Fetal macrosomia in South Kivu, Democratic Republic of the Congo: prevalence, risk factors, and neonatal outcomes

Every baby begins life with a weight that tells a story about their mother's health and the environment in which they grew. In the world of medicine, a baby born weighing four kilograms or more is considered to have fetal macrosomia, a condition where the infant is significantly larger than average. While a larger baby might seem like a sign of robust health, this extra size often carries hidden risks. For the mother, it can make delivery difficult and dangerous; for the newborn, it can lead to breathing problems, low blood sugar, and a higher chance of injury during birth. In wealthy nations, doctors have long tracked these trends, linking them to rising rates of obesity and diabetes. However, in many parts of the world, particularly in low-resource settings, the full picture of how often these large babies are born, why they are born, and what happens to them afterward remains unclear.

In the eastern Democratic Republic of the Congo, a region known for its complex health challenges, a team of researchers set out to fill this gap. They focused their attention on South Kivu province, an area where access to advanced medical care can be scarce. The team wanted to understand the scale of the problem: how many babies were being born with this excessive weight, what factors in the mother's life were driving it, and how these babies fared after they were born. By looking at records from ten different hospitals and health centers, ranging from busy urban clinics to rural facilities, they gathered a clear snapshot of reality for over one thousand mother-and-baby pairs.

The researchers examined data collected between May and September 2023, reviewing the records of every full-term birth that occurred in their selected facilities. They were looking for a specific threshold: any baby weighing four thousand grams or more. Out of the 1,247 full-term births they analyzed, they found 87 babies who met this criteria. This meant that roughly seven out of every hundred babies born in these facilities were macrosomic. This rate is similar to what has been seen in other parts of sub-Saharan Africa, but it is lower than the rates often reported in high-income countries. The difference likely reflects the varying nutritional landscapes and healthcare systems across the globe.

To understand why these babies were so large, the team looked closely at the mothers. They considered many possibilities: the mother's age, how many children she had already given birth to, her level of education, and whether she had any infections or complications during pregnancy. At first glance, older mothers and those who had given birth many times before seemed more likely to have a large baby. However, when the researchers used statistical tools to separate these factors from one another, a different picture emerged. The only factor that stood out as a true, independent cause was the mother's body weight. Specifically, mothers who were obese were more than twice as likely to have a macrosomic baby compared to mothers with a normal weight. Other factors, such as the number of prenatal visits a mother attended or her marital status, did not show a direct link to the baby's size once the mother's weight was taken into account.

The consequences of having a large baby were stark and immediate. The study revealed that these newborns faced a much harder start to life. Babies born with macrosomia were nearly nine times more likely to die before leaving the hospital compared to babies of normal weight. They were also more than three times as likely to require intravenous feeding, a sign that they were too weak or unwell to feed on their own. These findings highlight that the danger is not just in the size of the baby, but in the fragility that often accompanies it in a setting where advanced neonatal care is limited. The extra weight seems to predispose these infants to severe complications that can be fatal without intensive medical support.

The researchers noted that while older mothers and those with many previous births did have larger babies in the raw numbers, this was likely because these groups also had higher rates of obesity. In other words, the mother's weight was the driving force behind the size, rather than her age or birth history alone. This distinction is crucial because it points to a specific, manageable target for health interventions. If the goal is to reduce the number of dangerous large babies, the focus must be on managing maternal obesity before and during pregnancy.

This study serves as a vital warning and a guide for the future in a region where data is often scarce. It confirms that fetal macrosomia is a significant public health issue in South Kivu, affecting a notable portion of births and carrying a heavy toll on newborn survival. The link to maternal obesity suggests that the solution lies in better nutritional care and weight management for pregnant women. By identifying the mothers at highest risk early and providing them with the right support, health workers in the Democratic Republic of the Congo could potentially prevent many of the tragic outcomes associated with these oversized births. The path forward requires a shift in how pregnancy is monitored, moving beyond simple check-ups to actively addressing the weight and health of the mother to ensure the safety of the child.