TOPLINE:

The use of assisted reproductive technologies (ARTs) was associated with a modest increase in the risk for cardiovascular disease (CVD), without a clear overall dose-response relationship. Programmed frozen cycles showed a stronger association with CVD and a clear dose-response relationship as their number increased.

METHODOLOGY:

• Researchers analysed Norwegian registry data on women born between 1965 and 2000 who were alive and living in Norway in 2009 to see whether the number of ART cycles was linked to later hypertension and CVD.
• They included over 1.61 million women and identified ART cycles from pharmacy prescription records between 2004 and 2020, with cycles classified as either fresh (70.57%) or frozen (29.43%).
• Among women who underwent ARTs, 28.70% had one cycle, 20.86% had two cycles, 15.92% had three cycles, and 34.52% had four or more cycles by the end of follow-up.
• Researchers compared the occurrence of chronic hypertension and CVD using two reference groups: women unexposed to ARTs and ART users who underwent one cycle.
• Total follow-up exceeded 15 million person-years in the analysis comparing ART users with non-users and exceeded 175,000 person-years in the analysis restricted to ART users comparing additional cycles with one cycle.

TAKEAWAY:

• Each additional ART cycle was associated with a small rise in the risk for CVD compared with no ART (adjusted hazard ratio [aHR], 1.07; 95% CI, 1.04-1.10), with no clear dose-response relationship; no such association with chronic hypertension was reported.
• The excess risk for CVD was mainly driven by deep vein thrombosis (aHR, 1.18; 95% CI, 1.11-1.25) and pulmonary embolism (aHR, 1.17; 95% CI, 1.06-1.29).
• Among ART users, each additional cycle was associated with a 7% increased risk for CVD (aHR, 1.07; 95% CI, 1.02-1.13). Compared with exposure to one cycle, exposure to four or more cycles showed a larger but imprecise increase in the risk (aHR, 1.34; 95% CI, 0.99-1.81).
• Each additional programmed frozen ART cycle was linked to an increased risk for CVD (aHR, 1.35; 95% CI, 1.18-1.55), with a clear dose-response relationship as aHRs ranged from 2.95 to 5.64 as the number of cycles increased.

IN PRACTICE:

"Our findings support the notion that women who have undergone ART might benefit from monitoring of their cardiovascular health," the authors of the study wrote.

SOURCE:

This study was led by Huong Thu Nguyen, PhD, Norwegian Institute of Public Health, Oslo, Norway. It was published online on December 03, 2025, in the European Journal of Preventive Cardiology.

LIMITATIONS:

Exposure may have been misclassified because natural frozen cycles and private clinic procedures were not captured. Certain confounding factors were unaccounted for. The sample size limited analyses by subtypes of CVD.

DISCLOSURES:

This study received funding through a grant from the European Research Council under the European Union's Horizon 2020 research and innovation programme. Additional support came from the Research Council of Norway, Centre of Excellence funding scheme, Central Norway Regional Health Authorities, and British Heart Foundation. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.