Skip to main content
. 2020 Mar 9;65(12):821–834. doi: 10.1177/0706743720904860

Table 1.

Potential Moderators of the Effect of Antenatal Benzodiazepine Exposure on Delivery Outcomes.

Analysis No. of Studies Within Group Effect of Moderator
Heterogeneity
Odds Ratio or Mean Difference (95% CI)a P value Q(df) Within P Value I 2 (Percentage of Variance Explained) Q(df) Between P Value I 2 (Percentage of Variance Explained)
Spontaneous abortion
 All studies 5 1.86 (1.43 to 2.42) <0.001 16.834 0.002 76.0
 Study Quality 0.021 0.89 0.0
  Above quality threshold 4 1.85 (1.3 to, 2.49) <0.001 16.333 0.001 82.0
  Below quality threshold 1 1.93 (1.10 to 3.40) 0.02
Timing of BZD exposure 16.192 <0.001 87.6
  Any time in pregnancy 3 2.30 (1.79 to 2.96) <0.001 0.632 0.73 0.0
  First trimester 1 1.40 (1.26 to 1.57) <0.001
  Up to 22 weeks gestation 1 1.91 (1.54 to 2.37) <0.001
 Any adjusted data 3.171 0.07 68.5
  Adjusted findings 2 1.61 (1.19 to 2.18) 0.002 6.241 0.01 84.0
  Unadjusted findings 3 2.30 (1.79 to 2.96) <0.001 0.632 0.73 0.0
 Exposure to other psychotropics 14.961 <0.001 93.3
  No, exclusion criteria 1 1.40 (1.26 to 1.57) <0.001
  Not specified/assessed 4 2.07 (1.76 to 2.44) <0.001 1.863 0.60 0.0
 Controlled for psychiatric diagnoses 16.192 <0.001 87.6
  Yes, adjusted 1 1.91 (1.54 to 2.37) <0.001
  Exclusion criteria 1 1.40 (1.26 to 1.57) <0.001
  Not specified/assessed 3 2.30 (1.79 to 2.96) <0.001 0.632 0.73 0.0
 Country 3.632 0.16 44.9
  North America 2 2.40 (1.82 to 3.17) <0.001 0.171 0.68 0.0
  Europe 2 1.61 (1.19 to 2.18) 0.002 6.241 0.01 84.0
  Other 1 1.93 (1.10 to 3.40) 0.02
Preterm birth
 All studies 6 1.96 (1.25 to 3.08) 0.004 28.945 <0.001 83.0
 Study quality
  Above quality threshold 6 1.96 (1.25 to 3.08) 0.004 28.945 <0.001 83.0
  Below quality threshold 0
 Timing of BZD exposure 0.451 0.50 0.0
  Any time in pregnancy 5 2.05 (1.05 to 3.99) 0.04 25.964 <0.001 85.0
  Second and/or third trimester 1 1.62 (1.37 to 1.91) <0.001
 Any adjusted data
  Adjusted findings 6 1.96 (1.25 to 3.08) 0.004 28.945 <0.001 83.0
  Unadjusted findings 0
 Exposure to other psychotropics 1.811 0.18 44.9
  Yes, adjusted 3 1.41 (0.95 to 2.10) 0.09 1.312 0.52 0.0
  Not specified/assessed 3 2.51 (1.20 to 5.27) 0.01 26.312 <0.001 92.0
 Controlled for psychiatric diagnoses 1.811 0.18 44.9
  Yes, adjusted 3 1.41 (0.95 to 2.10) 0.09 1.312 0.52 0.0
  Not specified/assessed 3 2.51 (1.20 to 5.27) 0.01 26.312 <0.001 92.0
 Country 1.021 0.31 1.5
  North America 3 2.71 (0.96 to 7.65) 0.06 13.452 0.001 85.0
  Europe 3 1.58 (1.36 to 1.83) <0.001 1.142 0.57 0.0
  Other 0
Birth weight
 All studies 5 −151.35 (−329.73 to 27.03) 0.10 31.904 <0.001 87.0
 Study quality 2.841 0.09 64.7
  Above quality threshold 4 −204.65 (−444.70 to 35.39) 0.09 23.024 <0.001 87.0
  Below quality threshold 1 15.40 (−73.93 to 104.73) 0.74
 Timing of BZD exposure
  Any time in pregnancy 5 −151.35 (−329.73 to 27.03) 0.10 31.904 <0.001 87.0
  First trimester 0
  Second and/or third trimester 0
 Any adjusted data 0.031 0.86 0.0
  Adjusted findings 1 −137.77 (−226.52 to −49.02) 0.002
  Unadjusted findings 4 −163.89 (−437.83 to 110.04) 0.24 30.103 <0.001 90.0
 Exposure to other psychotropics 0.001 0.98 0.0
  No, exclusion criteria 3 −143.47 (−478.13 to 191.20) 0.40 28.382 <0.001 93.0
  Not specified/assessed 2 −147.14 (−231.77 to −62.51) <0.001 0.471 0.49 0.0
 Controlled for psychiatric diagnoses 0.001 0.98 0.0
  Yes (exclusion criteria) 2 −147.14 (−231.77 to −62.51) <0.001 0.471 0.49 0.0
  No (not specified/assessed) 3 −143.47 (−478.13 to 191.20) 0.40 28.382 <0.001 93.0
 Country 6.952 0.03 71.2
  North America 2 −233.02 (−873.62 to 407.58) 0.48 22.291 <0.001 96.0
  Europe 2 −147.14 (−231.77 to −62.51) <0.001 0.471 0.49 0.0
  Other 1 15.40 (−73.93 to 104.73) 0.74
Low birth weight
 All studies 6 2.34 (1.41 to 3.88) 0.001 32.404 <0.001 85.0
 Study quality
  Above quality threshold 6 2.34 (1.41 to 3.88) 0.001 32.404 <0.001 85.0
  Below quality threshold 0
 Timing of BZD exposure 3.621 0.06 72.4
  Any time in pregnancy 5 2.70 (1.42 to 5.15) 0.003 22.414 <0.001 82.0
  Second and/or third trimester 1 1.40 (1.14 to 1.72) 0.001
 Any adjusted data
  Adjusted findings 6 2.34 (1.41 to 3.88) 0.001 32.404 <0.001 85.0
  Unadjusted findings 0
 Exposure to other psychotropics 0.171 0.68 0.0
  Yes, adjusted 3 2.06 (1.10 to 3.89) 0.02 4.162 0.13 52.0
  Not specified/assessed 3 2.57 (1.11 to 5.95) 0.03 28.182 <0.001 93.0
 Controlled for psychiatric diagnoses 0.171 0.68 0.0
  Yes 3 2.06 (1.10 to 3.89) 0.02 4.162 0.13 52.0
  No 3 2.57 (1.11 to 5.95) 0.03 28.182 <0.001 93.0
 Country 9.891 0.002 89.9
  North America 3 4.48 (2.28 to 8.82) <0.001 4.082 0.13 51.0
  Europe 3 1.46 (1.23 to 1.74) <0.001 1.302 0.52 0.0
 Other 0
Gestational age
 All studies 5 −0.49 (−1.18 to 0.19) 0.16 44.354 <0.001 91.0
 Study quality 0.741 0.39 0.0
  Above quality threshold 4 −0.62 (−1.76 to 0.52) 0.29 41.803 <0.001 93.0
  Below quality threshold 1 −0.10 (−0.40 to 0.20) 0.51
 Timing of BZD exposure
  Any time in pregnancy 5 −0.49 (−1.18 to 0.19) 0.16 44.354 <0.001
  First trimester 0
  Second and/or third trimester 0
 Any adjusted data 1.521 0.22 34.2
  Adjusted findings 2 −1.47 (−3.82 to 0.88) 0.22 34.021 <0.001 97.0
  Unadjusted findings 3 0.02 (−0.30 to 0.35) 0.90 2.322 0.31 14.0
 Exposure to other psychotropics 0.331 0.57 0.0
  Yes, exclusion criteria 2 −0.28 (−0.52 to −0.05) 0.02 0.371 0.54 0.0
  Not specified/assessed 3 −0.75 (−2.32 to 0.83) 0.35 43.952 <0.001 95.0
 Controlled for psychiatric diagnoses 0.331 0.57 0.0
  Yes, exclusion criteria 2 −0.28 (−0.52 to −0.05) 0.02 0.371 0.54 0.0
  Not specified/assessed 3 −0.75 (−2.32 to 0.83) 0.35 43.952 <0.001 95.0
 Country 1.192 0.55 0.0
  North America 2 −1.10 (−4.23 to 2.04) 0.49 35.731 <0.001 97.0
  Europe 2 −0.28 (−0.52 to −0.05) 0.02 0.371 0.54 0.0
  Other 1 −0.10 (−0.40 to 0.20) 0.51

Note. GA = gestational age; SGA = small for gestational age.

a Pooled effect size estimated using random-effects model.

b Other countries include Australia, Israel, Singapore, and Taiwan.