A recent study from Lund University in Sweden has found a link between specific defects in sperm and the risk of pregnancy complications as well as negative impacts on the health of the baby. The research shows that a high proportion of DNA strand breaks in a father’s sperm is associated with a doubled risk of preeclampsia in women who have become pregnant through IVF, as well as an increased likelihood of premature birth. This finding sheds light on the potential reasons behind the increased risks often seen in pregnancies resulting from assisted reproduction techniques.
Infertility is a growing concern, leading to an increase in the number of in vitro fertilisation procedures being performed. While it is known that women who become pregnant through assisted reproduction have a higher risk of preeclampsia, repeated miscarriages, premature birth, and lower birth weight babies, the underlying reasons have not been fully understood. This study aimed to investigate the impact of DNA fragmentation in sperm on pregnancy outcomes and the health of the baby, providing new insights into male fertility and its effects on assisted reproduction techniques.
The research revealed that around 20-30% of babies born through IVF have fathers with damaged DNA in their sperm, indicated by elevated levels of DNA fragmentation. The DNA fragmentation index (DFI) is a measure of strand breaks in the DNA and offers valuable information about male fertility. Men with high DFI levels may still be fertile, but their chances of fertilisation are lower, with natural conception becoming close to impossible when the DFI exceeds 30%. This highlights the importance of assessing DNA damage in sperm samples before assisted reproduction procedures to improve outcomes.
While current IVF techniques have allowed men with high DFI levels to become fathers, there has been limited understanding of the impact of DNA fragmentation on pregnancy and the baby’s health until now. The lack of inclusion of DFI in standard fertility clinic measurements in Sweden has hindered research in this area. The study required a large population and access to national medical registries to investigate the association between sperm DNA damage and the risk of preeclampsia, shedding light on the importance of considering this factor in fertility assessments.
The findings from the study showed that a DFI of over 20% doubled the risk of preeclampsia in women who underwent IVF, as well as increasing the likelihood of premature birth. Couples undergoing IVF with a DFI below 20% had a risk of preeclampsia comparable to naturally conceived pregnancies. The study did not find an association between DFI and preeclampsia in couples undergoing ICSI. This highlights the potential of DFI analysis to provide insights into infertility causes and guide the choice of assisted fertilisation methods to improve outcomes.
The researchers suggest that DFI analysis should be introduced as a standard procedure at all fertility clinics in Sweden to provide couples with answers about their infertility and potentially identify high-risk pregnancies. High DNA fragmentation in sperm is linked to the overall health of the father and is potentially treatable, with factors such as oxidative stress, age, smoking, obesity, and infections playing a role in DNA damage. The next steps involve identifying men who respond best to treatments to prevent and treat sperm DNA damage, with the aim of reducing the risk of pregnancy complications and improving outcomes for assisted reproduction procedures.