Background/Purpose: To describe the clinical characteristics of maternal autoimmune-mediated fetal congenital heart block (CHB) in a cohort of pregnant women from an Autoimmune Diseases Pregnancy Clinic. 

Methods: Retrospective observational study of all women presenting with CHB in our Autoimmune Diseases Pregnancy Clinic from January 1997 to December 2012. In addition, outcome of live newborn with CHB is also described. 

Results: Thirteen patients accounting for 17 episodes of CHB were identified. One patient had three episodes and two patients had two episodes each one. The mean (SD) age was 31.3 (5.3) years. Six (46.2%) patients had Sjögren’s syndrome and the remaining 7 (53.8%) were asymptomatic carriers of auto-antibodies. All patients had anti-Ro antibodies and 10/12 (83.3%) had anti-La antibodies. Anti-Ro52 antibody was positive in the 4 women in which it was performed. The mean gestational age at the time of CHB was 21.8 (2.9) weeks (range 18-28). Complete cardiac block (CCB) was detected in 12 (70.6%) fetuses and second-degree CHB in 5 (29.4%). During pregnancy, 4 of them progressed to CCB whereas the remaining changed to first-degree CHB. Severe complications were detected in 5 fetuses (3 hydrops fetalis, 2 fetal growth restriction). Regarding the maternal treatment at diagnosis, only 2 were receiving low-dose corticosteroids, associated with hidroycloroquine and azathioprine in each one, respectively. 

Six cases of CHB were treated with dexamethasone, two with ritodrine and one with the association of dexamethasone, ritodrine and terbutaline. Despite the pharmacological intervention, pregnancy was interrupted in 9 (52.9%) cases. Finally, there were 8 newborns (7 males [87.5%]) with mean age at delivery of 37.2 (1.5) weeks (range 34.5-39).

Elective cesarean was the preferred technique of delivery in all cases. Seven out of 8 (87.5%) newborns were diagnosed of symmetric intrauterine growth restriction. In two cases, Apgar test at first minute was less than 7, because of severe oligohydramnios and meconium aspiration syndrome. Apgar test at 5 and 10 minutes was 9 in all cases.

All newborns were diagnosed of CCB, except one who had first-degree CHB. Half of newborns needed temporal endovascular pacemaker within the 24 hours of life. Two cases showed heart failure signs. A definitive epicardial pacemaker was placed in all cases within 2 weeks of life. Of the remaining patients without a neonatal pacemaker requirement, two needed a pacemaker due to chronotropic and electric insufficiency, at 4 and 14 years old, respectively. Two patients didn’t need a pacemaker due to a good ventricular rate without symptoms and first-degree CHB. One case of CCB with a pacemaker died due to congestive cardiac insufficiency related to a dilated cardiomyopathy (4 months old). Currently, mean age of the 7 living patients is 7 years (range 2-16).

Four women with previous CHB received intravenous immunoglobulins in a subsequent pregnancy being ineffective in two of them. 

Conclusion: CHB is a severe complication related to anti-Ro/La antibodies. Therapy is ineffective and most of the surviving patients will require neonatal pacemaker.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/congenital-heart-block-related-with-maternal-autoimmune-diseases-descriptive-analysis-of-a-series-of-17-cases/