Autoimmune disorders Autoimmune Disorders In autoimmune disorders, the immune system produces antibodies to an endogenous antigen (autoantigen). The following hypersensitivity reactions may be involved: Type II: Antibody-coated cells... read more are 5 times more common among women, and incidence tends to peak during reproductive years. Thus, these disorders commonly occur in pregnant women.
Antiphospholipid Antibody Syndrome in Pregnancy
Antiphospholipid antibody syndrome Antiphospholipid Antibody Syndrome (APS) Antiphospholipid antibody syndrome is an autoimmune disorder in which patients have autoantibodies to phospholipid-bound proteins. Venous or arterial thrombi may occur. The pathophysiology is... read more (APS) is an autoimmune disorder that predisposes patients to thrombosis and, during pregnancy, increases risk of
APS is caused by autoantibodies to certain phospholipid-binding proteins that would otherwise protect against excessive coagulation activation.
Measurement of circulating antiphospholipid antibodies
Antiphospholipid syndrome is suspected in women with a history of any of the following:
≥ 1 unexplained fetal losses or ≥ 3 unexplained embryonic losses
Prior unexplained arterial or venous thromboembolism
New arterial or venous thromboembolism during pregnancy
Antiphospholipid syndrome is diagnosed by measuring levels of circulating antiphospholipid antibodies (anticardiolipin, beta-2 glycoprotein I, lupus anticoagulant) with positive results on ≥ 2 occasions 12 weeks apart.
Diagnosis of antiphospholipid syndrome requires ≥ 1 clinical criterion in addition to ≥ 1 of the laboratory criteria above. Clinical criteria can be vascular (prior unexplained arterial or venous thromboembolism in any tissue) or pregnancy-related. Pregnancy-related criteria include the following:
≥ 1 unexplained deaths of a morphologically normal (via ultrasonography or direct examination) fetus at ≥ 10 weeks gestation
≥ 1 premature births of a morphologically normal neonate at ≤ 34 weeks gestation because of eclampsia or severe preeclampsia or with features of placental insufficiency
≥ 3 unexplained consecutive spontaneous pregnancy losses at ≤ 10 weeks gestation, with maternal anatomic and hormonal abnormalities and paternal and maternal chromosomal causes excluded
Prophylaxis with anticoagulants and low-dose aspirin
Women with antiphospholipid syndrome are usually treated prophylactically with anticoagulants and with low-dose aspirin during pregnancy and for 6 weeks postpartum.
Immune Thrombocytopenia in Pregnancy
Immune thrombocytopenia (ITP) Immune Thrombocytopenia (ITP) Immune thrombocytopenia (ITP) is a bleeding disorder usually without anemia or leukopenia. Typically, it is chronic in adults, but it is usually acute and self-limited in children. Spleen size... read more , mediated by maternal antiplatelet IgG, tends to worsen during pregnancy and increases risk of maternal morbidity.
Corticosteroids reduce IgG levels and cause remission in most women, but improvement is sustained in only 50%. Immunosuppressive therapy and plasma exchange further reduce IgG, increasing platelet counts. Rarely, splenectomy is required for refractory cases; it is best done during the 2nd trimester, when it causes sustained remission in about 80%.
IV immune globulin increases platelet count significantly but briefly, so that labor can be induced in women with low platelet counts. Platelet transfusions are indicated only when
Cesarean delivery is required and maternal platelet counts are < 50,000/microL.
Vaginal delivery is expected and maternal platelet counts are < 10,000/microL.
Although antiplatelet IgG can cross the placenta, it only very rarely causes fetal or neonatal thrombocytopenia. Maternal antiplatelet antibody levels (measured by direct or indirect assay) cannot predict fetal involvement. Risk of neonatal intracranial hemorrhage due to maternal ITP is not affected by the mode of delivery nor by birth trauma. Accordingly, the current accepted practice is vaginal delivery, without routinely determining the fetal platelet count, and cesarean delivery only for obstetric indications.
Myasthenia Gravis in Pregnancy
Myasthenia gravis Myasthenia Gravis Myasthenia gravis is characterized by episodic muscle weakness and easy fatigability caused by autoantibody- and cell-mediated destruction of acetylcholine receptors. It is more common among... read more varies in its course during pregnancy. Frequent acute myasthenic episodes may require increasing doses of anticholinesterase drugs (eg, neostigmine), which may cause symptoms of cholinergic excess (eg, abdominal pain, diarrhea, vomiting, increasing weakness); atropine may then be required. Sometimes myasthenia becomes refractory to standard therapy and requires corticosteroids or immunosuppressants.
During labor, women may need assisted ventilation and are extremely sensitive to drugs that depress respiration (eg, sedatives, opioids, magnesium sulfate). Because the IgG responsible for myasthenia crosses the placenta, transient myasthenia occurs in 20% of neonates, even more if mothers have not had a thymectomy.
Rheumatoid Arthritis in Pregnancy
Rheumatoid arthritis (RA) Rheumatoid Arthritis (RA) Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that primarily involves the joints. RA causes damage mediated by cytokines, chemokines, and metalloproteases. Characteristically... read more may begin during pregnancy or, even more often, during the postpartum period. Preexisting RA generally abates temporarily during pregnancy. The fetus is not specifically affected, but delivery may be difficult if the woman’s hip joints or lumbar spine is affected.
If a woman develops an RA flare during pregnancy, first-line treatment usually begins with prednisone. For refractory cases, other immunosuppressants may be required.
Systemic Lupus Erythematosus in Pregnancy
Systemic lupus erythematosus (SLE) Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic, multisystem, inflammatory disorder of autoimmune etiology, occurring predominantly in young women. Common manifestations may include arthralgias and... read more may first appear during pregnancy; women who have had an unexplained 2nd-trimester stillbirth, a fetus with growth restriction, preterm delivery, or recurrent spontaneous abortions are often later diagnosed with SLE.
The course of preexisting SLE during pregnancy cannot be predicted, but SLE may worsen, particularly immediately postpartum. Outcomes are better if conception can be delayed until the disorder has been inactive for at least 6 months, the drug regimen has been adjusted in advance, and BP and renal function are normal.
Complications may include
Congenital heart block due to maternal antibodies that cross the placenta
Significant preexisting renal or cardiac complications increase risk of maternal morbidity and mortality. Diffuse nephritis, hypertension, or the presence of circulating antiphospholipid antibodies (usually anticardiolipin antibody or lupus anticoagulant) increases risk of perinatal mortality. Neonates may have anemia, thrombocytopenia, or leukopenia; these disorders tend to resolve during the first weeks after birth when maternal antibodies disappear.
If hydroxychloroquine was used before conception, it may be continued throughout pregnancy. SLE flares are usually treated with low-dose prednisone, IV pulse methylprednisolone, hydroxychloroquine, and/or azathioprine. High-dose prednisone and cyclophosphamide increase obstetric risks and are thus reserved for severe lupus complications.