Autoimmune disorders are 5 times more common among women, and incidence tends to peak during reproductive years. Thus, these disorders commonly occur in pregnant women.
Systemic Lupus Erythematosus in Pregnancy
Systemic lupus erythematosus (SLE) 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 may later be 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 blood pressure and renal function are normal.
Complications may include (1)
Preterm delivery due to preeclampsia
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.
Antiphospholipid Syndrome in Pregnancy
Antiphospholipid syndrome (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.
Diagnosis
Measurement of circulating antiphospholipid antibodies
Clinical criteria
Antiphospholipid syndrome is suspected in women with a history of any of the following:
≥ 3 unexplained embryonic losses (before 10 weeks gestation) or ≥ 1 unexplained fetal losses (after 10 weeks)
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):
≥ 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
Diagnosis reference
1. Miyakis S, Lockshin MD, Atsumi T, et al: International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost 4(2):295-306, 2006. doi:10.1111/j.1538-7836.2006.01753.x
Treatment
Patients should be monitored closely and referred to a maternal-fetal medicine specialist as needed.
Immune Thrombocytopenia in Pregnancy
Immune thrombocytopenia (ITP), mediated by maternal antiplatelet IgG, tends to worsen during pregnancy and increases risk of maternal morbidity. ITP is characterized by isolated thrombocytopenia in the absence of other etiologies, making it a diagnosis of exclusion.
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 recommended only when
Cesarean delivery is required and maternal platelet counts are < 50,000/microL (1).
Vaginal delivery is expected and maternal platelet counts are < 30,000/microL (2).
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 (3, 4, 5).
Rheumatoid Arthritis in Pregnancy
Rheumatoid arthritis (RA) may begin during pregnancy or, even more often, during the postpartum period. Preexisting RA generally abates temporarily during pregnancy. The fetus is not directly affected, but delivery may be difficult if the woman’s hip joints or lumbar spine is affected. Cesarean delivery is significantly more common in women who have moderate or high disease activity in pregnancy compared to those with low disease activity. Furthermore, a postpartum flare can impair the ability of women with rheumatoid arthritis to take care of themselves and their infant.
1).
Myasthenia Gravis in Pregnancy
Myasthenia gravis varies in its course during pregnancy and even between pregnancies in the same woman. The diagnosis is made after clinical and physical examination reveals muscle weakness and is confirmed by serum immunoassays of autoantibody levels.
During labor, women may need assisted ventilation and are extremely sensitive to medications that depress respiration (eg, sedatives, opioids, magnesium sulfate). Therefore, regional anesthesia is preferred to intravenous medications for pain control during labor and delivery. Because the IgG responsible for myasthenia crosses the placenta, transient myasthenia occurs in 20% of neonates (1), even more if mothers have not had a thymectomy. Although vaginal delivery is recommended, an assisted vaginal delivery may be required due to weakness of striated muscle.
