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Table 5 Estimates of prevalence (P), intracluster correlation coefficients (ICC), their respective 95% CI, design effect (Deff), and mean cluster size (n a ) for categorical variables of process during pregnancy

From: Intracluster correlation coefficients for the Brazilian Multicenter Study on Preterm Birth (EMIP): methodological and practical implications

Variable P(%) ICC 95% CI for ICC Deff na
Hospitalization 22.3 0.030 0.008-0.052 10.0 265
Reasons for hospitalization:      
   Emesis 0.6 0.006 0.001-0.013 2.3 264
   Uterine contraction 5.7 0.014 0.002-0.026 5.3 264
   Amniorrhexis 2.2 0.009 0.001-0.017 4.0 264
   Bleeding 2.6 0.008 <0.001-0.016 3.0 264
   Maternal disease 8.9 0.029 0.007-0.050 10.1 264
   Fetal disease 0.8 0.028 0.007-0.049 6.0 264
Syphilis 1.6 0.004 <0.001-0.009 1.7 265
Anemia (registered) 32.0 0.070 0.023-0.118 24.1 238
Treatment for anemia 52.6 0.283 0.138-0.428 74.8 213
Short cervix (US) 1.4 0.011 <0.001-0.022 4.0 209
Cervical insufficiency 2.1 0.005 <0.001-0.012 2.6 230
Cerclage 1.4 0.019 0.003-0.034 5.6 238
Uterine anomalies 0.6 <0.001 <0.001-0.003 0.6 237
Fibroid 1.9 0.002 <0.001-0.006 1.5 233
Maternal diseases:      
   Diabetes 5.7 0.027 0.006-0.047 7.8 254
   Gestational hypertension 7.7 0.025 0.006-0.045 9.4 254
   Preeclampsia/eclampsia/HELLP 16.2 0.062 0.019-0.104 22.5 254
   Chronic hypertension 5.7 0.007 <0.001-0.014 2.8 254
   Other chronic infection 0.7 0.010 0.001-0.020 4.5 254
   Thyroid diseases 1.6 0.027 0.006-0.047 8.2 254
   Renal disease 1.2 0.008 <0.001-0.015 3.1 254
   Sickle cell anemia 0.3 0.002 <0.001-0.006 1.5 254
   Other chronic anemia 0.5 <0.001 <0.001-0.003 0.7 254
   Cardiac disease 1.1 0.003 <0.001-0.008 1.9 254
   Lung disease 1.5 0.009 <0.001-0.017 3.8 254
   Epilepsy 0.6 0.001 <0.001-0.004 1.5 254
   Systemic lupus erythematous 0.5 0.020 0.004-0.036 4.6 254
   Other collagenoses 0.2 0.001 <0.001-0.004 1.4 254
   Digestive disease 0.6 0.006 <0.001-0.013 3.1 254
   Bariatric surgery <0.1 <0.001 <0.001-0.003 0.8 254
   Psychiatric disease 1.0 0.015 0.003-0.028 5.4 254
   Orthopedic disease 0.2 <0.001 <0.001-0.003 0.9 254
   Neoplasms 0.2 0.001 <0.001-0.004 1.4 254
   Thrombosis or thrombophilia 0.4 0.006 <0.001-0.013 2.4 254
Fetal malformation 5.5 0.146 0.057-0.236 35.9 246
Fetal growth restriction 9.3 0.019 0.004-0.035 6.9 246
Other fetal morbidity 7.4 0.386 0.219-0.554 101.5 246
Triplets 2.0 <0.001 <0.001-0.030 1.0 22
Infertility treatment 4.4 <0.001 <0.001-0.031 0.9 22
Multiple monochorionic pregnancy 35.8 0.046 <0.001-0.111 2.0 18
Multiple monoamniotic pregnancy 5.8 0.038 <0.001-0.098 1.9 18
Twin-to-twin transfusion syndrome 5.4 <0.001 <0.001-0.036 0.9 18