TABLE 2.
Characteristics of 1344 pregnancies occurring after July 1, 1973 that ended in spontaneous abortion or live birth.
Livebirth (n=1148) |
SA (n=196) |
Chi Square p value |
Unadjusted OR |
|
---|---|---|---|---|
Pregnancies | N (%) | N (%) | ||
Maternal age at conception (years) | ||||
< 20 | 122 (11%) | 19 (10%) | 0.001 | Ref |
20 – 29 | 801 (70%) | 123 (63%) | 0.99 (0.59-1.66) | |
30 - 34 | 182 (16%) | 34 (17%) | 1.20 (0.65-2.20) | |
≥ 35 | 43 (4%) | 20 (10%) | 2.99 (1.46-6.12) | |
Maternal PBB at conception (ppb) a | ||||
<1 | 625 (54%) | 116 (59%) | 0.21 | Ref |
1 – 2.9 | 221 (19%) | 40 (20%) | 0.98 (0.66-1.44) | |
> 2.9 | 302 (26%) | 40 (20%) | 0.71 (0.49-1.05) | |
PCB exposure (ppb) a | ||||
<5 | 481 (42%) | 85 (43%) | 0.45 | Ref |
5-6.5 | 291 (25%) | 54 (28%) | 1.05 (0.73-1.52) | |
>6.5 | 303 (26%) | 50 (26%) | 0.93 (0.64-1.36) | |
Not measured | 73 (6%) | 7 (4%) | 0.54 (0.24-1.22) | |
Time to pregnancy | ||||
< 12 months | 819 (87%) | 133 (86%) | 0.75 | Ref |
≥ 12 months | 125 (13%) | 22 (14%) | 1.08 (0.67-1.77) | |
Prior spontaneous abortion b | ||||
No | 935 (81%) | 126 (64%) | <0.0001 | Ref |
Yes | 213 (19%) | 70(36%) | 2.44 (1.76-3.39) | |
Number of prior pregnancies b | ||||
0 | 336 (29%) | 38 (19%) | 0.0001 | Ref |
1 | 356 (31%) | 52 (27%) | 1.29 (0.83-2.01) | |
2 | 231 (20%) | 41 (21%) | 1.57 (0.98-2.52) | |
≥ 3 | 225 (20%) | 65 (33%) | 2.55 (1.65-3.94) | |
History of infertility b | ||||
No | 950 (83%) | 144 (73%) | 0.002 | Ref |
Yes | 198 (17%) | 52 (27%) | 1.73 (1.22-2.46) | |
Thyroid problem b | ||||
No | 1046 (86%) | 171 (14%) | 0.03 | Ref |
Yes | 63 (77%) | 19 (23%) | 1.79 (1.05-3.06) | |
Uterine fibroid b | ||||
No | 1126 (98%) | 192 (98%) | 0.84 | Ref |
Yes | 21(2%) | 4 (2%) | 1.12 (0.38-3.29) | |
Endometriosis b | ||||
No | 1099 (96%) | 187 (95%) | 0.84 | Ref |
Yes | 49 (4%) | 9 (5%) | 1.08 (0.52-2.23) | |
PID prior to pregnancy b | ||||
No | 1123 (98%) | 187 (96%) | 0.05 | Ref |
Yes | 21 (2%) | 8 (4%) | 2.29 (1.00-5.24) | |
Maternal smoking during year prior to pregnancy |
||||
No | 905 (79%) | 146 (74%) | 0.15 | Ref |
Yes | 240 (21%) | 50 (26%) | 1.29 (0.91-1.84) | |
First trimester maternal alcohol consumption |
||||
No | 998 (87%) | 165 (86%) | 0.68 | Ref |
Yes | 143 (13%) | 26 (14%) | 1.10 (0.70-1.72) |
Abbreviations: OR, odds ratio, PBB, polybrominated biphenyls; PCB polychlorinated biphenyls; pbb, parts per billion, PID, pelvic inflammatory disease.
PBB and PCB cut-points are based on the limit of detection and the median exposure of spontaneous abortions above the level of detection.
Prior to the index pregnancy