P-377 Association between antinuclear antibodies and pregnancy prognosis in recurrent pregnancy loss patients
Authors: Yoshihara H , Sugiura-Ogasawara M , Kitaori T , Goto S 
Published: August 2021

Abstract

Study question
Can antinuclear antibody (ANA) affect the subsequent live birth rate in patients with recurrent pregnancy loss (RPL) who have no antiphospholipid antibodies (aPLs)?

Summary answer
ANA did not affect the pregnancy prognosis of RPL women.

What is known already
The prevalence of ANA is well-known to be higher in RPL patients. Our previous study found no difference in the live birth rates of ANA-positive and -negative patients who had no aPLs. Higher miscarriage rates were also reported in ANA-positive patients compared to ANA-negative patients with RPL. The RPL guidelines of the ESHRE state that “ANA testing can be considered for explanatory purposes.” However, there have been a limited number of studies on this issue and sample sizes have been small, and the impact of ANA on the pregnancy prognosis is unclear.

Study design, size, duration
An observational cohort study was conducted at Nagoya City University Hospital between 2006 and 2019. The study included 1,108 patients with a history of 2 or more pregnancy losses.

Participants/materials, setting, methods
4D-Ultrasound, hysterosalpingography, chromosome analysis for both partners, aPLs and blood tests for ANA and diabetes mellitus were performed before a subsequent pregnancy. ANAs were measured by indirect immunofluorescence. The cutoff dilution used was 1:40. In addition, patients were classified according to the ANA pattern on immunofluorescence staining. Live birth rates were compared between ANA-positive and ANA-negative patients after excluding patients with antiphospholipid syndrome, an abnormal chromosome in either partner and a uterine anomaly.

Main results and the role of chance
The 994 patients were analyzed after excluding 40 with a uterine anomaly, 43 with a chromosome abnormality in either partner and 32 with APS. The rate of ANA-positive patients was 39.2 % (390/994) when the 1: 40 dilution result was positive. With a 1:160 dilution, the rate of ANA-positive patients was 3.62 % (36/994). The live birth rate was calculated for 798 patients, excluding 196 patients with unexplained RPL who had been treated with any medication.

With the use of the 1
40 dilution, the subsequent live birth rates were 71.34 % (219/307) for the ANA-positive group and 70.67 % (347/491) for the ANA-negative group (OR, 95%CI; 0.968, 0.707-1.326). After excluding miscarriages with embryonic aneuploidy, chemical pregnancies and ectopic pregnancies, live birth rates were 92.41 % (219/237) for the ANA-positive group and 92.04 % (347/377) for the ANA-negative group (0.951, 0.517-1.747).
Using the 1:160 dilution, the subsequent live birth rates were 84.62 % (22/26) for the ANA-positive group, and 70.47 % (544/772) for the ANA-negative group (0.434, 0.148-1.273).
Subgroup analyses were performed for each pattern on immunofluorescence staining, but there was no significant difference in the live birth rate between the two groups.

Limitations, reasons for caution
The effectiveness of immunotherapies could not be evaluated. However, the results of this study suggest that it is not necessary.

Wider implications of the findings
The measurement of ANA might not be necessary for the screening of patients with RPL who have no features of collagen disease.

Trial registration number
not applicable