Table 1.
Baseline characteristics before and after propensity score matching.
| Before propensity score matching | After propensity score matching | |||||
|---|---|---|---|---|---|---|
| MS-OHSS singleton pregnancies (n = 114) | Non-OHSS singleton pregnancies (n = 3,898) | P value | MS-OHSS singleton pregnancies (n = 114) | Non-OHSS singleton pregnancies(n = 337) | P value | |
| Maternal age (y) | 28.98 ± 3.56 | 30.45 ± 4.14 | <0.01 | 28.98 ± 3.56 | 29.43 ± 3.76 | 0.27 |
| Paternal age (y) | 30.61 ± 5.50 | 31.38 ± 4.78 | 0.09 | 30.61 ± 5.50 | 30.49 ± 4.26 | 0.83 |
| Maternal body mass index(kg/m2) | 22.87 ± 2.79 | 23.60 ± 3.29 | 0.02 | 22.87 ± 2.79 | 22.88 ± 2.98 | 0.96 |
| Duration of infertility (y) | 3.10 ± 2.31 | 3.40 ± 2.63 | 0.22 | 3.10 ± 2.31 | 3.24 ± 2.27 | 0.68 |
| Maternal gravidity (≥1) | 55(48.25) | 2,108(54.08) | 0.22 | 55(48.25) | 170(50.45) | 0.56 |
| Hormone level | ||||||
| Basal serum FSH level (IU/L) | 6.10 ± 1.90 | 6.84 ± 2.05 | <0.01 | 6.10 ± 1.90 | 6.07 ± 1.69 | 0.88 |
| Basal serum E2 level (pmol/L) | 161.81 ± 131.16 | 155.82 ± 98.24 | 0.53 | 161.81 ± 131.16 | 155.94 ± 98.57 | 0.62 |
| Basal serum LH level (IU/L) | 6.86 ± 7.25 | 5.94 ± 5.36 | 0.18 | 6.86 ± 7.25 | 6.27 ± 5.88 | 0.38 |
| Basal serum AMH level (pmol/L) | 37.13 ± 19.95 | 28.33 ± 20.85 | <0.01 | 37.13 ± 19.95 | 36.10 ± 27.68 | 0.67 |
| Serum E2 level on the hCG trigger day (pmol/L) | 10175.38 ± 7282.36 | 9182.46 ± 6463.62 | 0.11 | 10175.38 ± 7282.36 | 10833.96 ± 7090.96 | 0.40 |
| Serum LH level on the hCG trigger day (IU/L) | 1.48 ± 1.10 | 1.55 ± 1.84 | 0.70 | 1.48 ± 1.10 | 1.43 ± 0.90 | 0.60 |
| Basal antral follicle count | 20.68 ± 5.41 | 17.66 ± 6.95 | <0.01 | 20.68 ± 5.41 | 20.63 ± 9.65 | 0.96 |
| Stimulation protocol | 0.04 | 0.69 | ||||
| Early follicular long-term protocol (%) | 87(76.32) | 2,637(67.65) | 87(76.32) | 242(71.81) | ||
| Luteal medium long-term protocol (%) | 12(10.53) | 759(19.47) | 12(10.53) | 48(14.24) | ||
| Antagonist protocol (%) | 8(7.02) | 353(9.06) | 8(7.02) | 29(8.61) | ||
| Other protocol (%) | 7(6.14) | 149(3.82) | 7(6.14) | 18(5.34) | ||
| Infertility diagnosisa | 0.91 | 0.96 | ||||
| Male factor (%) | 16(14.04) | 599(15.37) | 16(14.04) | 50(14.84) | ||
| Female factor (%) | 62(54.39) | 2,176(55.82) | 62(54.39) | 190(56.38) | ||
| Couple factor (%) | 27(23.68) | 822(21.09) | 27(23.68) | 73(21.66) | ||
| Unexplained (%) | 9(7.89) | 301(7.72) | 9(7.89) | 24(7.12) | ||
| Treatment type | 0.65 | 0.94 | ||||
| IVF (%) | 87(76.32) | 2,901(74.42) | 87(76.32) | 256(75.96) | ||
| ICSI (%) | 27(23.68) | 997(25.58) | 27(23.68) | 81(24.04) | ||
| Day of embryo transferred | <0.01 | 0.89 | ||||
| Day 3 (%) | 54(47.37) | 2,547(65.34) | 54(47.37) | 157(46.59) | ||
| Day 5 or 6 (%) | 60(52.63) | 1,351(34.66) | 60(52.63) | 180(53.41) | ||
| No. of embryo transferred | <0.01 | 0.87 | ||||
| 1 (%) | 66(57.89) | 1,646(42.23) | 66(57.89) | 198(58.75) | ||
| 2 (%) | 48(42.11) | 2,252(57.77) | 48(42.11) | 139(41.25) | ||
| No. of oocytes retrieved | 16.11 ± 5.22 | 12.64 ± 5.3 | <0.01 | 16.11 ± 5.22 | 16.18 ± 5.71 | 0.91 |
| Endometrial thickness at the day of embryo transfer | 11.81 ± 5.29 | 11.36 ± 2.22 | 0.37 | 11.81 ± 5.29 | 11.5 ± 2.13 | 0.55 |
Data are presented as mean ± standard deviation or n (%). The variables in the propensity score matching included maternal age, maternal body mass index, basal serum FSH level, basal serum AMH level, type of stimulation protocol, basal antral follicle count, number of oocytes retrieved, day of embryo development for embryo transfer, number of embryo transferred. MS-OHSS, moderate-to-severe ovarian hyperstimulation syndrome; FSH, follicle-stimulating hormone; LH, luteinizing hormone; E2, estradiol; AMH, anti-Müllerian hormone; hCG, human chorionic gonadotropin; IVF, In vitro fertilization; ICSI, intracytoplasmic sperm injection.