Ozone Exposure and Gestational Diabetes in Twin Pregnancies: Exploring Critical Windows and Synergistic Risks

Area of Science:

• Environmental Health
• Reproductive Health
• Obstetrics

Background:

• Gestational diabetes mellitus (GDM) is a significant complication in pregnancy.
• The impact of environmental factors like ozone (O₃) on GDM risk, particularly in twin pregnancies, is not well understood.
• Twin pregnancies have unique physiological characteristics that may alter susceptibility to environmental exposures.

Purpose of the Study:

• To investigate the association between ozone (O₃) exposure and the risk of developing gestational diabetes mellitus (GDM) in twin pregnancies.
• To identify critical exposure windows for O₃ and GDM risk in this population.
• To explore potential synergistic effects between O₃ exposure and other maternal risk factors for GDM.

Main Methods:

• A prospective cohort study involving 428 twin pregnancies.
• Application of Cox proportional hazard models and distributed lag non-linear models (DLNMs) to assess O₃ exposure and GDM risk.
• Analysis of multiplicative and additive interactions to evaluate synergistic effects with maternal factors.

Main Results:

• A 10 μg/m³ increase in average O₃ exposure during the 12 weeks preceding pregnancy was linked to a 26% higher GDM risk.
• Critical exposure windows were identified from the 3rd week before gestation to the 2nd gestational week, and from the 17th to 19th gestational week.
• Synergistic effects were observed between high periconceptional O₃ exposure and advanced maternal age or a history of adverse pregnancy outcomes (preterm birth, abortion, stillbirth).

Conclusions:

• Periconceptional ozone exposure is a significant risk factor for GDM in women with twin pregnancies.
• Ozone exposure interacts synergistically with established maternal risk factors, potentially increasing GDM incidence.
• These findings highlight the importance of environmental monitoring and targeted interventions for pregnant women, especially those with twin gestations and other risk factors.