Table 1.
Baseline characteristics of the study subjects (%).
| Variables | Outbreak period (n = 599) | Control period (n = 892) | χ2 value | P-value |
|---|---|---|---|---|
| Women's age (year), n (%) | ||||
| <30 | 170 (28.38) | 294 (32.96) | ||
| 30–34.99 | 303 (50.58) | 411 (46.08) | 3.936 | 0.140 |
| ≥35 | 126 (20.04) | 187 (20.96) | ||
| Education level, n (%) | ||||
| Junior high school and below | 130 (21.70) | 199 (22.31) | 0.706 | 0.872 |
| High school/secondary school | 112 (18.70) | 170 (19.06) | ||
| College | 154 (25.71) | 239 (26.79) | ||
| University and above | 203 (33.89) | 284 (31.84) | ||
| Occupation, n (%) | ||||
| Professional and technical | 114 (19.03) | 140 (15.70) | ||
| personnel | ||||
| Administrative staff | 65 (10.85) | 125 (14.01) | ||
| Workers/service staff | 89 (14.86) | 154 (17.26) | 11.067 | 0.026 |
| Other | 116 (19.37) | 200 (22.42) | ||
| Unemployed | 215 (35.89) | 273 (30.61) | ||
| Residence, n (%) | ||||
| City | 163 (27.21) | 241 (27.02) | ||
| Town | 107 (17.86) | 133 (14.91) | 2.571 | 0.277 |
| Rural | 329 (54.92) | 518 (58.07) | ||
| Family monthly income level (yuan*), n (%) | ||||
| <2,500 | 103 (17.20) | 139 (15.58) | 6.448 | 0.092 |
| 2,055–4,999 | 226 (37.73) | 324 (36.32) | ||
| 5,000–9,999 | 173 (28.88) | 238 (26.68) | ||
| ≥10,000 | 97 (16.19) | 191 (21.41) | ||
| Number of family children | ||||
| 0 | 547 (91.32) | 792 (88.79) | 2.505 | 0.114 |
| ≥1 | 52 (8.68) | 100 (11.21) | ||
| Phases of ART treatment | ||||
| Before IVF treatment | 164 (27.38) | 364 (40.81) | 195.102 | <0.001 |
| First cycle of IVF | 100 (16.69) | 338 (37.89) | ||
| Second cycle of IVF | 222 (37.06) | 127 (14.24) | ||
| Third and later cycle of IVF | 113 (18.86) | 63 (7.06) | ||
IVF, in vitro fertilization.
*
Exchange rate of USD to RMB 1–7.