Antiphospholipid syndrome (APS) is an autoimmune disorder that can harm pregnancy by increasing the risk of blood clots and decreasing circulation to the fetus. 70% of individuals with APS are female, and it is fairly common to be found among women of reproductive age.

Antiphospholipid antibodies have a regulatory role in blood coagulation and other physiologic systems. Antiphospholipid antibodies have been associated with a variety of medical problems, including thrombosis, miscarriage, and stroke. In addition to fetal loss, other obstetric complications can occur including preeclampsia, intrauterine growth restriction and preterm delivery.

The three antiphospholipid antibodies that contribute to APS are lupus anticoagulant (LA), anticardiolipin (ACA) and anti-beta glycoprotein1 (AGP). Lupus anticoagulant is present in many individuals without lupus and is associated with thrombosis.

The most common complications associated with APS are due to thrombosis. The risk of thrombosis is significantly increased in pregnancy or the post-partum period. A large proportion of pregnancy losses related to APS occur in the fetal period. Most studies report positive test results for antiphospholipid antibodies in 5-20% of women with frequent miscarriages. Preeclampsia is associated with APS. Although 11-17% of women with preeclampsia will test positive for APS, the association is strongest in women with severe preeclampsia at less than 34 weeks of gestation. Intrauterine growth restriction (IUGR) complicates pregnancies of women with APS 15-30% of the time.

Testing is available for APS, but it is controversial as far as who should be tested. The general criteria for testing are: 1. A previous thrombosis, or 2. Pregnancy morbidity including a) one or more deaths of a fetus beyond 10 weeks of gestation, b) one or more births before 34 weeks due to preeclampsia or placental insufficiency, or c) three or more consecutive pregnancy losses before the 10^th week of gestation.

The goals of treatment for APS during pregnancy are to improve maternal and fetal outcome. For people who have already had a thrombotic event, most experts advise prophylactic heparin (or Lovenox) throughout pregnancy and for six weeks postpartum. Low dose aspirin is also used. Treating women with APS who have not had a previous thrombosis has not been as well studied, but similar treatment may be used.

Long term risks of APS include thrombosis and stroke. In studies of women with APS one half developed thrombosis during the following 3-10 years and 10% developed lupus. Pregnancy and estrogen-containing birth control pills appear to increase the risk of thrombosis. Experts agree that women who have APS should not use any birth control pills that contain estrogen, but progesterone-only forms of birth control should be safe.

Reference: The American Congress of Obstetricians and Gynecologists Practice Bulletin.