Table 3.
Observed and expected cases of adverse birth outcomes among infants conceived with IVF in mothers with normal BMI.
| ABOs | Group | IVF | IVF-Fresh | IVF-Frozen | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total no | No. of events | SRR* (95%CI) | Total no | No. of events | SRR* (95%CI) | Total no | No. of events | SRR* (95%CI) | |||||
| Observed | Expected# | Observed | Expected# | Observed | Expected# | ||||||||
| PTB | IVF Total | 9480 | 625 | 543.2 | 1.15(1.06,1.24) | 694 | 37 | 39.8 | 0.93(0.67,1.28) | 8786 | 588 | 503.4 | 1.17(1.08,1.27) |
| Excluding infertility factors affecting ABOs $ | 3787 | 229 | 217.0 | 1.06(0.93,1.20) | 336 | 16 | 19.3 | 0.83(0.51,1.36) | 3451 | 213 | 197.7 | 1.08(0.94,1.23) | |
| Unexplained infertility cause | 111 | 8 | 6.4 | 1.26(0.63,2.52) | – | – | – | – | 99 | 8 | 5.7 | 1.41(0.71,2.82) | |
| Tubal factor infertility | 3333 | 199 | 191.0 | 1.04(0.91,1.20) | 286 | 13 | 16.4 | 0.79(0.46,1.37) | 3047 | 186 | 174.6 | 1.07(0.92,1.23) | |
| LBW | IVF Total | 9480 | 392 | 348.9 | 1.12(1.02,1.24) | 694 | 25 | 25.5 | 0.98(0.66,1.45) | 8786 | 367 | 323.3 | 1.14(1.02,1.26) |
| Excluding infertility factors affecting ABOs $ | 3787 | 133 | 139.4 | 0.95(0.81,1.13) | 336 | 12 | 12.4 | 0.97(0.55,1.71) | 3451 | 121 | 127.0 | 0.95(0.80,1.14) | |
| Unexplained infertility cause | 111 | 3 | 4.1 | 0.73(0.24,2.28) | – | – | – | – | 99 | 3 | 3.6 | 0.82(0.27,2.55) | |
| Tubal factor infertility | 3333 | 115 | 122.7 | 0.94(0.78,1.13) | 286 | 10 | 10.5 | 0.95(0.51,1.77) | 3047 | 105 | 112.1 | 0.94(0.77,1.13) | |
| Macrosomia | IVF total | 9480 | 821 | 610.5 | 1.34(1.26,1.44) | 694 | 56 | 44.7 | 1.25(0.96,1.63) | 8786 | 765 | 565.8 | 1.35(1.26,1.45) |
| Excluding infertility factors affecting ABOs $ | 3787 | 308 | 243.9 | 1.26(1.13,1.41) | 336 | 23 | 21.6 | 1.06(0.71,1.60) | 3451 | 285 | 222.2 | 1.28(1.14,1.44) | |
| Unexplained Infertility cause | 111 | 10 | 7.1 | 1.40(0.75,2.60) | 12 | 1 | 0.8 | 1.29(0.18,9.19) | 99 | 9 | 6.4 | 1.41(0.73,2.71) | |
| Tubal factor infertility | 3333 | 271 | 214.6 | 1.26(1.12,1.42) | 286 | 22 | 18.4 | 1.19(0.79,1.81) | 3047 | 249 | 196.2 | 1.27(1.12,1.44) | |
| SGA | IVF total | 9480 | 472 | 486.3 | 0.97(0.89,1.06) | 694 | 28 | 35.6 | 0.79(0.54,1.14) | 8786 | 444 | 450.7 | 0.99(0.90,1.08) |
| Excluding infertility factors affecting ABOs $ | 3787 | 174 | 194.3 | 0.90(0.77,1.04) | 336 | 16 | 17.2 | 0.93(0.57,1.52) | 3451 | 158 | 177.0 | 0.89(0.76,1.04) | |
| Unexplained infertility cause | 111 | 7 | 5.7 | 1.23(0.59,2.58) | 12 | 1 | 0.6 | 1.62(0.23,11.53) | 99 | 6 | 5.1 | 1.18(0.53,2.63) | |
| Tubal factor infertility | 3333 | 149 | 171.0 | 0.87(0.74,1.02) | 286 | 12 | 14.7 | 0.82(0.46,1.44) | 3047 | 137 | 156.3 | 0.88(0.74,1.04) | |
| LGA | IVF total | 9480 | 1689 | 1342.4 | 1.26(1.20,1.32) | 694 | 119 | 98.3 | 1.21(1.01,1.45) | 8786 | 1570 | 1244.1 | 1.26(1.20,1.33) |
| Excluding infertility factors affecting ABOs $ | 3787 | 662 | 536.2 | 1.23(1.14,1.33) | 336 | 53 | 47.6 | 1.11(0.85,1.46) | 3451 | 609 | 488.7 | 1.25(1.15,1.35) | |
| Unexplained infertility cause | 111 | 22 | 15.7 | 1.40(0.92,2.13) | 12 | 1 | 1.7 | 0.59(0.08,4.18) | 99 | 21 | 14.0 | 1.50(0.98,2.30) | |
| Tubal factor infertility | 3333 | 589 | 472.0 | 1.25(1.15,1.35) | 286 | 47 | 40.5 | 1.16(0.87,1.54) | 3047 | 542 | 431.5 | 1.26(1.15,1.37) | |
#The number of expected cases was calculated by applying the rates of PTB, LBW, macrosomia, SGA and LGA from the birth registry data to the population of infants conceived with assisted reproductive technology. The values were adjusted to account for differences in the distributions of year of birth, maternal age, infant sex and parity between the two populations.
*SRR standardized risk ratio.
$Infertility factors affecting ABOs meant infertility factors that influenced the birth outcomes, including semen abnormalities, endometriosis, polycystic ovary syndrome and uterine factor infertility.
Statistical differences are shown in bold.