Table 4.
Maternal characteristics and pregnancy complications of pregnancies carried to delivery after transferring embryos with or without blastomere loss
| Intact embryo group (n = 2962) | Blastomere loss group (n = 407) | p value | |
|---|---|---|---|
| No. (%) | No. (%) | ||
| Maternal socio-demographic characteristics | |||
| Pre-gestational BMI, mean (SD), kg/m2 | 21.79 ± 2.92 | 21.63 ± 2.66 | 0.265 |
| Education attainment | |||
| Primary school or lower | 104 (3.5) | 19 (4.7) | 0.487 |
| Middle or high school | 1524 (51.5) | 204 (50.1) | |
| Collage or above | 1334 (45.0) | 184 (45.2) | |
| Maternal smoking during pregnancy | 5 (0.2) | 1 (0.3) | 0.538 |
| Paternal smoking during pregnancy | 379 (12.8) | 71 (17.4) | 0.010 |
| History of reproduction | |||
| Parity | 164 (5.5) | 32 (7.9) | |
| 1 | 155 (5.2) | 30 (7.4) | 0.109 |
| ≥ 2 | 9 (0.3) | 2 (0.5) | |
| Number of previous abortion | |||
| 0 | 1597 (53.9) | 184 (45.2) | 0.004 |
| 1–2 | 1095 (37.0) | 180 (44.2) | |
| ≥ 3 | 270 (9.1) | 43 (10.6) | |
| Previous ectopic pregnancy | |||
| No | 2935 (99.1) | 403 (99.0) | 0.784 |
| Yes | 27 (0.9) | 4 (1.0) | |
| Duration of infertility, year | |||
| ≤ 2 | 863 (29.1) | 125 (30.7) | 0.795 |
| 3–4 | 1008 (34.0) | 137 (33.7) | |
| ≥ 5 | 1091 (36.8) | 145 (35.6) | |
| Primary infertility | |||
| No | 1555 (52.5) | 179 (44.0) | 0.001 |
| Yes | 1407 (47.5) | 228 (56.0) | |
| Causes of infertility | |||
| Tubal infertility | 1625 (54.9) | 222 (54.6) | 0.633 |
| Anovulatory | 70 (2.4) | 12 (3.0) | |
| Endometriosis | 60 (2.0) | 8 (2.0) | |
| Male-factor infertility | 549 (18.5) | 78 (19.2) | |
| Unexplained infertility | 87 (2.9) | 6 (1.5) | |
| Combineda | 571 (19.3) | 81 (19.9) | |
| Type of embryo cryopreservation | |||
| Slowing freezing | 1037 (35.0) | 318 (78.1) | < 0.001 |
| Vitrification | 1925 (65.0) | 89 (21.9) | |
| Type of FET cycle | |||
| Natural | 1559 (52.6) | 216 (53.1) | 0.435 |
| HRT | 858 (29.0) | 126 (31.0) | |
| OS | 545 (18.4) | 65 (16.0) | |
| Pregnancy complications | |||
| Gestational diabetes mellitus | |||
| No | 2773 (93.6) | 383 (94.1) | 0.707 |
| Yes | 189 (6.4) | 24 (5.9) | |
| Hypertensive disorder | |||
| No | 2525 (85.3) | 349 (85.8) | 0.994 |
| Gestational hypertension | 201 (6.8) | 27 (6.6) | |
| Mild pre-eclampsia | 166 (5.6) | 22 (5.4) | |
| Wild pre-eclampsia | 70 (2.4) | 9 (2.2) | |
| Intrahepatic cholestasis of pregnancy | |||
| No | 2856 (96.4) | 388 (95.3) | 0.276 |
| Yes | 106 (3.6) | 19 (4.7) | |
| Amniotic fluid abnormality | |||
| No | 2842 (96.0) | 388 (95.3) | 0.835 |
| Hydramnios | 46 (1.6) | 7 (1.7) | |
| Oligohydramnios | 74 (2.5) | 12 (3.0) | |
| Preterm delivery b | |||
| No | 2323 (78.4) | 326 (80.1) | 0.741 |
| Preterm | 546 (18.4) | 69 (17.0) | |
| Very preterm | 93 (3.1) | 12 (3.0) | |
| Mode of delivery | |||
| Vaginal | 456 (15.4) | 41 (10.1) | 0.005 |
| Cesarean section | 2506 (84.6) | 366 (89.9) | |
FET frozen-thawed embryo transfer, BMI body mass index, HRT hormone replacement therapy, OS ovarian stimulation, NA not accessible
aCombined was defined as two or more infertile causes mentioned above
bPreterm was defined as delivery prior to 37 gestational weeks, and very preterm was defined as delivery between 28 and 32 gestational weeks