Objective   To explore the clinical characteristics of early-onset preeclampsia (PE) combined with HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, and to improve the capacity for early diagnosis and treatment.

  Methods   Pregnant women who received treatment at Women’s Hospital, School of Medicine, Zhejiang University between March 2014 and October 2021 were retrospectively enrolled. There were two patient groups, the HELLP group consisting of 70 cases of early-onset PE combined with HELLP syndrome and the control group consisting of 140 cases of early-onset PE without HELLP syndrome. Patients in the two groups were matched by age. The general clinical data, characteristics of pathogenesis, and laboratory findings of the patients were collected and the perinatal outcomes of the two groups were compared and analyzed.

  Results   1) There was no significant difference in gravidity, pre-delivery body mass index, years from the last delivery, and family history of diabetes mellitus and hypertension between the two groups. 2) The highest systolic blood pressure, highest diastolic blood pressure during the pregnancy, and the postpartum hospital length-of-stay (P<0.001) in the HELLP group were higher than those in the control group. The gestational age at the time of the diagnosis of PE (P=0.001) and the gestational age at delivery (P<0.001) in the HELLP group were significantly earlier than those in the control group. The difference between the gestational age at the time of blood pressure elevation and that at the time of delivery (P<0.001), and the gestational age difference between the diagnosis of early-onset PE and delivery (P=0.027) were lower than those in the control group. The incidences of eclampsia in the HELLP group, pleural effusion, and ascites were higher than those of the control group. 3) Neonates in the HELLP group had a higher probability of being admitted to NICU and developing cyanotic/pale asphyxia (P<0.001). 4) Before the termination of pregnancy, the HELLP group had higher levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, creatinine, urea, random glucose, lactate dehydrogenase, activated partial thromboplastin time, and the last 24-hour urine protein quantification than those of the control group (all P<0.05), while the platelet (PLT) counts were significantly lower than those of the control group (P<0.001). 5) There was a significant correlation between PLT counts in the second trimester and the onset of HELLP syndrome (P=0.006), with the area under the ROC curve reaching 0.746 (95% CI: 0.596-0.897).

  Conclusion   In comparison with early-onset PE patients without HELLP syndrome, patients with early-onset PE combined with HELLP syndrome are diagnosed for PE at an earlier gestational age, have higher blood pressure, are more prone to serious pregnancy complications, and have longer postpartum hospital length-of-stay and worse neonatal outcomes. Close monitoring of PLT counts of early-onset PE patients in the second trimester may help predict subsequent HELLP syndrome.