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Table 1 Target populations and data collection in an international study of fertility.

From: Fertility in four regions spanning large contrasts in serum levels of widespread persistent organochlorines: a cross-sectional study

  Warsawa Kharkiva Greenlanda Swedenb Total
Eligible female target population, n 690 2478 665 1439 5272
Interviewed, n 472 640 598 559 2269
Participation rate, % 68 26 90 39 43
Contraceptive failures, % 19 48 6 21 26
Provided valid TTPc, n 376 307 520 519 1722
   Stated TTP, n 369 301 455 513 1638
   Calculated TTP, n 7 4 57 0 68
   TTP in cycles d , n 0 2 8 6 16
Questionnaire, mene, n 472 576 637 195 1880
Eligible men addressed for the semen study 690 640 256 2783 4369
Collected semen samplesf 198 208 201 191 798
Participation rate, % 29 33 79 7 18
   Sperm motility, manual counting 190 208 200 188 786
   Sperm motility, computer assisted 165 0 198 179 542
   Sperm morphology 197 206 200 184 787
  1. a) Consecutive pregnant woman and their spouses.
  2. b) Retrospective studies of past pregnancies.
  3. c) TTP were considered not valid if the woman was using birth control when becoming pregnant (47 Inuits, 47 Warsaw women, and 297 Kharkiv women), did not provide information on whether she was using birth control (n = 26), was multipara and had not menstruated since her previous pregnancy (n = 16), or had not provided information on whether she had menstruated since her previous pregnancy (n = 5).
  4. d) Possibly censored measure.
  5. e) The total number of individuals with questionnaire information on males. Data were obtained by interviewing the spouse if no male interview was performed.
  6. f) All collected semen samples were analysed for sperm concentration and volume.