Table 1 Critical appraisal of included studies

Landau et al. (54), 1950, United States

Observational quality improvement study

87 infants delivered by CS after introducing a new procedure.

Extra-uterine placental transfusion (placenta suspended above the infant). DCC when cord collapsed (n = 87).

No control-group.

Placenta weight before and after suspension.

Neonatal deaths caused by “secondary shock” (assumed to be Respiratory Distress Syndrome / haematogenic shock)

No incidences of “secondary shock” after implementing the procedure. Mortality rate was 2.3%.

Reported overall mortality rate after CS at the time was 8–9%

Detailed description of the procedure. Maternal outcomes not reported. No mention of recruitment, inclusion criteria or confounders. No statistical analyses performed. Small sample size

Do not qualify as evidence base for intervention development

Secher & Karlberg (55), 1962, Sweden / Denmark

Observational study

30 infants, 10 delivered by CS and 20 delivered vaginally (two control groups)

Extra-uterine placental transfusion after CS (n = 10) vs. after vaginal birth (n = 10). Cord temporarily clamped at birth, opened after suspending placenta above infant. Measured weight change of infant during transfusion.

Control 2 (n = 10): Measured residual placenta blood volume after transfusion in vaginal birth.

Infant weight change from birth until cord clamping (during extra-uterine placental transfusion), estimated transfused blood volume

No “essential” difference in infant weight change between the groups.

Correlation between birthweight and transfused blood volume.

Detailed description of the procedure. Infant and maternal outcomes not reported. No mention of recruitment, inclusion criteria or confounders. No statistical analyses performed. Small sample size

Do not qualify as evidence base for intervention development

Kuehne et al. (47), 2018, Germany

Retrospective cohort study

60 preterm infants delivered by CS, gestational age less than 32 weeks (40 in the experimental group and 20 in the comparison group)

Extra-uterine placental transfusion and DCC after initiation of respiratory support, placenta kept above the infant (n = 40) vs. DCC/ umbilical cord milking before respiratory support (n = 20)

Apgar scores, cord-clamping time, grade of intraventricular haemorrhage, bronchopulmonary disease, necrotising enterocolitis or spontaneous intestinal perforation requiring surgery, peak serum-bilirubin levels, blood transfusions, survival until discharge.

Subgroup: Infant saturation and HR during stabilisation

No statistically significant differences in outcome parameters between the groups.

Detailed description of the method used for the experimental group, not for the control group. Infant outcomes only. No adjustment for confounders. Non-randomised design, small sample size.

Qualify as evidence base for intervention development

Welsh et al. (48), 2020 United States

Pilot study with matched historical control

30 mother-infant couples who underwent uncomplicated term CS in regional anaesthesia

DCC for 3–4 min after intact-cord placental delivery, placenta kept at same level as infant (n = 15) vs. ICC before 30 s (n = 15)

Safety: maternal estimated blood loss, newborn Apgar scores, temperatures, transcutaneous bilirubin levels, need for phototherapy, admission to NICU

Feasibility: proportion of completed protocols, maternal satisfaction and clinician’s comfort with the procedure, mean placenta removal time, cord clamping time

No significant between-group differences in safety parameters.

Protocol completed in 94% of deliveries. High maternal satisfaction. High clinician comfort.

Covers both maternal and infant outcomes. Detailed description of the method used. Small sample size. Non-randomised design, no mention or adjustment for confounders.

Qualify as evidence base for intervention development