Influencing factors of lactational insufficiency at 72 hours postpartum and construction of nomogram model

Objective To investigate the influencing factors of lactational insufficiency in 72 hours postpartum and to construct a nomogram model.

Methods A total of 345 puerperae who were hospitalized for delivery were selected as research subjects. According to a ratio of 7 to 3, they were divided into modeling group (242 cases) and validation group (103 cases). Based on the lactation situation at 72 hours postpartum, the modeling group was further divided into lactational insufficiency group (69 cases) and normal lactation group (173 cases). The clinical data of the puerperae were collected. Multivariate Logistic regression model was used to analyze the influencing factors of lactational insufficiency at 72 hours postpartum. R 3.6.3 software was used to construct a nomogram model for predicting lactational insufficiency at 72 hours postpartum. The receiver operating characteristic (ROC) curve and calibration curve were plotted to evaluate the discrimination and consistency of the nomogram model in predicting lactational insufficiency at 72 hours postpartum.

Results There were no significant differences in age, parity, delivery mode, nipple type, and other factors between the modeling group and the validation group (P>0.05). The proportions of primipara, cesarean section, time from delivery to milk expression >1 hour, the number of breastfeeding ≤6 times in 24 hours, and absence of breast massage in the lactational insufficiency group were higher than those in the normal lactation group (P < 0.05). Multivariate Logistic regression model analysis showed that parity, delivery mode, time from delivery to milk expression, and the number of breastfeeding in 24 hours were influencing factors of lactational insufficiency at 72 hours postpartum (OR=3.488, 2.381, 2.442, 2.223, P < 0.05). The ROC curve showed that the area under the curve of the nomogram model in the modeling group and the validation group was 0.844 (95%CI, 0.792 to 0.897) and 0.863 (95%CI, 0.791 to 0.935), respectively. The slope of calibration curve was close to 1, and the Hosmer-Lemeshow goodness-of-fit test showed that the model fitted well (χ²=7.002, 4.560, P=0.429, 0.714).

Conclusion Parity, delivery mode, time from delivery to milk expression, and the number of breastfeeding in 24 hours are influencing factors of lactational insufficiency at 72 hours postpartum. The nomogram prediction model constructed based on these factors has good discrimination and consistency.