Background/Purpose: Multiple factors, including proteinuria, antiphospholipid syndrome, thrombocytopenia and hypertension, are predictive of pregnancy loss in SLE. In the PROMISSE study of mediators of pregnancy loss, only a battery of lupus anticoagulant tests (Dil PT, dRVVT, PTT LA, and KCT) were predictive of adverse pregnancy outcomes (including pregnancy loss, preterm birth, pre-eclampsia, and small for gestational age). We examined the predictive value of one baseline lupus anticoagulant test (dRVVT) with pregnancy loss alone in women with SLE.

Methods: This analysis is based on pregnancies that were observed from 1987 to 2011.  After excluding twin pregnancies, there were 402 pregnancies from 326 different women.  We determined the percentage of women who had a pregnancy loss in groups defined by potential risk factors.  Generalized Estimating Equations were used to calculate p-values, accounting for repeated pregnancies of the same woman.

Results:

The age at pregnancy was <20 years (3%), 20-29 (50%), 30-39 (43%), and over 40 (3%). 59% were Caucasian and 34% African-American. Predictors of pregnancy loss are shown in the table. Lupus anticoagulant at the 1^stvisit was highly predictive of pregnancy loss (and ever being positive was also associated, although less so).

Table 1: Proportion with Pregnancy Loss, by characteristics of the patients.

Patient Characteristic		Proportion (%) with miscarriage	P-value2
All		46/402 (11%)
Age	<20    20-29    30-39    40+	1/13 (8%) 20/202 (10%) 19/172 (11%) 6/12 (50%)	0.38
Ethnicity	Caucasian     African American     Other	28/235 (12%) 14/135 (10%) 4/31 (13%)	0.77
Year of conception	1986-1994     1995-1999     2000-2004     2005+	14/115 (12%) 13/83 (16%) 10/80 (13%) 9/122 (7%)	0.32
RVVT measured in first trimester1	Normal      High (>45)      No first-trimester measure	16/187 (9%) 6/15 (40%) 24/200 (12%)	0.0022
Ever positive for high RVVT	No     Yes     Unknown	26/278 (9%) 20/117 (17%) 0/7 (0%)	0.030
Anticardiolipin-IGG measured in first trimester1	Normal     High     No first-trimester measure	11/127 (9%) 1/11 (9%) 34/264 (13%)	0.96
Anticardiolipin ever present	No     Yes     Unknown	16/158 (10%) 30/241 (12%) 0/3 (0%)	0.41
Moderately active lupus	No    Yes    Unknown	27/281 (10%) 7/27 (26%) 12/94 (13%)	0.012
Low Complement in first trimester	No    Yes    Unknown	23/227 (10%) 11/78 (14%) 12/97 (12%)	0.37
Anti-dsDNA in first trimester	No    Yes   Unknown	18/198 (9%) 15/104 (14%) 13/100 (13%)	0.18
Mean Prednisone dose in first trimester	<10 mg    10+    Unknown	23/220 (10%) 11/88 (13%) 12/94 (13%)	0.60

¹Based on the average of the measures during the first trimester or prior to miscarriage if miscarriage occurred in first trimester.

²Excludes the unknowns in the calculations.

 Conclusion: The strongest predictor of pregnancy loss in SLE is the lupus anticoagulant in the first trimester by dRVVT testing. In contrast to the PROMISSE study, 3 lupus anticoagulant assays were not necessary. In addition, moderate disease activity by the physician global assessment was also predictive of pregnancy loss, but not low complement, anti-dsDNA, or anticardiolipin. These data suggest that treatment of the lupus anticoagulant should be considered, even in the absence of prior history of miscarriage.

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