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. 2020 Apr 24;8:191. doi: 10.3389/fped.2020.00191

Table 1.

The characteristics of the study population, pumping performance and OOL-II related information.

Characteristics n Mean ± SD, M (P25, P75) or n (%)
Mothers' age (years) 30 32.9 ± 4.5
Cesarean delivery 30 19 (63.3)
After IVF-ET 30 7 (23.3)
Multipara 30 9 (30.0)
Gestational ages (weeks) 30 29.7 ± 1.8
Birth weight (g) 37 1235.7 ± 260.8
Multiple birth 30 7 (23.3)
Pre-pregnancy BMI (kg/m2) 30 24.1 ± 4.5
Weight gain during pregnancy (kg) 30 8.0 ± 4.2
Drinking alcohol or smoking during pregnancy or lactation 30 0 (0.0)
Maternal risk factor for preterm birth 30 28 (93.3)
   Premature rupture of membranes 30 5 (16.7)
   Pre-eclampsia/eclampsia 30 3 (10.0)
   Maternal diabetes 30 1 (3.3)
   Infection 30 3 (10.0)
   Placenta previa, vaginal bleeding 30 1 (3.3)
   Placental abruption 30 1 (3.3)
   ≥ 2 maternal risk factors 30 14 (46.7)
Breast inflamation or surgery 30 0 (0.0)
Gestational ages ≤ 30 weeks 37 22 (59.5)
Birth weight <1,500 g 37 28 (75.8)
First pumping postpartum (h) 30 7.6 (4.6, 10.3)
Time to establish OOL-II
   After birth (h) 30 75.4 (60.7, 83.9)
   After 1st pumping (h) 30 65.8 (56.6, 76.5)
Number of pumping sessions from birth to the OOL-II (times) 30 16.0 (13.8, 21.0)
Cumulative duration of pumping until the OOL-II (h) 30 4.0 (3.4, 5.3)
Breast pumping frequency (times/d, within 42 d after delivery) 30 6.7 ± 0.7

IVF-ET, in vitro fertilization and embryo transfer; BMI, body mass index; OOL-II, onset of lactogenesis II.