Analysis of Pregnancy Outcomes in Patients Exhibiting Recurrent Miscarriage With Concurrent Low-Titer Antiphospholipid Antibodies

Abstract

Background: Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombotic events and adverse pregnancy outcomes, often associated with elevated antiphospholipid antibodies (aPLs). The 2023 ACR/EULAR criteria for APS necessitate persistent medium to high titers of aPLs for laboratory confirmation. However, the impact of persistently low-titer aPLs in recurrent miscarriage (RM) patients remains controversial. This study aims to analyze the effect of treatment on pregnancy outcomes and maternal-fetal complications in patients with low-titer aPLs.

Methods: The study encompassed 252 pregnancies in 237 RM patients tested for aPLs at the Third Hospital of Guangzhou Medical University from January 2018 to July 2022. Patients were divided into two groups based on aPLs titers: 86 with low-titer aPLs (92 pregnancies) and 151 aPLs-negative (160 pregnancies). Of the low-titer group, 71 received treatment, while 21 and all aPLs-negative patients did not. Seventy-one treated patients with low-titer aPLs were divided into two groups. Group A (n = 15) received a standard treatment regimen that included low-dose aspirin (LDA) and low-molecular-weight heparin (LMWH). In contrast, Group B (n = 56) received a multidrug regimen, which included hydroxychloroquine (HCQ) and/or glucocorticoids (GC) and/or intravenous immunoglobulin (IVIG) in addition to the standard treatment of LDA and LMWH. Pregnancy outcomes and maternal-fetal complications were subsequently compared.

Results: The highest positivity rates were for aCL-IgM (76.2% in the untreated low-titer aPLs group and 81.7% in the treated low-titer aPLs group), followed by aβ2GPI-IgM (23.8% in the untreated low-titer aPL group and 11.4% in the treated low-titer aPLs group), and LA (5.6% in the untreated low-titer aPLs group and 3.3% in the treated low-titer aPLs group). Single antibody positivity was 90.5% in the untreated low-titer aPL group and 87.3% in the treated low-titer aPLs group, with double positivity at 9.5% in the untreated low-titer aPLs group and 12.7% in the treated low-titer aPLs group. No triple positivity was detected. The treated low-titer aPLs group had more previous miscarriages (p < 0.05) and a higher ANA positivity rate (p < 0.05) than the aPLs-negative group. Additionally, the treated low-titer aPLs group had lower complement levels than the aPLs-negative group. Immunoglobulin IgM levels were higher in both the untreated and treated low-titer aPL groups compared to the aPLs-negative group (p < 0.05). Post treatment, the live birth rate in the low-titer group significantly exceeded that of the untreated group (67.6% vs. 33.3%; p = 0.005). The miscarriage rate was notably lower in untreated low-titer patients compared to aPLs-negative patients (32.4% vs. 66.7%; p = 0.005). No significant differences were observed in maternal or fetal complications between the groups. In the standard treatment group (Group A), there were 8 (53.3%) live births, whereas the multidrug treatment group (Group B) had 40 (71.4%) live births, a significantly higher rate than in the standard treatment group, although the difference lacked statistical significance.

Conclusions: The study indicates that untreated RM patients with low-titer positive aPLs have a higher recurrence of miscarriage compared to the aPLs-negative RM group. However, recurrence significantly decreases following appropriate intervention, suggesting the benefits of treatment for RM patients with low-titer aPLs.

Keywords: low‐titer antiphospholipid antibodies; pregnancy outcome; recurrent miscarriage; therapy.