Table 3: Study population of included studies alongside predictors Table 3: Study population of included studies alongside predictors Table 3: Study population of included studies alongside predictors Table 3: Study population of included studies alongside predictors
Study Author Study Population Candidate Predictors Predictors in Final Model
Ahmadzia et al., 201814
Intraoperative and postoperative blood transfusion
Maternal age (extremes <21 or >36), BMI at delivery, Number of previous term deliveries, Gestational age >37 weeks, total years of schooling, African American ethnicity, insurance status for prenatal care, white blood cell count, platelet count, haematocrit, previous cesarean delivery, asthma, heart disease, connective tissue disorder, hypertensive disorder (gestational hypertension/preeclampsia/HELLP), abruption, non-elective caesarean delivery, use of general anaesthesia, failure to progress, preeclampsia/eclampsia or HELLP, abnormal placentation, intrapartum antibiotic use (including treatment for chorioamnionitis or prophylaxis for GBS/caesarean delivery)
Model 1 & 2: Maternal Age, Body Mass Index (BMI, kg/m2), Platelets x103, Haematocrit (%), Gestational hypertension or Preeclampsia, HELLP, History of asthma, Suspected Abruption, African American, Insurance, Gestational age <37 weeks, 3 or more previous term deliveries, Heart disease, Number prior caesarean deliveries Model 2 also contained: non-elective repeat caesarean delivery, use of general anaesthesia, failure to progress, preeclampsia/eclampsia or HELLP, abnormal placentation, intrapartum antibiotic use
Chi et al., 201617 Parturient patients with complete prenatal examination data Age, BMI, Multiplets, Hypertension family history, Adverse maternal history, History of abdominal operation, Hypertensive disorder complicating pregnancy, Gestational diabetes mellitus, Giant baby, Amniotic fluid, Myoma of uterus, Placenta praevia, Placental abruption, Retained placenta, Adherent placenta, Threatened premature labour, Abnormal pelvic canal, Haemoglobin, Platelet count, Caesarean delivery, Placenta factor Multiplets, Hypertension family history, Adverse maternal history, History of abdominal operation, Hypertensive disorder complicating pregnancy, Giant baby, Amniotic fluid, Myoma of uterus, Abnormal pelvic canal, Threatened premature labour, Haemoglobin ≤ 100, Platelet Count < 100x10^9, Age ≥ 35, BMI ≥ 25, Pregnancy bleeding history
Dunkerton et al., 201818 All caesareans at a single university hospital trust in U.K Previous Caesarean, antepartum/intrapartum haemorrhage, emergency caesarean, age ≥40y, maternal sepsis, suspected scar dehiscence, second-stage section, polyhydramnios, macrosomia, fibroids, preeclampsia/pregnancy induced hypertension, multiple pregnancies, previous three caesarean sections, Asian ethnicity, grandmultiparity, placenta praevia, suspected abruption Placenta praevia, previous caesarean, antepartum haemorrhage, BMI >35, Emergency caesarean section, Asian ethnicity, Multiple Pregnancy, grandmultiparity, pregnancy induced hypertension/Pre-eclampsia
Kim et al., 201719 Patients with placenta praevia who underwent caesarean section Maternal age, BMI, parity, Gestational age, previous caesarean, placental abruption, previous uterine surgery, twin pregnancy, artificial abortion, anterior placenta, cervical vascularity, Suspicion of placental adhesion Gestational age, previous caesarean, anterior placenta, cervical vascularity, suspicion of placental adhesion
Lee et al., 201820 Pregnant women with placenta praevia Maternal age at delivery, Parity, BMI, Number of previous uterine curettages, Previous uterine surgery (caesarean or myomectomy), Presence of uterine myoma, Cervical length within a week before delivery, Gestational age at first episode of AP bleed (after 20 weeks), Number of incidences of antepartum bleeding (after 20w), Need for emergency CS, Fetal presentation, Placental type (complete or incomplete), Location (anterior or posterior), Multiple lacunae (≳4 defined as an irregular area of low echogenicity larger than 1x1cm in placental parenchyma), Lack of translucent zone (clear zone defined as the line of low echogenicity between myometrium and placenta), Uteroplacental hypervascularity evident on colour doppler imaging Maternal age ≥35 years, Antepartum bleeding, fetal non-cephalic presentation, complete placenta praevia, anterior placenta, Multiple lacunae ≥4, Uteroplacental hypervascularity
Prata et al., 201121 Women anticipating a singleton vaginal delivery of gestational age >36 weeks Maternal age, Education, Nulliparity, Previous antenatal care, PPH in previous pregnancy, History of obstetric complications, Intact membranes, Anaemia (measured by blood collected after enrolment and defined as antepartum Hb at or below 11mg/dl), cervical dilatation, Vaginal delivery with instruments, Episiotomy, Labour augmentation, Retained placenta, Vaginal tears, Fetal macrosomia (>3500g), Length of 1st and 2nd stage, Absence of AMTSL (a protocol), Use of uterotonics, Cord clamping, Cord traction, Uterine massage Elevated number of antenatal care visits, history of PPH, anaemia, labour augmentation, retained placenta, length of 1st and 2nd stage, non-use of uterotonics in the 3rd stage and cord traction
Rubio-Alvarez et al., 201822 Women with singleton pregnancies who had vaginal birth Age, BMI, Antepartum haemoglobin, Previous caesarean, Primiparity, Instrumental birth, Duration of first stage, duration of second stage of labour (hours), Use of regional analgesia, Active management (5IU intraoperative oxytocin and consequent controlled umbilical cord traction), Manual removal of placenta, Episiotomy or vaginal tear, Gestational age (weeks)and Neonatal birthweight(g) Primiparity, Maternal age, Duration of first stage, Duration of second stage, Neonatal birthweight and Antepartum haemorrhage
Tsu 199423
Women with singleton vertex deliveries and spontaneous onset of labour
Advanced maternal age (>35), Low parity (0,1), Poor obstetric outcome in preceding pregnancy, Anaemia during current pregnancy (antenatal haemoglobin <12g/dL) and Admission to hospital for any pregnancy related problem before onset of labour
Combination 1: Poor obstetric outcome in last pregnancy or antenatal admission to hospital for a pregnancy related problem Combination 2: Poor obstetric outcome in last pregnancy or antenatal admission to hospital for a pregnancy related problem or low haemoglobin Combination 3: any 2 or more risk factors (as listed under ‘Candidate Predictors’) Combination 4: any 1 or more risk factors (as listed under ‘Candidate Predictors’)
Yoon et al., 201424 Singleton pregnancy women with placenta praevia delivered by caesarean section Type of praevia: partialis and totalis, Location of praevia (posterior, lateral and anterior), Lacunae (classified into 4 grades (0-3)), Echolucent area (intact or absent) Hypervascularity (normal, moderately increased intraplacental vascularity and severe uteroplacental hypervascularity), Bladder-uterine interface (intact or interrupted) Maternal age (≥ 35), Multiparity, Prior caesarean section, Prior praevia, Prior abortion, Antepartum bleeding Type of placenta praevia, Lacunae, Hypervascularity, Multiparity, Prior praevia, Prior caesarean section