A recent study conducted by scientists at the University of Manchester has shed light on the reasons behind why older mice are more likely to give birth to offspring that have not fully developed in the womb. The research focused on the mechanisms that contribute to this phenomenon, particularly in relation to oxidative stress and placental function.
The study revealed that in older mice, the placentas of male offspring showed increased cell damage due to oxidative stress, while female offspring did not display the same level of damage. Oxidative stress occurs when harmful molecules called free radicals accumulate faster than the body can eliminate them, and it has been linked to various pregnancy complications such as fetal growth restriction and preeclampsia.
Interestingly, the study found that both male and female fetuses from older mice had reduced weight, but the placental alterations were sex-specific. This suggests that there may be distinct mechanisms at play in male and female placentas in response to maternal age.
Further investigations are currently underway to confirm these findings in mice and to explore whether similar sex-differentiation mechanisms exist in human placentas from mothers of advanced maternal age (AMA), which is defined as age 35 and above.
The study, published in the journal Reproduction, also identified changes in placental mitochondria in older mice, with a reduced activity rate but an increased number of mitochondria present. Mitochondria are essential for powering cells but can also generate free radicals. The adaptation of mitochondria in response to oxidative stress may differ between male and female placentas, potentially explaining the sex-specific outcomes observed in the study.
Lead author Dr. Michelles Desforges emphasized the importance of understanding the mechanisms underlying the increased risks associated with advanced maternal age, particularly in relation to fetal growth restriction and stillbirth. The prevalence of pregnancies in women aged 35 and over has significantly increased in recent years, highlighting the need for further research in this area.
Principal investigator Dr. Mark Dilworth highlighted the value of animal studies in exploring sex-specific outcomes and developing potential therapeutic strategies to prevent adverse pregnancy outcomes.
Overall, the study provides valuable insights into the complex interplay between maternal age, placental function, and fetal development. By unraveling these mechanisms, researchers hope to pave the way for improved interventions and care for pregnant women of advanced maternal age.
