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. 2022 Aug 6;22:624. doi: 10.1186/s12884-022-04952-0

Table 3.

Stepwise multiple linear regression analysis for the effect of independent variables on rapid, tonic, and endurance contraction

Variables Rapid contraction Tonic contraction Endurance contraction
B β t B β t B β t
(constant) 38.668 24.032 28.967 24.350 25.298 24.770
Age -.298 -.066 -9.123*** -.354 -.107 -14.860*** -.310 -.109 -15.021***

BMI

(kg/m2)

.546 .085 12.877*** .366 .078 11.826*** .309 .076 11.503***
Parity 1 (ref.) (ref.) (ref.)
2 2.117 .055 7.578*** .905 .032 4.438*** .690 .029 3.962***
3 2.553 .025 3.650*** 1.316 .018 2.576* 1.367 .021 3.135**
 ≥ 4
Education  ≤ 12 (ref.) (ref.) (ref.)
 > 12 2.768 .058 8.743*** 3.141 .090 13.586*** 2.391 .080 12.116***
GWG .046 .019 2.758**
NW -1.199 -.034 -5.203*** -.380 -.015 -2.258* -.436 -.020 -2.964**
NOF 1 (ref.) (ref.) (ref.)
 ≥ 2
DM CS (ref.) (ref.) (ref.)
NIVD -10.639 -.292 -40.137*** -8.169 -.305 -42.202*** -7.445 -.324 -45.060***
EP -12.060 -.216 -30.245*** -9.164 -.224 -31.470*** -8.385 -.239 -33.729***
FD -20.159 -.176 -26.474*** -15.238 -.182 -27.403*** -13.342 -.185 -28.113***
F 281.255*** 304.462*** 304.302***
R2 0.106 0.114 0.125
adjR2 0.106 0.114 0.125

BMI body mass index, GWG gestational weight gain, NW neonatal weight, NOF number of fetus, DM delivery mode, CS cesarean section, NIVD non-instrumental vaginal delivery, EP episiotomy, FD forceps delivery, B unstandardized beta, β standardized beta, t t test statistic

*p < .05

**p < .01

***p < .001