Results

Out of 101 women with singleton pregnancies giving birth prior to 34 completed weeks of gestation due to preeclampsia with severe features during the study period, the aPL antibodies status of 55 women was available for analysis. The median gestational age at diagnosis was 31 (IQR 28-33), and the median gestational age at delivery was 32 (IQR (29-34) with a mean birth weight of 1458±568 grams. The study group – aPL-positive group – comprised of 20 women, while the aPL-negative group comprised of 35 women who served as controls. The antibodies distribution of the aPL-positive group is presented in Table 1.
Table 2 displays the demographic and clinical characteristics of the study and control groups. All participants were Caucasian. Women in the study group were younger than controls (30.15±4.64 vs. 34.34±7.02, p=0.01), but with higher gravidity (3, IQR 1.25-4.75, in the study group vs. 2, IQR 1-2, in controls, p=0.01). Medical history of chronic hypertension and diabetic mellitus, pre-gestational or gestational, were comparable between the two groups. There were 2 cases of systemic lupus erythematosus among study group cases and one among controls. Additionally, there was one case of glomerulonephritis and one case of Behҫet’s disease among the study group.
The obstetric outcomes and pregnancy complications for pregnancies in aPL-positive and aPL-negative women are presented in Table 3. Median gestational age at hospitalization was three weeks earlier in aPL-positive women compared with aPL-negative women (29, IQR 26.28–32, vs. 32, IQR 28-33 weeks gestation, respectively, p=0.05). aPL-positive women delivered at significantly earlier gestational age (30, IQR 28.3-32.8 weeks, vs. 33, IQR 30-34 weeks, p=0.02) with lower mean neonatal birth weight compared with those with negative aPL antibodies (1266.7±579.6 grams vs. 1567.3±539.7 grams, respectively, p=0.058). There were two peripartum fetal deaths in our cohort, both to aPL-positive mothers. One case was an antepartum fetal death at 27 weeks gestation of a severely growth-restricted fetus, and the other case was a severely growth-restricted neonate born at 24 weeks gestation who died at two days of age from complications of prematurity. The rate of cesarean section was high and comparable between the groups. Furthermore, women in the aPL-positive group were hospitalized for a longer period after delivery compared with aPL-negative group women (9, IQR 6-12, vs. 7, IQR 6-9 days, respectively, p=0.03).
In order to assess the severity of the disease, we evaluated clinical and laboratory characteristics of preeclampsia with severe features in both groups. Although maximal systolic blood pressure was lower for aPL-positive women compared with aPL-negative controls (149.72±22.6, vs. 170.03±23.1, p=0.004), overall disease severity was more significant for aPL-positive women. Platelet nadir was significantly lower for aPL-positive compared with aPL-negative women (mean 97.2±49.7103/µL vs. 141.3±61.13/µL, respectively, p<0.001) and maximal serum creatinine was higher (1.02±0.32 mg/dL vs. 0.92±0.13 mg/dL, p=0.03). Moreover, both cases of eclampsia occurred in the aPL-positive women. Table 3 outlines the frequency of severe pregnancy complications in both groups.
Twenty neonates were born to aPL-positive mothers, and 35 to aPL-negative mothers (Table 4). Rates of complications of prematurity were comparable between groups, except for higher rates of retinopathy of prematurity in women with positive aPL antibodies (30.0% vs. 5.7%, p=0.02).
As mentioned above, there were two antepartum fetal deaths in our cohort, both to study group mothers. Neonatal death before discharge occurred in one neonate born to an aPL-positive mother and one of 35 neonates born to aPL-negative mothers. Therefore, overall perinatal mortality was higher for aPL-positive women compared with aPL-negative women, although not statistically significant (3 out of 20 (15%) vs. 1 out of 35 (2.8%), p=0.13).