Recent research from Swedish and Danish scientists has revealed a concerning link between sperm DNA damage and an increased risk of pregnancy complications, particularly in women who conceive through in vitro fertilisation (IVF). The study indicates that a high DNA fragmentation index (DFI) in spermatozoa is associated with a doubled risk of pre-eclampsia and an increased likelihood of premature birth.
While it is already known that assisted reproductive technologies like IVF and intracytoplasmic sperm injection (ICSI) carry a higher risk of pre-eclampsia, miscarriage, and preterm delivery, the underlying causes have remained unclear. Dr. Amelie Stenqvist from Lund University explained that men with seemingly normal sperm—based on traditional assessments of concentration, motility, and morphology—can still face fertility issues due to undetected DNA damage.
The study, conducted at Lund University and the Reproductive Medicine Centre in Malmö, analyzed 1,660 children conceived via IVF and ICSI between 2007 and 2018. One significant finding was that fathers of 20–30% of IVF-conceived babies had elevated DNA fragmentation levels in their sperm. This damage, measured by the DFI, correlates with lower fertility and could explain some of the challenges these couples face in conception. If the DFI exceeds 30%, the likelihood of natural conception is nearly nonexistent.
In the IVF group, sperm with a DFI above 20% led to a 10.5% incidence of pre-eclampsia, a condition characterized by high blood pressure and damage to organs like the liver and kidneys during pregnancy. This risk was significantly higher compared to the 4.8% incidence of pre-eclampsia observed in IVF pregnancies with a DFI below 20%. Interestingly, for couples using ICSI, there was no link between sperm DNA fragmentation and pre-eclampsia.
Professor Aleksander Giwercman, who led the study, advocates for the inclusion of DFI testing as a standard procedure in fertility clinics. “Introducing DFI analysis in all fertility clinics could provide valuable insights into male fertility and help explain why some couples struggle to conceive,” Giwercman said. “Furthermore, it could identify high-risk pregnancies and guide treatment strategies.”
Sperm DNA fragmentation, which can still result in successful fertilization, is primarily caused by oxidative stress—an imbalance between harmful molecules and the antioxidants that protect cells. Other contributing factors include aging, smoking, obesity, and infections, all of which can damage sperm DNA.
The study emphasizes the importance of addressing sperm health in the context of assisted reproduction, with future research aimed at determining which men may benefit from treatments to reduce DNA fragmentation and prevent pregnancy complications.
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