Abstract
Objective To create a prediction model for postoperative hemoglobin levels after cesarean delivery,
which could reduce routine use of postoperative laboratory test.
Study Design This was a secondary analysis of a retrospective cohort study of all women who underwent
cesarean delivery (primary or repeat) at or more than 23 weeks' gestation at a single
academic center. The cohort was randomly divided into a training cohort to develop
a prediction model and a validation cohort to test the model in a 2:1 ratio. Variables
with p -value <0.10 were considered for the mixed multivariable linear regression model in
a backward stepwise fashion. We obtained the best cut-off point of the predicted hemoglobin
level to detect severe anemia (postoperative hemoglobin level less than 7.0 g/dL)
in the training cohort. A receiver operating characteristic curve with the area under
a curve was created. We calculated the sensitivity and specificity of the model in
the validation cohort using the best cut-off point obtained in the training cohort
as well as postoperative hemoglobin of 10.0 g/dL.
Results Of 2,930 women, 1,954 (66.6%) and 976 (33.3%) were randomly allocated to training
and validation cohorts. The final model included preoperative hemoglobin level, preoperative
platelet level, quantitative blood loss, height, weight, magnesium administration,
labor, and general anesthesia. The best cut-off to predict severe anemia was predicted
hemoglobin level of 8.57 g/dL in the training cohort. Using this cut-off, the sensitivity
and specificity in the validation cohort were 77% (95% confidence interval [CI]: 56–91%)
and 87% (95% CI: 85–89%), respectively. The use of postpartum hemorrhage yielded the
sensitivity of 58% (95% CI: 37–77%) and specificity 79% (95% CI: 76–81%), respectively.
Conclusion We developed a validated model to predict the postoperative day 1 hemoglobin levels
after cesarean delivery that could assist with identifying women who may not need
postoperative laboratory tests.
Key Points
Postoperative laboratory tests are routine.
A prediction model may allow reduce routine tests.
We developed an accurate mathematical model.
Keywords cesarean delivery - laboratory test - postoperative anemia - prediction
