cassian was born heavier than average, he’s not unique. There have been other examples in the news of babies born heavier. That includes a baby boy born in Brazil in 2023 who weighed 7.3kg.

These stories might make women all over the world cross their legs. But how common are big babies, and does their birth always lead to complications?

What are big babies?

Macrosomia describes babies born over 4kg or 4.5kg, depending on the definition.

A big baby can also be defined as having a birth weight over the 90th percentile at a particular gestational age. In other words, more than 90% of babies have a lower birth weight at this particular stage of the pregnancy. The term “large for gestational age” is probably a more accurate term as the weeks of gestation is used alongside the weight.

There has been little change overall in the percentage of large babies in the past decade in Australia. While stories of such births hit the media, their proportion hovers around 9–10% of births.

What are the problems for big babies and their mums?

We don’t know the specific circumstances of Cassian’s birth, his health or that of his mother. And we don’t know whether common reasons for larger babies are relevant in this situation.

But, generally speaking, birth complications can be higher for mothers and babies when the baby is big, especially if more than 4.5kg. This is certainly not always the case, however.

There is an increased need for interventions during the birth, such as forceps or vacuum delivery, or a caesarean section the bigger the baby is. Having these interventions can impact a women’s recovery after the birth, and options for the next birth.

For the baby there are higher risks of the shoulders getting stuck in the birth canal during the birth (known as shoulder dystocia).

Midwives and obstetricians also may need to make extra manoeuvres for the baby to be safely delivered. For instance, they may need to try and bring down one shoulder if it’s stuck behind the mother’s pubic bone.

These manoeuvres can damage the baby or lead to oxygen restrictions, with the baby needing to be resuscitated. However, these complications are rare and can occur when a big baby was not expected.

What leads to a big baby?

Big babies are most often healthy babies, and there are a number of reasons for them.

Genetic factors mean babies are always big in some families.

Babies that go over their due dates tend to be a bit bigger as they have more time to grow inside their mothers.

Having diabetes, especially if this is poorly controlled, can lead to larger babies. This is because the mother’s higher blood sugar leads to the baby receiving more energy than it needs, so it stores this extra energy as fat.

Babies of mothers with diabetes diagnosed for the first time in pregnancy (gestational diabetes) are at increased risk of being obese and developing diabetes in the future.

Mothers who are larger before pregnancy, or when pregnant, may also be more likely to have big babies. This is mostly due to the increased likelihood of developing diabetes in pregnancy, and perhaps poorer nutrition choices.

Can you predict a big baby?

Estimations of babies’ weights before they are born are imprecise. That’s why so many women are told they are going to have a big baby and don’t, and others are surprised by a big baby when it arrives.

Midwives and obstetricians routinely feel a woman’s growing uterus when they provide antenatal check-ups. They are looking at the position the baby is lying in the uterus as well as where the top of the uterus is compared to the woman’s belly button. This gives an idea of whether the baby is growing as you would expect at that time.

They also measure from the top of a woman’s belly to the top of her pubic bone with a tape measure. The weeks of pregnancy usually correspond to the measurement within a couple of centimetres.

For example, at 36 weeks of pregnancy the tape measurement would be somewhere between 34cm and 38cm. If there is more or less than a 3cm difference between the measurement and the numbers of weeks of pregnancy then an ultrasound would be offered to look at how the baby’s growing and to estimate the size.

But ultrasounds are poor predictors of actual birth weight. The Big Baby Trial was published earlier this year. It randomised nearly 3,000 women in the United Kingdom to being induced at 39 weeks if suspected to be having a big baby (according to an ultrasound) or waiting for labour to start.

There was little difference in birth weight or poor outcomes, such as shoulder dystocia for the baby, leading to the trial being stopped early. Around 60% of babies screened as being big babies were not actually big at birth, showing the inaccuracy of ultrasounds in predicting birth weight.

What can women do?

The best health advice for women is to try to be a healthy weight (under a BMI of 30) before getting pregnant.

Eat a balanced diet and limit your intake of foods and drinks high in saturated fats and sugar. Try not to put too much weight on during pregnancy and exercise regularly. Talk to your midwife or obstetrician for advice and support about this.

If you have diabetes, or if this has been diagnosed during the pregnancy, close monitoring of your blood sugar and baby’s growth is important.

Hannah Dahlen, Professor of Midwifery, Associate Dean Research and HDR, Midwifery Discipline Leader, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Children with traumatic experiences in their early lives have a higher risk of obesity. But as our new research shows, this risk can be reduced through positive experiences.

Childhood traumatic experiences are alarmingly common. Our analysis of data from nearly 5,000 children in the Growing Up in New Zealand study revealed almost nine out of ten (87%) faced at least one significant source of trauma by the time they were eight years old. Multiple adverse experiences were also prevalent, with one in three children (32%) experiencing at least three traumatic events.

Childhood trauma includes a range of experiences such as physical and emotional abuse, peer bullying and exposure to domestic violence. It also includes parental substance abuse, mental illness, incarceration, separation or divorce and ethnic discrimination.

We found children from financially disadvantaged households and Māori and Pasifika had the highest prevalence of nearly all types of adverse experiences, as well as higher overall numbers of adversities.

The consequences of these experiences were far-reaching. Children who experienced at least one adverse event were twice as likely to be obese by age eight. The risk increased with the number of traumatic experiences. Children with four or more adverse experiences were nearly three times more likely to be obese.

Notably, certain traumatic experiences (including physical abuse and parental domestic violence) related more strongly to obesity than others. This highlights the strong connection between early-life adversity and physical health outcomes.

Connecting trauma to obesity

One potential explanation could be that the accumulation of early stress in children’s family, school and social environments is associated with greater psychological distress. This in turn makes children more likely to adopt unhealthy weight-related behaviours.

This includes consuming excessive high-calorie “comfort” foods such as fast food and sugary drinks, inadequate intake of nutritious foods, poor sleep, excessive screen time and physical inactivity. In our research, children who experienced adverse events were more likely to adopt these unhealthy behaviours. These, in turn, were associated with a higher risk of obesity.

Despite these challenges, our research also explored a promising area: the protective and mitigating effects of positive experiences.

We defined positive experiences as:

• parents in a committed relationship
• mothers interacting well with their children
• mothers involved in social groups
• children engaged in enriching experiences and activities such as visiting libraries or museums and participating in sports and community events
• children living in households with routines and rules, including those regulating bedtime, screen time and mealtimes
• children attending effective early childhood education.

The findings were encouraging. Children with more positive experiences were significantly less likely to be obese by age eight.

For example, those with five or six positive experiences were 60% less likely to be overweight or obese compared to children with zero or one positive experience. Even two positive experiences reduced the likelihood by 25%.

How positive experiences counteract trauma

Positive experiences can help mitigate the negative effects of childhood trauma. But a minimum of four positive experiences was required to significantly counteract the impact of adverse events.

While nearly half (48%) of the study participants had at least four positive experiences, a concerning proportion (more than one in ten children) reported zero or only one positive experience.

The implications are clear. Traditional weight-loss programmes focused solely on changing behaviours are not enough to tackle childhood obesity. To create lasting change, we must also address the social environments, life experiences and emotional scars of early trauma shaping children’s lives.

Fostering positive experiences is a vital part of this holistic approach. These experiences not only help protect children from the harmful effects of adversity but also promote their overall physical and mental wellbeing. This isn’t just about preventing obesity – it’s about giving children the foundation to thrive and reach their full potential.

Creating supportive environments for vulnerable children

Policymakers, schools and families all have a role to play. Community-based programmes, such as after-school activities, healthy relationship initiatives and mental health services should be prioritised to support vulnerable families.

Trauma-informed care is crucial, particularly for children from disadvantaged households who face higher levels of adversity and fewer positive experiences. Trauma-informed approaches are especially crucial for addressing the effects of domestic violence and other adverse childhood experiences.

Comprehensive strategies should prioritise both safety and emotional healing by equipping families with tools to create safe, nurturing environments and providing access to mental health services and community support initiatives.

At the family level, parents can establish stable routines, participate in social networks and engage children in enriching activities. Schools and early-childhood education providers also play a key role in fostering supportive environments that help children build resilience and recover from trauma.

Policymakers should invest in resources that promote positive experiences across communities, addressing inequalities that leave some children more vulnerable than others. By creating nurturing environments, we can counterbalance the impacts of trauma and help children lead healthier, more fulfilling lives.

When positive experiences outweigh negative ones, children have a far greater chance of thriving – physically, emotionally and socially.

Ladan Hashemi, Senior Research Fellow in Health Sciences, University of Auckland, Waipapa Taumata Rau

This article is republished from The Conversation under a Creative Commons license. Read the original article.