Table 1. Baseline and cycle characteristics of the overall population (n=444) and each group (control vs. PPO group). The overall data are shown in the first column, while columns 2 and 3 contain the data that refer to each group and their comparison. The numeric variables are shown as mean±standard deviation. A p value refers to the comparison using an ANOVA test. MWMann-Whitney test due to a negative homogeneity of variances test; non-parametric data are shown by median± interquartile range. The categorical variables are shown as proportion. A p value refers to the comparison using the Chi-square test. *p=0.05 was considered statistically significant. BMI = body mass index; AMH = antimullerian hormone; PGT-A = pre-implantational genetic testing for aneuploidies. PPO = partial premature ovulation. FSH = follicle stimulating hormone. hMG = human menopausal gonadotropin. hCG = human chorionic gonadotropin. GnRh-a = gonadotropin releasing hormone agonist. E2 = estradiol. P4= progesterone. IQR = interquartile range.
OVERALL N=444 PPO GROUP N=111 CONTROL GROUP N=333 p value
Age 37.8±3.8 37.7±3.3 37.9±4.0 0.684
BMI 23.9±4.1 23.9±4.0 23.9±4.1 0.928
AMH 2.2±2.1 1.9±2.7 2.3±1.9 0.190
Semen origin
Partner semen
Donated semen
348/404 (86.1%)
56/404 (13.9%)
64/71 (90.1%)
7/71 (9.9%)
284 (85.3%)
49 (14.7%)
0.282
PGT-A
Yes
No
248 (55.9%)
196 (44.1%)
58 (52.3%)
53 (47.7%)
190 (57.1%)
143 (42.9%)
0.377
Treatment year
2016
2017
2018
2019
2020
2021
70 (15.8%)
100 (22.5%)
68 (15.3%)
93 (20.9%)
82 (18.5%)
31 (7.0%)
16 (14.4%)
35 (31.5%)
11 (9.9%)
21 (18.9%)
16 (14.4%)
12 (10.8%)
54 (16.2%)
65 (19.5%)
57 (17.1%)
72 (21.6%)
66 (19.8%)
19 (5.7%)
0.023*
Cause of infertility
Advanced maternal age
Male factor
Low reserve/low response
Karyotype alteration/genetic disease
Endometriosis
Polycystic ovarian syndrome
Infertility of unknown origin
Other
195 (43.9%)
129 (29.1%)
32 (7.2%)
14 (3.2%)
12 (2.7%)
11 (2.5%)
22 (5.0%)
29 (8.7%)
46 (41.4%)
33 (29.7%)
12 (10.8%)
6 (5.4%)
4 (3.6%)
2 (1.8%)
5 (4.5%)
3 (2.7%)
149 (44.7%)
96 (28.8%)
20 (6.0%)
8 (2.4%)
8 (2.4%)
9 (2.7%)
17 (5.1%)
26 (7.8%)
0.166
Ovarian stimulation
Days of stimulation
Total gonadotropin dose (UI)
10.8±2.0
2986.2±1275.4
11.1±2.2
3137.7±1376.1
10.7±1.9
2953.7±1252.6
0.138
0.277
Stimulation protocol
Antagonists
Agonists
Progestagens
Clomiphene citrate
Other
Type of trigger
hCG
GnRH agonist
hCG & GnRH agonist
335 (75.5%)
5 (1.1%)
60 (13.5%)
24 (5.4%)
20 (4.5%)

88 (19.8%)
265 (59.7%)
91 (20.5%)
83 (74.8%)
2 (1.8%)
15 (13.5%)
6 (5.4%)
5 (4.5%)

13 (11.7%)
80 (72.1%)
18 (16.2%)
2
52 (75.7%)
3 (0.9%)
45 (13.5%)
18 (5.4%)
15 (4.5%)

75 (22.5%)
185 (55.6%)
73 (21.9%)
0.923
0.007*
Triggering day
E2 levels (pg/ml)
P4 levels (ng/ml)
No. follicles
2108.8±1417.9
0.57 (IQR 0.74)
11.9±5.8
1808.2±1286.9
0.82 (IQR 1.32)
11.0±6.0
2174.5±1438.5
0.55 (IQR 0.64)
12.1±5.7
0.048*
0.015MW*
0.180
Triggering day:
Right Ovary
No. follicles
No. follicles ≥10mm
No. follicles ≥13mm
Biggest follicle (mm)
5.9±3.4
5.5±3.4
4.8±3.2
19.0±2.7
5.5±3.5
5.3±3.6
4.8±3.4
19.1±2.9
6.0±3.4
5.5±3.4
4.8±3.2
19.0±2.6
0.276
0.562
0.990
0.719
Triggering day:
Left Ovary
No. follicles
No. follicles≥10mm
No. follicles≥13mm
Biggest follicle (mm)
5.9±3.0
5.4±3.2
4.8±3.0
18.9±2.9
5.4±3.1
5.1±3.2
4.7±3.1
19.2±3.3
6.0±3.0
5.4±3.2
4.8±3.0
18.9±2.8
0.192
0.396
0.759
0.475