Objective To investigate the clinical characteristics of Rh-negative parturients of Han nationality during pregnancy so as to provide a clinical basis for regulating the management of pregnancy and reducing occurrence of fetal and neonatal hemolytic disease (HDFN) caused by maternal and infant blood group incomaptibility.

Methods The clinical data of 271 hospitalized Rh-negative pregnant women and 270 delivered neonates in Department of Obstetrics were retrospectively analyzed. A total of 257 neonates (95.2%) underwent hemolysis examination. According to the results of neonatal hemolysis examination, neonates with all negative hemolysis results were included in group A (n=210), and those with positive antibody release test were included in group B (n=47). In group B, those with negative direct anti-human globulin test were included in group B1 (n=21), and those with positive direct anti-human globulin test were included in group B2 (n=26). The transfer rate, serum immunoglobulin G (IgG) anti-D titer, delivery mode, gestational age, birth weight and transfer rate of neonatal intensive care unit (NICU) were compared between group B and group A, and between group B2 and group B1.

Results Among 270 newborns, the proportion of Rh-positive and Rh-negative neonates was 88.9% and 8.1%, respectively. The proportions of newborns with type A, B, O and AB blood were 28.5%, 25.2%, 31.5% and 11.8%, respectively. The negative and positive rates of IgG anti-D titer in 271 pregnant women were 85.2% and 10.4%, respectively. The preterm birth rate, cesarean section rate, neonatal transfer rate to NICU, positive rate of IgG anti-D and proportion of neonates with fetomaternal ABO blood group incompatibility in pregnant women in the group A were lower than those in the group B (P < 0.05). The preterm birth rate, cesarean section rate and positive rate of IgG anti-D in pregnant women in the group B1 were lower than those in group B2, and the gestational age and birth weight of newborns in the group B1 were higher than those in group B2 (P < 0.05). The proportion of neonates with fetomaternal ABO blood group incompatibility in the group B1 was higher than that in the group B2 (P < 0.05). There was no significant difference in the transfer rates of neonates to NICU and pregnant women from other hospitals (P>0.05).

Conclusion Maternal and infant Rh incompatibility is easy to cause fetal and neonatal hemolytic disease, which increases the rate of premature delivery, cesarean section and neonatal transfer to NICU, and seriously affects the maternal and infant pregnancy outcomes. Therefore, clinical management should be strengthened to improve the pregnancy outcomes.