Maternal Autoimmune Disorder Diagnosed by Fetal Complete Heart Block with Postnatally Diagnosed Down Syndrome

Author Information

Shilotri M*, More V**,  Satia MN***
(** Second year resident, **Assistant Professor, *** Professor, Department of Obstetrics and Gynecology, Seth G. S. Medical College and KEM HospitalMumbaiIndia.)


Congenital complete atrioventricular block may result from a congenital cardiac anomaly or the presence of anti-Ro and/or anti-La antibodies in women who have systemic lupus erythematosus, Sjogren’s syndrome, undifferentiated autoimmune disorder, or are asymptomatic. The prognosis of the baby depends on the time of diagnosis and presence of a cardiac anomaly. Down syndrome has a high incidence of congenital cardiac anomalies, however, complete atrioventricular block is rarely seen. We present a case of a 23 year old gravida 2, para 1, living 1 who was asymptomatic and was diagnosed to have autoimmune antibodies on evaluation for fetal bradycardia which was later diagnosed as complete heart block on fetal echocardiography. The neonate was later incidentally diagnosed to have Down syndrome with atrial septal defect.


Congenital complete atrioventricular block is a rare disorder with an incidence of 1 in 22,000 live births.[1] Congenital cardiac anomalies are seen in 44% of Down syndrome cases.[2] Amongst cases of Down syndrome, varying degrees of heart block are seen with atrioventricular septal defects while atrial septal defect is only associated with PR interval prolongation on ECG.[3] Congenital complete atrioventricular block may be diagnosed antenatally as early as 16 weeks gestation. It has a high perinatal morbidity and mortality. Women with positive anti-Ro and/or anti-La antibodies should be monitored with serial fetal echocardiography to detect early any congenital conduction defects. Although there are no guidelines for antenatal treatment of fetal heart block, there are many promising therapies being studied.

Case Report

A 23 year old gravida 2 para 1, living 1 registered antenatally at our clinic at 23.5 weeks gestation. She had no history of any significant medical or surgical illness. She had a previous full term normal delivery and the child was well. At 28.5 weeks gestation the fetal heart sounds were found to be irregular ranging from 60 beats/ minute to 120 beats/ minute, as heard on a stethoscope and confirmed on a hand-held Doppler device during a routine antenatal examination. She was advised admission for evaluation of possible fetal cardiac anomaly. However she was not willing for the same. An obstetric ultrasonography for fetal anomalies and a fetal echocardiography was advised. At her next antenatal visit at 31.5 weeks, the baseline fetal heart rate was 50 beats/ minute. Ultrasonography for fetal malformations at 29 weeks showed evidence of fetal bradycardia (53 beats per minute) most probably due to conduction defect with a complete heart block, mild pericardial effusion and reverse flow in ductus venosus suggestive of early fetal hydrops. No other anomalies were evident. As she was not willing for admission, she was advised to do blood investigations such as anti-nuclear (ANA) antibodies, anti-double stranded DNA (dsDNA) antibodies, anti-Ro (SSA), anti-La (SSB) antibodies and blood sugars. She was advised to follow up with the reports in the outdoor patient department. Patient later returned to the hospital in active labor at 37.1 weeks and delivered uneventfully. She delivered a female child of 1.672 kg with an Apgar score of 8/10. On examination of the neonate, Mongoloid features were observed (slanting eyes, low set ears and depressed nasal bridge) with clinodactyly and bradycardia. Baby was immediately shifted to the neonatal intensive care unit for further evaluation. ECG of the neonate was suggestive of complete heart block with atrial rate of 160 beats/ minute and ventricular rate of 60 beats/ minute. Echocardiography showed a 3 mm atrial septal defect of ostium secundum type. No other cardiac anomalies were detected. Cardiology opinion was taken who advised monthly follow up of the baby. The neonate’s blood counts, hepatic and renal function tests were within normal limits. Karyotype and thyroid function tests of the baby were sent in view of the Mongoloid features. The baby was discharged on full feeds and advised to follow up with the above reports and was diagnosed to have Down syndrome on karyotyping. On maternal evaluation, the patient tested positive for ANA , anti-Ro and anti-La antibodies and was negative for anti-dsDNA antibodies. Rheumatology opinion was sought and was advised urine routine examination and complement levels (C3, C4) which were normal. CRP levels  were raised and thyroid function tests were suggestive of hypothyroidism. Her complete blood counts, renal and liver function tests and blood sugars were normal. She had no complaints of rash, photosensitivity, arthritis or long standing fever. She was asked to follow up in the rheumatology outpatient department for further evaluation of type of autoimmune disorder. Thus, the patient was diagnosed to have an autoimmune disorder on evaluation for the fetal heart block.


Congenital complete atrioventricular heart block may manifest any time from 16 weeks gestation to young adulthood. In the antenatal period it may first be detected as bradycardia on auscultation during an obstetric examination, as in our case, or on a routine obstetric ultrasonography. Fetal congenital heart block may be a result of an underlying cardiac structural anomaly as seen in 30 – 53% of cases.[1] The most common cardiac anomaly associated with heart block is left atrial isomerism with or without atrioventricular septal defect and levo-transposition of great arteries.[4] In a structurally normal heart, congenital heart block in the form of neonatal lupus is a result of maternal autoantibodies to intracellular ribonucleoprotiens {anti-Ro (SS-A) and/ or anti-La (SS-B)}, detected on enzyme linked immunosorbent assay. Women that test positive for anti-Ro antibodies have a 3% risk of bearing a child with neonatal lupus.[2] At the time of diagnosis of the fetal heart block the mother may be a known case of systemic lupus erythematosus (26%), Sjogren’s disease (14%), an undifferentiated autoimmune disorder (19%) or may be completely asymptomatic (40%).[3] It is postulated that these autoantibodies are passively transferred through placental circulation which in turn injure a formerly normal fetal heart. The heart block varies from first to third degree and the antibody mediated injury may result in a late cardiomyopathy as seen in 5-11% of cases.[4] Neonatal lupus has other manifestations such as an annular, photosensitive rash on the face, low counts of red blood cells, white blood cells, platelets and deranged liver function tests. These manifestations usually resolve spontaneously, however, the cardiac changes are permanent.
Down syndrome is associated with atrioventricular septal defects (30%), atrial septal defect (25%), ventricular septal defect (22%), patent ductus arteriosus (5%), coarctation of aorta (5%) and tetralogy of Fallot (3%).[2] The type of conduction disorder seen in Down syndrome depends upon the cardiac anomaly. Varying degrees of heart block are seen with atrioventricular septal defects while atrial septal defect is only associated with PR interval prolongation on ECG. Isolated complete congenital heart block in a case of Down syndrome is rare.[7] Thus, in our case, the fetal complete heart block was most likely caused by the maternal autoimmune antibodies.
On diagnosis of congenital heart block, the fetus is monitored by serial echocardiograms. Several antenatal therapies for neonatal lupus have been attempted such as dexamethasone therapy, plasmapheresis, beta stimulation by salbutamol, hydroxychloroquine, intravenous immunoglobulins etc.[8] However, no therapy has been approved as standard protocol for antenatal management of neonatal lupus. In neonates and children cardiac pacing may be required if they are symptomatic, have congestive cardiac failure or in asymptomatic neonates with awake baseline heart rate of less than 55/min.[1] As the neonate in our case had a baseline heart rate of 60/minute and was asymptomatic, pacing was not done.
Complete heart block predisposes the baby to cardiac failure, hydrops fetalis, fetal or neonatal death. Prognosis depends on the presence of an underlying cardiac structural abnormality with a survival beyond the neonatal period of only 14% as compared to 85% in autoimmune congenital heart block.[1] Prognosis is also determined by the time of diagnosis of the disease, with those diagnosed in the newborn period having a better fate than those that are detected in-utero as it is thought that those with severe disease perish in-utero and those with a milder disease survive for a longer time. Although women who test positive for anti-Ro and/or anti-La antibodies may be asymptomatic at the time of diagnosis, there are reports of them becoming symptomatic a few years after the affected delivery, the median time being 1.5 years.[3] Thus it is worthwhile to advise these patients to follow up with a rheumatologist.

  1. Kertesz NJ, Fenrich AL, Friedman RA. Congenital complete atrioventricular block. Tex Heart Inst J. 1997;24(4):301-307.
  2. Stoll C, Dott B, Alembik Y, Roth MP. Associated congenital anomalies among cases with Down syndrome. Eur J Med Genet. 2015 Dec;58(12):674-80.
  3. Clark EB, Kugler JD. Preoperative secundum atrial septal defect with coexisting sinus node and atrioventricular node dysfunction. Circulation. 1982;65(5):976-80. PubMed PMID: 7074763
  4. Friedman DM, Duncanson LJ, Glickstein J, Buyon JP. A review of congenital heart block. Images Paediatr Cardiol. 2003;5(3):36-48.
  5. Waltuck J, Buyon JP. Autoantibody-associated congenital heart block: outcome in mothers and children. Ann Intern Med 1994;120:544-51.
  6. Moak JP, Barron KS, Hougen TJ, Wiles HB, Balaji S, Sreeram N, et al. Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela. J Am Coll Cardiol. 2001;37(1): 238–242. [PubMed: 11153745]
  7. Machakanur V. Congenital Complete Heart Block in Down Syndrome: A Rare Case Report. Journal of Evolution of Medical and Dental Sciences. 2015; 47(4): 8254-8257, DOI: 10.14260/jemds/2015/1197
  8. Hunter LE, Simpson JM. Atrioventricular block during fetal life. J Saudi Heart Assoc. 2015; 27(3): 164-178. doi:10.1016/j.jsha.2014.07.001

Shilotri M, More V, Satia MN. Maternal Autoimmune Disorder diagnosed by Fetal Heart Block. JPGO 2016. Volume 3 No. 3. Available from: