A study found that high levels of sperm DNA fragmentation were associated with an increased risk of preeclampsia in pregnancies conceived through in vitro fertilization. The research also linked a high DNA fragmentation index to a greater risk of preterm birth across all assisted reproductive technology pregnancies examined, but no significant differences were noted in other outcomes.
In the study, published in Fertility and Sterility, investigators analyzed the data from 1,594 infertile couples undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment and their 1,660 resulting children.
The prospective cohort study utilized the Swedish Medical Birth Register for outcome data. Sperm samples were analyzed using the Sperm Chromatin Structure Assay to determine DNA fragmentation index (DFI) levels.
The investigators found that men with a DFI ≥ 20% had a 2.2 times higher risk (95% confidence interval [CI] = 1.1–4.4) of their partners developing preeclampsia in IVF pregnancies compared with those with DFI < 20%. This association was not observed in ICSI pregnancies.
A dose-response effect was noted, with increased preeclampsia risk starting at DFI levels > 10% in IVF pregnancies. The prevalence of preeclampsia increased from 3.1% in the reference group (DFI < 10%) to over 10% among those with a DFI level ≥ 30%.
The risk of preterm birth was 1.4 times higher (95% CI = 1.0–2.0) across all assisted reproductive technology (ART) pregnancies when DFI was ≥ 20%. However, similar risk estimates for preterm birth, without reaching statistical significance, were seen in both the IVF and ICSI groups separately.
No significant associations were found between high DFI and other examined outcomes, including low birth weight, small for gestational age, or low Apgar scores. The study reported no clinically significant differences in birth weight, gestational age, or other baseline characteristics between the high- and low-DFI groups.
The investigators noted that 4% of the included pregnancies were multiple pregnancies, and 11% of embryo transfers were double embryo transfers. The proportion of ICSI cycles was higher in the group with DFI ≥ 20% compared with the group with DFI < 20%.
Study limitations included the nonrandomized nature of IVF vs ICSI treatment assignment and lack of information on women's previous medical histories. The large cohort size (1,594 couples) and low dropout rate were noted as strengths.
The findings highlighted potential differences in the impact of sperm DNA fragmentation between IVF and ICSI procedures. The study suggested that different DFI thresholds may exist for an increased risk of preeclampsia and preterm birth, with no significant effects seen for other outcomes.
The researchers emphasized the need for further research to confirm these findings and investigate potential mechanisms linking sperm DNA fragmentation to pregnancy complications.
Conflict of interest disclosures can be found in the study.