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
ptb<34 0.07 0.85 0.72,1.01 57% 1.83 Nicolaided 2015 0.004* + low
ptb<37 0.18 0.95 0.88,1.02 0% 1.35 - - - low
miscarriage 0.76 0.95 0.69,1.31 0% 0.31 - - - low
sptb<34 0.06 0.83 0.68,1.01 60% 1.86 Nicolaided 2015 0.003* + very low
sptb<37 0.34 0.93 0.8,1.08 0% 0.96 - - - low
SM 0.18 0.72 0.44,1.17 0% 1.34 - - - low
DW <0.00001* 0.25 0.18,0.32 82% 6.82 Dang 2019 <0.00001* + Very low
C 0.87 1.04 0.64,1.71 0% 0.17 - - - low
VI 0.13 1.45 0.9,2.34 23% 1.52 - - - Very low
VD <0.00001* 5.41 4.17,7.02 97% 12.69 Merced2019 <0.0001* + low
<34PPROM 0.56 1.25 0.59,2.64 66% 0.58 Goya2015 0.08 + Very low
PPROM 0.14 1.33 0.91,1.94 63% 1.49 Norman2021 0.62 + Very low
C-section 0.07 1.09 0.99,1.19 8% 1.84 - - - low
VB <0.0001* 1.56 1.32,1.83 93% 5.34 Merced2019 <0.00001* + Very low
intrauterine death or stillbirth 0.48 0.86 1.57,1.30 0% 0.71 - - - low
neonatal death 0.95 0.99 0.68,1.45 0% 0.06 - - - low
<2500 <0.00001* 0.90 0.86,0.95 93% 4.14 Merced2019 0.03* + Very low
<1500 0.98 1.00 0.85,1.19 0% 0.03 - - - low
NE 0.01* 0.57 0.36,0.89 40% 2.45 - - - low
IVH 0.55 1.14 0.73,1.79 0% 0.59 - - - low
RDS 0.93 0.99 0.83,1.19 28% 0.08 - - - low
RE 0.08 2.32 0.9,6.00 40% 1.73 - - - low
S 0.03* 0.64 0.43,0.95 55% 2.21 Norman2021 0.003* + low