Table 4 Comparison of early miscarriage and late miscarriage in ART clinical pregnancies
Variables | Early miscarriage | Late miscarriage | ||||||
|---|---|---|---|---|---|---|---|---|
Nc (%) | n (%) | HR (95%CI)a | P a | Nd (%) | n (%) | HR (95%CI)a | P a | |
Maternal age | ||||||||
  < 30 | 2556(47.0) | 180(39.5) | 1.00 |  | 2376(47.7) | 94(49.7) | 1.00 |  |
 30–35 | 2361(43.4) | 188(41.2) | 1.14(0.93–1.40) | 0.215 | 2173(43.6) | 80(42.3) | 0.93(0.69–1.25) | 0.630 |
 36–40 | 472(8.7) | 69(15.1) | 2.14(1.62–2.83) | <0.001 * | 403(8.1) | 15(7.9) | 0.94(0.54–1.62) | 0.823 |
  > 40 | 53(1.0) | 19(4.2) | 6.04(3.76–9.69) | <0.001 * | 34(0.7) | 0(0.0) | 0 | 0.992 |
Maternal BMI | ||||||||
  < 18.5 | 509(9.4) | 32(7.0) | 0.82(0.57–1.18) | 0.282 | 477(9.7) | 15(8.1) | 0.82(0.52–1.51) | 0.647 |
 18.5–25 | 4009(74.3) | 335(73.3) | 1.00 |  | 3674(74.4) | 130(70.3) | 1.00 |  |
 25–28 | 641(11.9) | 65(14.2) | 1.19(0.91–1.55) | 0.205 | 576(11.7) | 24(13.0) | 1.20(0.78–1.86) | 0.407 |
 ≥28 | 235(4.4) | 25(5.5) | 1.35(0.90–2.03) | 0.145 | 210(4.3) | 16(8.6) | 2.09(1.22–3.57) | 0.007 * |
Paternal BMI | ||||||||
  < 18.5 | 103(1.9) | 8(1.8) | 1.07(0.53–2.16) | 0.859 | 95(1.9) | 1(0.5) | 0.00(0.00 − +∞) | 0.992 |
 18.5–25 | 3309(61.7) | 266(58.6) | 1.00 |  | 3043(62.0) | 120(64.9) | 1.00 |  |
 25–28 | 1344(25.1) | 129(28.4) | 1.17(0.95–1.45) | 0.137 | 1215(24.8) | 50(27.0) | 1.06(0.76–1.48) | 0.728 |
  ≥ 28 | 603(11.3) | 51(11.2) | 1.08(0.80–1.46) | 0.616 | 552(11.3) | 14(7.6) | 0.64(0.37–1.12) | 0.118 |
Infertility type | ||||||||
 Primary | 2781(53.0) | 227(51.1) | 1.00 |  | 2554(53.2) | 92(51.7) | 1.00 |  |
 Secondary | 2466(47.0) | 217(48.9) | 0.94(0.78–1.14) | 0.544 | 2249(46.8) | 86(48.3) | 1.10(0.81–1.49) | 0.538 |
COH protocolb | ||||||||
 GnRH-a long protocol | 3406(63.1) | 243(53.4) | 1.00 |  | 3163(64.0) | 125(67.9) | 1.00 |  |
 GnRH-a short protocol | 1573(29.2) | 132(29.0) | 1.00(0.80–1.26) | 0.974 | 1441(29.2) | 48(26.1) | 0.85(0.60–1.21) | 0.370 |
 GnRH antagonist protocol | 95(1.8) | 29(6.4) | 4.11(2.78–6.08) | <0.001 * | 66(1.3) | 5(2.7) | 1.95(0.80–4.78) | 0.144 |
 Minimal stimulation protocol | 186(3.4) | 40(8.8) | 2.39(1.67–3.43) | <0.001 * | 146(3.0) | 1(0.5) | 0.18(0.02–1.29) | 0.088 |
 GnRH-a rolonged protocol | 123(2.3) | 8(1.8) | 0.90(0.44–1.82) | 0.765 | 115(2.3) | 3(1.6) | 0.67(0.21–2.11) | 0.492 |
 Other protocol | 13(0.2) | 3(0.7) | 3.27(1.04–10.23) | 0.042 * | 10(0.2) | 2(1.1) | 5.52(1.36–22.40) | 0.017 * |
The total Gn dose | ||||||||
  < 1808.01 | 3181(59.0) | 252(55.4) | 1.00 |  | 2929(59.4) | 104(56.2) | 1.00 |  |
  ≥ 1808.01 | 2208(41.0) | 203(44.6) | 1.08(0.89–1.30) | 0.440 | 2005(40.6) | 81(43.8) | 1.15(0.86–1.54) | 0.355 |
Fertilization methods | ||||||||
 IVF | 4543(83.9) | 386(84.6) | 1.00 |  | 4157(83.8) | 162(86.6) | 1.00 |  |
 ICSI | 875(16.1) | 70(15.4) | 0.93(0.72–1.20) | 0.562 | 805(16.2) | 25(13.4) | 0.81(0.53–1.23) | 0.320 |
Cycle type | ||||||||
 Fresh | 2675(51.9) | 161(39.1) | 1.00 |  | 2514(53.0) | 106(60.6) | 1.00 |  |
 Frozen | 2477(48.1) | 251(60.9) | 1.67(1.37–2.04) | <0.001 * | 2226(47.0) | 69(39.4) | 0.73(0.54–0.99) | 0.045 * |
No. of embryos transferred | ||||||||
 1 | 474(8.7) | 64(14.0) | 1.00 |  | 410(8.2) | 16(8.4) | 1.00 |  |
 2 | 4324(79.6) | 330(72.1) | 0.61(0.47–0.80) | <0.001 * | 3994(80.2) | 157(82.6) | 0.99(0.59–1.65) | 0.961 |
 3 | 637(11.7) | 64(14.0) | 0.63(0.44–0.89) | 0.010 * | 573(11.5) | 17(8.9) | 0.75(0.38–1.51) | 0.425 |
Cleavage-stage embryo or blastocystb | ||||||||
 Cleavage-stage embryo | 3860(73.3) | 305(68.2) | 1.00 |  | 3555(73.8) | 135(73.8) | 1.00 |  |
 Blastocyst | 1405(26.7) | 142(31.8) | 1.15(1.04–1.27) | 0.006 * | 1263(26.2) | 48(26.2) | 1.00(0.85–1.18) | 0.994 |
Serum hCG levels 14Â days after transfer | ||||||||
  < 695.30 | 2187(52.2) | 248(82.7) | 1.00 |  | 1939(49.8) | 79(59.8) | 1.00 |  |
  ≥ 695.30 | 2006(47.8) | 52(17.3) | 0.22(0.16–0.30) | <0.001 * | 1954(50.2) | 53(40.2) | 0.68(0.48–0.96) | 0.030 * |