Figure 4.

Associations between air pollutant exposure and clinical pregnancy likelihood at each period: two-pollutant model results. The logistic regression models were adjusted for a range of factors including age, BMI, stimulation protocol, endometrial thickness on the day of hCG administration, total gonadotropin dose, duration and cause of infertility, infertility type, number of retrieved oocytes, number of embryos transferred, stage of embryo transfer, temperature, and dew point. Adjusted pollutants are depicted on the far left, while the main pollutants are on the far right. Odds ratios (ORs) and their corresponding 95% CIs are represented by circles and error bars, with significant associations at the P-value < 0.05 indicated in red. Period 1, 90 days before oocyte retrieval; Period 2, oocyte retrieval to embryo transfer; Period 3, embryo transfer to serum hCG test; Period 4, 90 days before oocyte retrieval to serum hCG test; Gn, gonadotropin; PM_2.5, fine particulate matter (particles ≤ 2.5 µm); PM₁₀, inhalable particulate matter (particles ≤ 10 µm); CO, carbon monoxide; NO₂, nitrogen dioxide; O₃, ozone; SO₂, sulfur dioxide.