Autoimmune Hepatitis and Pregnancy

Etiology

The probable theory for the pathogenesis of autoimmune hepatitis – in pregnant women and the general population – is that the disease results from an environmental trigger in a genetically predisposed individual. The precise mechanism between the genes and the autoimmune process is still unknown. However, at the molecular level, they are believed to involve an antigen, a major histocompatibility complex (MHC), and a T cell receptor, which together form a complex in which complementary-determining regions identify and contact the antigen-MHC complex.[9] The suggested environmental triggers that lead to this T cell-mediated immune response targeting the liver include viruses, medications, herbal supplements, and even immunizations.[10] However, in most cases, the particular inducer of autoimmunity is never identified.

Epidemiology

In the general population, autoimmune hepatitis has a low incidence (1 per 100000).[2] The disease more commonly affects women and manifests at childbearing age, but the first episode of AIH can occur at any age.[1][3] For type 1 AIH, the female to male ratio is 4 to 1, but for type 2 AIH, the ratio is 10 to 1.[11][12]

Pathophysiology

The pathology of autoimmune hepatitis is a gradual hepatocellular inflammation that cannot be explained by the common etiologies of chronic liver disease, such as alcohol-related liver disease, viral hepatitis, and exposure to hepatotoxic substances, and hereditary liver disorders.[1] The natural history of the disease may progress from acute hepatitis to chronic liver disease and, ultimately, to cirrhosis. The probable mechanism of obstetric complications in women with AIH is the targeted involvement of maternal-fetal interface structures by autoantibodies and natural immune cells activated by the disease.[4] These interface structures that get targeted include cellular components of intervillous space, endothelial tissue of spiral veins, and superficial epithelial cells of the decidua. This process leads to an increased risk of first-trimester miscarriage and preterm delivery.[4][13][1] Thrombosis is another complication that occurs due to endothelial damage and complement system activation, leading to worse perinatal outcomes.

Histopathology

Histopathology showing the following typical features can confirm the diagnosis of autoimmune hepatitis:

• The presence of interface hepatitis
• Lymphocytic infiltration of the portal tracts and extending into the lobule
• Emperipolesis, or active penetration of one cell into and through a large cell
• Hepatic rosette formation

History and Physical

The clinical presentation of autoimmune hepatitis can be highly variable. It can present as either an acute or chronic illness with a fluctuating pattern. It can also be discovered incidentally in completely asymptomatic individuals on routine laboratory testing such as those required for insurance, for employment, or before blood donation.[14][15] Patients can present with debilitating symptoms such as malaise, anorexia, fatigue, and weight loss. The patients can also present with acute liver failure as an initial presentation with jaundice, ascites, and coagulopathy.[16][17][18]

In both pregnant women and the general population, physical findings expected of AIH range from a normal physical examination to findings suggestive of cirrhosis or liver failure (e.g., jaundice, ascites, splenomegaly).

Also, individuals with AIH may present with a coexisting extrahepatic disorder, which may also be autoimmune-mediated. The common autoimmune disorders associated with AIH include autoimmune thyroiditis, rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, celiac disease, and ulcerative colitis.[19][20]

Evaluation

The diagnosis of autoimmune hepatitis is similar in both pregnant women and the general population. It has its basis in representative serologic and histologic findings as well as the exclusion of other types of chronic liver disease.[2] Often, the disease can be strongly suspected based on clinical and laboratory features. Thus, a liver biopsy is not always necessary in patients with characteristic findings on non-invasive testing.[21]

For individuals with consistent clinical or laboratory features, it is recommended to obtain serum anti-nuclear (ANA), anti-smooth muscle (ASMA), anti-mitochondrial (AMA), and anti-liver/kidney microsomal-1 (ALKM-1) antibodies, as well as either an immunoglobulin G (IgG) or gamma globulin level. It is recommended for those who are negative for these autoantibodies to obtain anti-soluble liver antigen/liver pancreas antibody, anti-actin antibodies, and atypical perinuclear antineutrophil cytoplasmic (p-ANCA) antibodies. 

Patients with AIH historically categorize into two disease subtypes according to the nature of autoantibodies [2]: 

• Type 1 AIH: Anti-nuclear (ANA) and/or anti-smooth muscle (ASMA) antibodies with F-actin specificity
• Type 2 AIH: Anti-liver/kidney microsomal antibody type 1 (ALKM-1) and/or anti-liver cytosol antibody type 1 (ALC-1)

Roughly 20 percent of individuals presenting with AIH features lack circulating ANA, ASMA, or ALKM-1 antibodies.[11] These individuals usually present as having autoantibody-negative autoimmune hepatitis. Often, the only indication that AIH is the underlying disease is a therapeutic response to anti-inflammatory therapy.

In specific instances, it may be preferable to obtain a liver biopsy in individuals in whom autoimmune hepatitis is suspected because histologic assessment can confirm the diagnosis and help to guide treatment. Histologic evaluation is especially useful as part of the diagnostic evaluation for those with few or atypical findings, negative autoantibodies, and/or normal IgG levels. 

After obtaining a liver biopsy, the diagnostic confirmation is by histology showing typical features (see histopathology section).

Treatment / Management

The course of autoimmune hepatitis during pregnancy is unpredictable. Though the literature is limited, up to 20% of patients with AIH will flare during pregnancy, which is associated with a high rate of fetal and maternal complications.[3][22] Thus, women with AIH should be counseled to delay pregnancy at least one year until their disease is under optimal control.[3](B3)

Medical Treatment

The preferred treatment for AIH during pregnancy include glucocorticoids at the lowest possible doses, alone or in combination with azathioprine.[22] Azathioprine is a U.S. FDA pregnancy category D medication, and providers should prescribe it only if the benefit justifies the potential risks to the fetus. Meanwhile, prednisone is a U.S. FDA pregnancy category C medication and does not extensively cross the placenta, is not associated with teratogenicity in humans, and is the preferred treatment for control of disease activity during pregnancy in women with AIH. Though the studies are limited, azathioprine and prednisone use in pregnant women with AIH did not increase the risk of adverse fetal and maternal outcomes, so optimal AIH control outweighs the risks associated with these medications.[3] Thus, treatment should continue, and the patient monitored closely for flares. Other medications used to treat AIH, including mycophenolate mofetil (MMF) and tacrolimus, are contraindicated in pregnancy because they cause congenital malformations/congenital disabilities, premature birth, low birth weight, and severe infections in the expectant mother.[3][23](B3)

AIH Treatment and Breastfeeding

Breastfeeding is also safe with prednisone. Azathioprine is excreted at low levels in breast milk, and most experts recommend continuing azathioprine use during breastfeeding despite manufacturers’ recommendations against using them during lactation.[3] There are no data on budesonide and mycophenolate, and breastfeeding.

Management of AIH Flare

During flares, the management of pregnant patients with AIH should be similar to non-pregnant patients, with higher doses of prednisone and/or the addition of azathioprine.

Patients with Cirrhosis and AIH

Cirrhosis can occur as an initial presentation at the time of AIH diagnosis in up to 40% of patients. Therefore, providers will not infrequently encounter pregnant females with cirrhosis secondary to AIH.[3][23] Pregnancy in compensated cirrhotic women is no longer feared, nor is it contraindicated, but it correlates with increased preeclampsia rates, low birth weight, preterm delivery, and neonatal death with increased risk of maternal mortality and complications.[24][25] In contrast, patients with a MELD (Model for End-Stage Liver Disease) score of greater than 10 are at higher risk for poor maternal and fetal outcomes, with an increased risk of decompensation and maternal mortality of up to 7.8%.[24] This group of patients should have thorough discussions with their obstetrician and hepatologist regarding elective pregnancy termination, surrogate pregnancy, and delaying pregnancy until after liver transplantation.[23]

During pregnancy, compensatory dilation of collateral veins that join the portal circulation and the azygos vein occurs, causing expansion of the circulating blood volume and extrinsic compression of the inferior vena cava by the pregnant uterus, leading to increased portal hypertension and variceal bleeding, especially during the third trimester and labor and delivery.[23] This situation is the most common complication and cause of maternal morbidity and mortality. Thus, all patients should have an upper endoscopy to identify and potential prophylactic endoscopic variceal ligation of high-risk varices – especially around 28 weeks of gestation when maximum volume expansion occurs.[3] Management of other portal hypertension complications, such as hepatic encephalopathy and ascites, should be per the guidelines established for the general population.

Postpartum Care

AIH may flare with the return of normal immunity after delivery, and, in fact, flares are twice as frequent in the postpartum period during pregnancy.[3][23] The reported incidence of flares is around 20% to 50% of patients postpartum. Therefore, recommendations are that the patient should be followed by a hepatologist closely. The patient's liver function tests and immunoglobulin G (IgG) level should be monitored at delivery and then at 4-to-6 week intervals during the first three months postpartum.[3]

Differential Diagnosis

Autoimmune hepatitis has an array of clinical phenotypes. For this reason, it appears in the differential diagnosis for patients presenting with abnormal liver biochemical tests, cirrhosis, acute hepatitis, or acute liver failure[26]. Furthermore, even with the establishment of diagnostic criteria, there are still issues to be clarified attributable to its variability, such as autoantibody-negative AIH, drug-induced AIH, AIH sharing features with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC) (i.e., overlap syndrome), and also rarely, post-transplant de novo AIH.

Prognosis

Pregnancy in patients with autoimmune hepatitis is associated with an increased risk of fetal complications and maternal complications.[3] However, data shows that the number of pregnancies reported in women with AIH is becoming more frequent due to better clinical management and high-quality prenatal and antenatal care. Currently, pregnancy and childbirth in AIH appear to be safe for both mother and child.[8]

Complications

Pregnant women with AIH should be counseled against pregnancy in the context of cirrhosis (MELD score greater than 10), primarily due to the risk of gastroesophageal variceal bleed, although ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, and hepatorenal syndrome.[27]