The study population consisted of 165 individuals, of which 68 (41%) were confirmed to have HELLP syndrome and 97 (59%) were confirmed cases of sPE (Table 1). Additionally, 93 (56%) individuals gave birth at or below a GA of 34 weeks and 72 (44%) gave birth after 34 weeks (Table 2). The total sample size in each multivariable prediction model varies based on the available data for each covariate.
No statistically significant difference was observed between mothers diagnosed with sPE and HELLP syndrome with regard to: maximum creatinine levels (mg/dL) (p = 0.78), delivery type (p = 0.16), maternal hemorrhage (p = 0.39), birthweight (g) (p = 0.56), SGA (p = 0.86), IUGR (p = 0.65), Apgar Score (p = 0.08), neonatal death (p = 0.06), prior history of hypertension (p = 0.10), prior history of diabetes (p = 0.93), mean pre-pregnancy weight (lbs) (p = 0.47), maximum systolic blood pressure (mmHg) (p = 0.77), and maximum diastolic blood pressure (mmHg) (p = 0.90) (Table 1). Statistically significant differences were observed between mothers diagnosed with sPE and HELLP syndrome with the following variables related to laboratory measurements: higher maximum LDH (units/L) in the HELLP group (2155.7 ± 3337.9) compared to the sPE group (509.3 ± 411.7) (p < 0.001), higher maximum bilirubin (mg/dL) in the HELLP group (4.1 ± 12.5) compared to the sPE group (0.7 ± 0.4) (p < 0.001), higher maximum AST (units/L) in the HELLP group (625.8 ± 905.9) compared to the sPE group (290.5 ± 394.4) (p < 0.001), higher maximum ALT (units/L) in the HELLP group (580.5 ± 1316.0) compared to the sPE group (262.5 ± 341.5) (p = 0.001), and minimum platelet count ( x 109/ L) in the HELLP group (47.5 ± 20.2) compared to the sPE group (101.9 ± 68.1) (p < 0.001) (Table 1).
No statistically significant difference was observed between mothers who gave birth at or below 34 weeks and those who gave birth later than 34 weeks with the following variables related to medical history: prior history of hypertension (p = 0.60), prior history of diabetes (p = 0.36), mean pre-pregnancy weight (lbs) (p = 0.90), and maximum diastolic blood pressure (mmHg) (p = 0.39) (Table 2). However, a statistically significant difference was noted for maximum systolic blood pressure (mmHg), with a higher systolic blood pressure in the earlier delivery group (165.5 ± 21.7) compared to the later delivery group (157.3 ± 25.5) (p = 0.030) (Table 2). No statistically significant difference was observed between the two delivery groups among variables related to laboratory measurements: maximum LDH (units/L) (p = 0.09), maximum bilirubin (mg/dL) (p = 0.74), maximum AST (units/L) (p = 0.83), maximum ALT (units/L)(p = 0.70), maximum creatinine levels (mg/dL) (p = 0.43), and minimum platelet count ( x 109/ L) (p = 0.39) (Table 2). Statistically significant differences were detected for: delivery type, with less vaginal and vacuum assisted deliveries and more Cesarean Section deliveries in the early delivery group compared to the later delivery group (p = 0.010), lower birth weight (g) in the earlier delivery group (1327.1 ± 590.5) compared to the later delivery group (2769.5 ± 699.7) (p < 0.001), greater frequency of SGA in the earlier delivery group (36.3%) compared to the later delivery group (8.5%) (p < 0.001), greater frequency of IUGR in the earlier delivery group (21.1%) compared to the later delivery group (4.5%) (p = 0.003), and greater frequency of neonatal death in the earlier delivery group (17.2%) compared to the later delivery group (4.2%) (p = 0.009) (Table 2). No significant differences were observed for maternal hemorrhage (p = 0.17) or Apgar Score (p = 0.11) (Table 2).
Table 1
Demographic and Clinical Characteristics of the Study Population Categorized by ACOG Diagnosis
Variablea | N | sPE | N | HELLP Syndrome | p-valueb |
Demographic Characteristics |
Maternal age, years | 97 | 30.8 (± 3.7) | 68 | 30.1 (± 4.0) | 0.21 |
White | 90 | 89 (98.9%) | 64 | 63 (98.4%) | > 0.99 |
Nulliparity | 96 | 84 (87.5%) | 66 | 59 (89.4%) | 0.71 |
Medical History |
History of hypertension | 91 | 11 (12.1%) | 67 | 3 (4.5%) | 0.10 |
History of diabetes | 94 | 6 (6.4%) | 66 | 4 (6.1%) | > 0.99 |
Pre-pregnancy weight, lbs | 90 | 147.3 (± 29.9) | 57 | 148.1 (± 38.1) | 0.47 |
Maximum systolic blood pressure (mmHg) | 93 | 161.5 (± 24.3) | 67 | 162.6 (± 23.0) | 0.77 |
Maximum diastolic blood Pressure (mmHg) | 93 | 98.7 (± 12.0) | 67 | 99.2 (± 15.0) | 0.90 |
Laboratory Measurements |
Maximum LDH (units/L) | 40 | 509.3 (± 411.7) | 50 | 2155.7 (± 3337.9) | < 0.01 |
Maximum Bilirubin (mg/dL) | 56 | 0.7 (± 0.4) | 56 | 4.1 (± 12.5) | < 0.01 |
Maximum AST (units/L) | 87 | 290.5 (± 394.4) | 67 | 625.8 (± 905.9) | < 0.01 |
Maximum ALT (units/L) | 78 | 262.5 (± 341.5) | 66 | 580.5 (± 1316.0) | < 0.01 |
Maximum Creatinine (mg/dL) | 74 | 3.6 (± 15.1) | 59 | 5.4 (± 19.2) | 0.78 |
Minimum Platelet Count (x 109/ L) | 89 | 101.9 (± 68.1) | 68 | 47.5 (± 20.2) | < 0.01 |
Perinatal Events |
Delivery Type Vaginal (spontaneous) Cesarean Section Vacuum-Assisted | 87 | 20 (22.9%) 63 (72.4%) 4 (4.6%) | 62 | 8 (12.9%) 53 (85.5%) 1 (1.6%) | 0.17 |
Maternal Hemorrhage | 90 | 4 (4.4%) | 65 | 5 (7.7%) | 0.49 |
Birthweight (g) | 82 | 1989.9 (± 977.9) | 61 | 1925.8 (± 945.4) | 0.56 |
Small for Gestational Age | 80 | 20 (25.0%) | 59 | 14 (23.7%) | 0.86 |
IUGR | 92 | 12 (13.0%) | 64 | 10 (15.6%) | 0.65 |
Apgar Score 0–4 5–10 | 77 | 20 (20.6%) 77 (79.4%) | 57 | 7 (10.3%) 61 (89.7%) | 0.08 |
Neonatal Death | 97 | 15 (15.5%) | 68 | 4 (5.9%) | 0.06 |
Lactate Dehydrogenase (LDH); Aspartate Aminotransferase (AST); Alanine Aminotransferase (ALT); Intrauterine Growth Restriction (IUGR)
a Continuous variables presented as mean (± standard deviation) and categorical variables presented as frequencies (%)
bP-values obtained by t-test or Wilcoxon rank sum for continuous variables as appropriate and by Pearson’s chi-square test or Fisher’s Exact test for categorical variables as appropriate
Table 2
Demographic and Clinical Characteristics of the Study Population Categorized by Gestational Age at Delivery
Variablea | N | Gestational Age > 34 weeks | N | Gestational Age \(\le\) 34 weeks | p-valueb |
Demographic Characteristics |
Maternal Age, years | 72 | 30.8 (± 3.7) | 93 | 30.3 (± 4.0) | 0.31 |
White | 63 | 63 (100%) | 91 | 89 (97.8%) | 0.51 |
Nulliparity | 69 | 62 (89.9%) | 93 | 81 (87.1%) | 0.59 |
Medical History |
History of Hypertension | 67 | 5 (7.5%) | 91 | 9 (9.8%) | 0.60 |
History of diabetes | 70 | 3 (4.3%) | 90 | 7 (7.8%) | 0.52 |
Pre-pregnancy Weight, lbs | 63 | 146.6 (± 31.9) | 84 | 148.4 (± 34.30) | 0.90 |
Maximum Systolic Blood Pressure (mmHg) | 70 | 157.3 (± 25.5) | 90 | 165.5 (± 21.7) | 0.03 |
Maximum Diastolic Blood Pressure (mmHg) | 70 | 97.7 (± 14.0) | 90 | 99.8 (± 2.8) | 0.39 |
Laboratory Measurements |
Maximum LDH (units/L) | 35 | 867.5 (± 994.4) | 55 | 1778.0 (± 3224.4) | 0.09 |
Maximum Bilirubin (mg/dL) | 52 | 1.8 (± 2.5) | 60 | 2.4 (± 12.0) | 0.74 |
Maximum AST (units/L) | 67 | 425.1 (± 620.8) | 87 | 445.1 (± 734.0) | 0.83 |
Maximum ALT (units/L) | 65 | 354.4 (± 533.6) | 79 | 452.6 (± 1169.0) | 0.77 |
Maximum Creatinine (mg/dL) | 58 | 2.6 (± 9.7) | 75 | 5.9 (± 20.9) | 0.43 |
Minimum Platelet Count (x 109/ L) | 70 | 84.2 (± 71.2) | 87 | 73.6 (± 47.7) | 0.77 |
Perinatal Events |
Delivery Type Vaginal (spontaneous) Cesarean Section Vacuum-Assisted | 64 | 15 (23.4%) 44 (68.8%) 5 (7.8%) | 85 | 13 (15.3%) 72 (84.7%) 0 (0%) | 0.008 |
Maternal Hemorrhage | 66 | 6 (9.1%) | 89 | 3 (3.4%) | 0.17 |
Birthweight (g) | 63 | 2769.5 (± 699.7) | 80 | 1327.1 (± 590.5) | < 0.01 |
Small for Gestational Age | 59 | 5 (8.5%) | 80 | 29 (36.3%) | < 0.01 |
IUGR | 66 | 3 (4.5%) | 90 | 19 (21.1%) | < 0.01 |
Apgar Score 0–4 5–10 | 72 | 8 (11.1%) 64 (88.9%) | 93 | 19 (20.4%) 74 (79.6%) | 0.11 |
Neonatal Death | 72 | 3 (4.2%) | 93 | 16 (17.2%) | < 0.01 |
Lactate Dehydrogenase (LDH); Aspartate Aminotransferase (AST); Alanine Aminotransferase (ALT); Intrauterine Growth Restriction (IUGR)
aContinuous variables presented as mean (± standard deviation) and categorical variables presented as frequencies (%)
bP-values obtained by t-test or Wilcoxon rank sum for continuous variables as appropriate and by Pearson’s chi-square test or Fisher’s Exact test for categorical variables as appropriate
Table 3
Predictive Model for Adverse Neonatal Events using ACOG Diagnostic Criteria (Model A)
Variable | Odds Ratio | 95% Confidence Interval | p-value |
ACOG Definition | | | | |
Severe PE | Ref. | Ref. | Ref. | Ref. |
HELLP | 0.52 | 0.25 | 1.08 | 0.08 |
Maximum Systolic Blood Pressure (mmHg) | 1.03 | 1.01 | 1.04 | < 0.01 |
Edema | 2.58 | 1.25 | 5.33 | 0.01 |
Male Infant | 2.09 | 1.01 | 4.35 | 0.05 |
Sensitivity | 70.3% |
Specificity | 64.4% |
AUC | 0.73 (0.65, 0.81) |
n = 147; LR χ2 (4) = 23.03; p = 0.0001; Hosmer Lemeshow χ2 (2) = 0.83, p = 0.66 |
Table 4
Predictive Model for Adverse Neonatal Events using Gestational Age (Model B)
Variable | Odds Ratio | 95% Confidence Interval | p-value |
Gestational Age | | | | |
> 34 weeks | Ref. | Ref. | Ref. | Ref. |
\(\le\) 34 weeks | 8.35 | 3.70 | 18.86 | < 0.01 |
Maximum Systolic Blood Pressure (mmHg) | 1.03 | 1.01 | 1.04 | < 0.01 |
Edema | 2.53 | 1.14 | 5.65 | 0.02 |
Male | 1.47 | 0.66 | 3.26 | 0.35 |
Sensitivity | 75.7% |
Specificity | 76.7% |
AUC | 0.82 (0.75, 0.89) |
n = 147 LR χ2 (4) = 50.07; p < 0.001 Hosmer Lemeshow χ2 (2) = 0.83, p = 0.66 |
Model A - Composite Neonatal Outcome Including Low Birthweight, SGA, IUGR, Apgar Score, and Neonatal Death using ACOG Definition: We observed a nonsignificant reduction in neonatal death (OR = 0.52, 95% CI: 0.25–1.08, p = 0.08, Table 3) for those with HELLP syndrome compared to those with sPE. Maximum systolic blood pressure was significantly higher in those with adverse neonatal outcomes (OR = 1.03, 95% CI: 1.01–1.04, p = 0.001 Table 3). Additionally, those with edema were significantly more likely to have an adverse outcome (OR = 2.58, 95% CI: 1.25–5.33, p = 0.010 Table 3) along with male neonates (OR = 2.09, 95% CI: 1.01–4.53, p = 0.048 Table 3). The AUC for this model was estimated to be 0.73 (95% CI: 0.65–0.81) (Table 3, Fig. 1). As parameterized, the model had a sensitivity of 70.3% and a specificity of 64.4% with a correct classification rate of 67.4% (Table 3).
Model B - Composite Neonatal Outcome Including Low Birthweight, SGA, IUGR, Apgar Score, and Neonatal Death using early delivery (GA): Using early delivery to predict risk of neonatal outcomes, we found a significant increase in the odds of an adverse outcome associated with delivering at ≤ 34 weeks compared to those who delivered at > 34 weeks (OR = 8.53, 95% CI: 3.70-18.86, p < 0.001, Table 4). As before, maximum systolic blood pressure is significantly higher in those with adverse outcomes, independent of GA (OR = 1.03, 95% CI: 1.01–1.04, p = 0.008 Table 4). Additionally, those with edema were significantly more likely to have a neonatal complication, independent of GA, gender, or blood pressure (OR = 2.53, 95% CI: 1.14–5.65, p = 0.023 Table 4). However, male neonates were not at significantly increased risk in this model (OR = 1.47, 95% CI: 0.66–3.26, p = 0.35 Table 4). When examining predictive capacity of the model, we estimated the AUC to be 0.82 (95% CI: 0.75–0.89) (Table 4, Fig. 2). As parameterized, the model had a sensitivity of 75.7% and a specificity of 76.7% with a correct classification rate of 76.2% (Table 4). A comparison of the AUC between Models A and B suggests that they are statistically significantly different (p = 0.031), with the GA-based model showing better predictive ability than the model based on ACOG definitions.