Premium
Measuring placental transfusion for term births: weighing babies with cord intact
Author(s) -
Farrar D,
Airey R,
Law GR,
Tuffnell D,
Cattle B,
Duley L
Publication year - 2011
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2010.02781.x
Subject(s) - medicine , umbilical cord , birth weight , confidence interval , blood transfusion , blood volume , cord , obstetrics , pregnancy , surgery , anesthesia , biology , anatomy , genetics
Please cite this paper as: Farrar D, Airey R, Law G, Tuffnell D, Cattle B, Duley L. Measuring placental transfusion for term births: weighing babies with cord intact. BJOG 2011;118:70–75. Objective To estimate the volume and duration of placental transfusion at term. Design Prospective observational study. Setting Maternity unit in Bradford, UK. Population Twenty‐six term births. Methods Babies were weighed with umbilical cord intact using digital scales that record an average weight every 2 seconds. Placental transfusion was calculated from the change in weight between birth and either cord clamping or when weighing stopped. Start and end weights were estimated using both a B‐spline and inspection of graphs. Weight was converted to volume, 1 ml of blood weighing 1.05 g. Main outcome measures Volume and duration of placental transfusion. Results Twenty‐six babies were weighed. Start weights were difficult to determine because of artefacts in the data as the baby was placed on the scales and wrapped. The mean difference in weight was 116 g [95% confidence interval (CI), 72–160 g] using the B‐spline and 87 g (95% CI, 64–110 g) using inspection. Converting this to the mean volume of placental transfusion gave 110 ml (95% CI, 69–152 ml) and 83 ml (95% CI, 61–106 ml), respectively. Placental transfusion was usually complete by 2 minutes, but sometimes continued for up to 5 minutes. Based on the B‐spline, placental transfusion contributed 32 ml (95% CI, 30–33 ml) per kilogram of birth weight to blood volume, but 24 ml (95% CI, 19–32 ml) based on inspection. This equates to 40% (95% CI, 37–42%) and 30% (24–40%), respectively, of total potential blood volume. Conclusion Inspection of the graphs probably underestimates placental transfusion. For term infants, placental transfusion contributes between one‐third and one‐quarter of total potential blood volume at birth.