Results P 95%CI 95%CI I2 RR Exclude the literature name The p values were after the sensitivity analysis Publication bias Quality of evidence
ptd<34 0.06 0.84 0.71,1.00 64% 1.91 Nicolaided 2015 0.002* + moderate
ptd<37 0.17 0.95 0.88,1.02 0% 1.36 - - - moderate
miscarriage 0.40 0.94 0.69,1.30 0% 0.69 - - - moderate
sptd<34 0.06 0.82 0.67,1.01 69% 1.9 Goya2015 0.32 + low
sptd<37 0.32 0.93 0.79,1.08 0% 1 - - - moderate
SM 0.16 0.68 0.4,1.16 0% 1.42 - - - moderate
DW <0.00001* 0.25 0.18,1.32 82% 6.82 Dang 2019 <0.00001* + low
C 0.82 0.94 0.56,1.57 0% 0.23 - - - moderate
VI 0.49 1.2 0.72,1.99 0% 0.69 - - - low
VD <0.00001 6.35 4.72,8.54 98% 12.23 Goya2015 <0.00001*! + high
<34PPROM 0.56 1.25 0.59,2.64 66% 0.58 Goya2015 0.08 + low
PPROM 0.08 1.44 0.96,2.15 70% 1.77 Leim2013 0.004! + low
C-section 0.04* 1.1 1,1.21 2% 2.05 - - - moderate
VB <0.00001* 1.56 1.32,1.82 93% 5.43 Dang 2019 0.32! + low
intrauterine death or stillbirth 0.48 0.86 0.57,1.3 0% 0.71 - - - moderate
neonatal death 0.87 0.97 0.65,1.44 8% 0.16 - - - moderate
<2500 <0.0001* 0.9 0.86,0.95 93% 4.14 Merced 2019 0.03* + low
<1500 0.98 1 0.85,1.19 0% 0.03 - - - moderate
NE 0.01* 0.54 0.34,0.86 45% 2.59 - moderate
IVH 0.63 1.12 0.71,1.77 0% 0.49 - moderate
RDS 0.81 0.98 0.81,1.18 37% 0.24 - moderate
RE 0.11 2.26 0.83,6.12 70% 1.6 + low
S 0.009* 0.57 0.38,0.87 52% 2.61 Merced 2019 0.07 + low