Table 6.
Borderline ovarian tumor risk according to fertility treatment characteristics, excluding the first year of follow-up
| Fertility treatment characteristics | No. of ovarian tumors | No. of women | Adj. HR (95% CI)a |
|---|---|---|---|
| ART exposure | |||
| Non-ART | 17 | 9972 | 1 (Referent) |
| ART | 79 | 30 565 | 1.84 (1.08 to 3.14) |
| Total No. of ART cycles | |||
| 0 | 17 | 9972 | 1 (Referent) |
| 1-2 | 30 | 12 485 | 1.84 (1.00 to 3.37) |
| 3-4 | 33 | 11 587 | 2.04 (1.12 to 3.71) |
| ≥5 | 16 | 6493 | 1.55 (0.78 to 3.09) |
| Total No. of IUI and ART cyclesb | |||
| 0 | 11 | 4574 | 1 (Referent) |
| 1-2 | 25 | 9047 | 1.62 (0.79 to 3.32) |
| 3-4 | 27 | 8688 | 1.69 (0.83 to 3.45) |
| 5-6 | 11 | 4515 | 1.34 (0.58 to 3.12) |
| ≥7 | 15 | 8446 | 1.07 (0.48 to 2.37) |
| Missing | 7 | 5267 | 0.62 (0.24 to 1.61) |
| Response at 1st ART cyclec,d | |||
| Normal response | 38 | 14 943 | 1 (Referent) |
| Poor response | 14 | 4340 | 1.13 (0.61 to 2.09) |
| Missing | 27 | 11 282 | 1.09 (0.66 to 1.79) |
| Clomiphene used | |||
| Never | 28 | 9712 | 1 (Referent) |
| Ever | 13 | 6515 | 0.62 (0.32 to 1.20) |
| Missing | 38 | 14 338 | 0.80 (0.49 to 1.30) |
| Main subfertility diagnosise | |||
| Male factor | 18 | 11 572 | 1 (Referent) |
| Tubal factor | 51 | 12 952 | 2.47 (1.44 to 4.25) |
| Unexplained or other factor | 27 | 16 013 | 1.07 (0.59 to 1.95) |
| Endometriosise,f | |||
| No | 83 | 36 936 | 1 (Referent) |
| Yes | 13 | 3601 | 1.33 (0.74 to 2.40) |
| Paritye | |||
| Nulliparous | 40 | 13 295 | 1 (Referent) |
| Parous | 56 | 26 988 | 0.76 (0.51 to 1.15) |
Analyses include 40 537 women, 30 565 ART-treated women, and 9972 non-ART–treated women. Each variable was analyzed in a separate model. All analyses are adjusted for age at start treatment or first visit to gynecologist, parity, and tubal subfertility. Adj. HR = adjusted hazard ratio; ART = assisted reproductive technology; CI = confidence interval; IUI = intrauterine insemination.
Includes stimulated and nonstimulated IUI cycles. Based on information from medical records if available and on information from questionnaires if no medical record information was available. Women with missing data about IUI cycles and with a tubal cause of subfertility were categorized in the 0 IUI cycles category.
Poor response includes canceled first cycles because of anticipated poor response and less than 4 oocytes; normal response includes 4 or more oocytes collected in first cycle. Too few women with ovarian hyperstimulation syndrome to perform analysis.
Among 30 565 ART-treated women only; 79 borderline ovarian tumor cases.
Additionally adjusted for ART exposure (yes/no), not adjusted for tubal subfertility.
Histologically proven endometriosis, based on information from the Nationwide Network and Registry of Histo- and Cytopathology in the Netherlands (PALGA).