Congenital Heart Block Due To Maternal Autoantibodies

Author Information
Khadkikar Rashmi*, Prasad Madhva**,  Jain Neha**, Chauhan AR***
(* Assistant Professor, ** Resident, ***, Additional Professor. Department of Obstetrics and Gynecology, Seth G.S. Medical College and K.E.M Hospital, Mumbai, India.)


Congenital heart block (CHB) is associated with maternal antibodies to Ro (SSA) and La (SSB) that cross the placenta and damage the AV node of fetus. An asymptomatic 27-year-old primigravida, diagnosed with second degree fetal heart block was investigated and found positive for antinuclear antibodies (ANA), anti-Ro and anti-La antibodies.  Fetal echocardiography (2D-echo) showed no structural defect but bradycardia. The patient was started on dexamethasone 8mg/day. She had preterm premature rupture of membranes (PPROM) at 34 weeks and underwent emergency cesarean section (LSCS). The baby was born with complete heart block but was managed conservatively in view of low birth weight. The infant is now 5 months old and permanent pacemaker implantation is planned.


The occurrence rate of CHB is approximately 2 to 3% of all pregnancies born to women with autoantibodies. The recurrence rate with a previous affected child is 18 to 20%.[1] CHB is most commonly diagnosed between 18 and 24 weeks of gestation, and may be first, second or third degree (complete). In pregnant women with autoimmune conditions, maternal autoantibodies cross the placenta and cause inflammation and fibrosis of AV node, causing block in signal conduction leading to congenital heart block. However, though the fetus is affected due to maternal anti-Ro/SSA and anti-La/SSB antibodies, the mother herself may be asymptomatic.

Case report

A 27 year old primigravida was referred at 28 weeks’ gestation in view of fetal bradycardia (fetal heart rate [FHR] of 78 beats/ min) and 2D-echo showing second degree heart block (intermittent type II) with early diastolic dysfunction, without evidence of hydrops fetalis. Detailed malformation scan was normal, liquor was adequate and there was no placental abnormality. She had no clinical features of autoimmune disorder or any known medical or surgical illness, except hypothyroidism for which she was on thyroid hormone supplementation.
In view of these findings, she was investigated: ANA, Anti-Ro, anti-La antibody tests were positive,   anti-dsDNA was negative. Consultations with a rheumatologist, a neonatologist and a cardiologist were obtained. Maternal therapy was started with tablet Dexamethasone 4 mg and tablet Hydoxychloroquine twice daily which was continued till delivery.
The patient was followed up weekly (FHR on auscultation varied between 60 -70/min) with USG for fetal viability and growth, and fetal 2D-Echo every 15 days. Degree of heart block progressed despite medications, and at 33 weeks there was complete heart block (FHR 50/min). She was counseled regarding need of pacemaker post-delivery.
Patient had premature rupture of membranes at 34 weeks of gestation. In view of impossibility of fetal heart monitoring during labor, emergency LSCS was performed. Male child of 1820 g was born with Apgar of 9/10 and was managed conservatively in neonatal ICU. Post delivery, ECG was suggestive of complete heart block with narrow QRS escape rhythm. Conservative management was continued in view of prematurity and low birth weight. Four months post-delivery, the infant was started on diuretics and was advised permanent pacemaker implantation as ECG showed complete heart block with ventricular rate of 43/min.

Figure 1: Fetal 2D Echocardiography

Figure 2: Postnatal ECG


Neonatal lupus is diagnosed by the presence of bradycardia in a fetus or newborn without structural cardiac abnormalities. Other manifestations of neonatal lupus are skin rashes, liver function abnormalities and cytopenias. These non-cardiac manifestations resolve after maternal antibodies are cleared from circulation (6 to 8 months after birth) but the conduction system disease is irreversible. The mother may have SLE or Sjogren's syndrome or may be asymptomatic, as in our case.[2]
CHB associated with neonatal lupus is a form of passively acquired autoimmune disease in which maternal autoantibodies cross the placenta and injure the previously normal fetal heart. Anti-Ro and anti-La antibodies have direct arrhythmogenic activity; the onset of bradycardia is between 16 and 24 weeks of gestation, corresponding to placental transfer of maternal IgG antibodies. These antibodies bind to fetal cardiocytes and inhibit the normal physiological removal of apoptotic cells, resulting in inflammatory reaction and fibrosis of the conduction system. Though these antibodies are directly involved in the pathogenesis of CHB, environmental, fetal, maternal, and genetic factors also predispose to this condition.[3]
Most patients are diagnosed antenatally with first and second degree heart block which should be managed with steroids and monitored for improvement or worsening to irreversible complete heart block, where steroids may not be effective. Fetal heart rate is a prognostic indicator of the disease; a critical level of less than 55/min, along with myocardial dysfunction and presence of hydrops fetalis (due to increase in ventricular size as an adaptation to persistent bradycardia), are risk factors for high mortality (85%) in neonatal period.[4] 
Fetal 2D echo is recommended in second trimester in mothers affected with autoimmune disorders and those with previous child affected with neonatal lupus. Conversely, presence of autoantibodies in mother should be suspected with fetal congenital heart block in the absence of any cardiac structural abnormality.
No guidelines for treatment of CHB exist though various therapeutic regimens are proposed: β-sympathomimetic drugs to increase the FHR; plasmapheresis and steroids to target the antibody-mediated inflammation; and digoxin or frusemide to prevent hydrops. The use of glucocorticoids in fetal second degree heart block may increase the chances of reverting to first degree heart block rather than progressing to third degree heart block. Dexamethasone may also improve fetal survival in complete heart block. After birth, therapy includes medical management, along with pacing in those infants who do not respond to medical treatment alone.[4]
In conclusion, multidisciplinary team approach by level III sonologist, obstetrician, neonatologist and pediatric cardiologist is valuable in management of this rare condition.


1.      Buyon JP, Heibert R, Copel J, et al. Autoimmune-associated congenital heart block: Mortality, morbidity, and recurrence rates obtained from a national neonatal lupus registry. J Am Coll Cardiol.1998; 31:165.
2.      Tincani A, Rebaioli CB, Taglietti M and Shoenfeld Y. Heart involvement in systemic lupus erythematosus, anti-phospholipid syndrome and neonatal lupus. Rheumatology 2006; 45(suppl 4): iv8-iv13.
3.      Friedman DM, Duncanson LJ, Glickstein J and Buyon JP. A review of congenital heart block. Images Paediatr Cardiol. 2003 Jul- Sep; 5(3): 36-48.
4.      Friedman DM, Rupel A, Glickstein J and Buyon JP. Congenital heart block in neonatal lupus: the pediatric cardiologist's perspective. Indian J Pediatr 2002 Jun; 69(6): 517-22.


Khadkikar R, Prasad M,  Jain N, Chauhan AR. Congenital Heart Block Due To Maternal Autoantibodies. JPGO 2014 Volume 1 Number 5 Available from: