More than 5% of cases of sudden infant death may be linked to maternal obesity, new research showed.
Nowadays, half of women in reproductive age are overweight or obese. Obesity affects many aspects related to pregnancy, such as placental development and gene expression, and has long-term implications.
Maternal obesity is a recognized risk factor for negative pregnancy outcomes, such as stillbirth, preterm birth, and neonatal intensive care unit admissions. In 2014, Swedish researchers found that higher maternal BMI was associated with a rise in infant mortality rates. However, that study did not specifically examine the connection to sudden unexpected infant death (SUID).
Rates of SUID in babies born to mothers with obesity increased in a statistically significant, dose-dependent manner relative to normal weight mothers. The unadjusted absolute risks for SUID were 0.74 cases per 1000 births for normal weight mothers, 0.99 cases at BMIs between 30 and 35, 1.17 cases at BMIs between 35 and 40, and 1.47 instances at BMI ≥ 40. After adjustment for maternal age, race, ethnicity, and level of education, the adjusted odds ratio for a case of SUID was 1.39 among women with the highest levels of obesity (95% CI, 1.31-1.47), according to the researchers.
The study identified a link between maternal obesity and SUID, but the underlying reasons for this connection remain unclear, the researchers noted. One potential explanation is that obesity raises the risk of obstructive sleep apnea, which can lead to intermittent hypoxia. This condition may cause oxidative stress, potentially affecting the fetus in ways that could ultimately contribute to SUID in the infant.
Other studies suggested that SUID is unlikely to be directly caused by high maternal BMI itself but is more likely linked to metabolic issues associated with obesity, such as inflammation, insulin resistance, and abnormal lipid metabolism. They also suggested that epigenetic factors might contribute to the connection.
Finally, investigators emphasized the importance of avoiding blame in cases of SUID, as many factors, including uncontrollable genetic influences, contribute to its occurrence. They stressed that the message to parents should not be that a baby’s death was caused by maternal obesity. Instead, the focus should be on using research to uncover underlying mechanisms, such as sleep apnea, that could lead to targeted prevention strategies
