Four years ago, I miscarried at 12 weeks. I sat in my OB's office insisting this loss wasn't nature's way of handling an unviable arrangement of chromosomes. Citing my nagging intuition, I asked to be tested for autoimmune disorders, which I'd read could cause miscarriage. My OB kindly and patiently convinced me doing the necessary blood work would waste time and money. She saw no evidence to indicate that my miscarriage was anything out of the ordinary.

But the evidence showed up in spades when I got pregnant again several months later; my routine syphilis test came back positive. A more sophisticated blood panel confirmed the obvious: I did not have a venereal disease. What I did have, however, were unusually high levels of antinuclear antibodies, which can cause a false positive syphilis result. After I underwent more lab work, I learned I had Antiphospholipid Antibody Syndrome (APS), an obscure, enigmatic autoimmune condition that more often affects women, many of whom don't even know they have it until their pregnancies go awry. Only 8 weeks along, I was classified as a high-risk obstetric patient and began anticoagulant therapy to keep from miscarrying again.

What is Antiphospholipid Antibody Syndrome?
So what is this little-known culprit with a fancy name? In simplest terms, APS is an autoimmune disorder in which the body doesn't recognize parts of its own cells and creates antibodies to attack them. According to Dr. Victoria A. Seligman, a rheumatology fellow at the University of California, San Francisco, APS is diagnosed when a patient has one or more of the following criteria:

1. Positive antibodies test (includes lupus anticoagulant antibody, anticardiolipin antibody, and false positive syphilis screen) on two separate occasions, at least 8 weeks apart;
2. Recurrent fetal loss
3. Low platelet count
4. Clotting events

Seligman stresses that not every woman who tests positive for the antibodies has APS. An estimated 2 to 5 percent of women have elevated antibody levels, but only 10 to 20 percent of this group have problems in pregnancy. For those in the high-risk category, possible pregnancy risks include:

1. Miscarriage
2. Clotting events, also postpartum
3. Prematurity and intrauterine growth retardation (IUGR)
4. Pre-eclampsia

Anticoagulant Therapy During Pregnancy
When a woman with undiagnosed, untreated APS gets pregnant, her body may begin to reject the fetus. Antibodies form tiny blood clots that enter the placenta and shut off the supply of oxygen and nutrients to the baby, resulting in miscarriage. Although doctors used to wait to diagnose APS until a woman had three consecutive pregnancy losses, many OBs now try to prevent this needless suffering by testing a patient after one or two losses.

Roberta Montgomery of Los Angeles had a normal pregnancy with her son, Roland, now 2 years old. But her second pregnancy ended at 11 weeks after a previous ultrasound had shown a healthy fetal heartbeat. Thinking this an unusual development, Roberta's astute OB checked her for APS and found she had moderate levels of antiphospholipid antibodies. Because Roberta wanted to get pregnant again, her OB sent her to Dr. Hal Danzer, a Beverly Hills fertility specialist. Dr. Danzer prescribed two blood thinners -- baby aspirin and heparin -- to prevent clots. Both medications are considered safe during pregnancy and heparin has proven extremely beneficial in combating miscarriage and intrauterine growth retardation.

Under Danzer's supervision, Roberta learned to give herself heparin shots in the stomach twice a day while she was trying to conceive to facilitate implantation. When she got pregnant -- fortunately, after just a couple of months -- she maintained the heparin therapy until the end of her second trimester. Her placenta and amniotic fluid were in good condition and the fetus was growing normally -- all signs that the heparin was indeed keeping clots from forming. With Danzer's permission, Roberta stopped the heparin shots at the beginning of her third trimester and continued taking a daily baby aspirin for the duration of her pregnancy. Although he arrived 2 weeks early, Roberta's second son Bobby, now 5 months, weighed in at a strapping 8 pounds, 11 ounces.

Not every woman with APS needs to take heparin during pregnancy. After miscarrying at 16 weeks, Kathy Hennessy of Greenville, South Carolina learned she had low levels of antiphospholipid antibodies. Because her condition was borderline, she required only baby aspirin during her second pregnancy.

Daughter Emma Gwynne, now 17 months, was born safely one week late weighing 9 pounds, 7 ounces.