Background : Cohort studies show that lupus nephritis (LN) is associated with poor pregnancy outcomes. In North America a significant proportion of LN patients are non-white, a population that has a baseline increased risk of preterm birth, preeclampsia, and fetal growth restriction. This individual participant meta-analysis pooled data to determine the effect of history LN on pregnancy outcomes stratified by maternal race.
Methods : Data from three prospective lupus pregnancy cohorts were included in this analysis. Race was classified as white or non-white; only one pregnancy per patient in women with a first trimester visit were included. Outcomes included fetal loss, preterm birth (<37 weeks), preeclampsia, high disease activity (PGA>1 or SLEDAI>4 during pregnancy), and a composite ‘poor pregnancy outcome’ (fetal loss, preterm birth, preeclampsia or high disease.
Results : The analysis included 312 pregnancies across three cohorts in the US and Canada, of which 22% were to women with history of LN and 46% were to non-white mothers (Figure 1). Women with a history of LN were at increased risk of a poor pregnancy outcome (OR: 1.76; CI: 1.33-2.32), a difference seen in both white and non-white women. A history of LN was not associated with an increase in fetal loss (OR: 0.94; CI: 0.61-1.45). Women with a history of LN had an increased risk of preterm birth overall (OR: 1.50; CI: 1.04-2.17). Women with a history of LN were at increased risk of developing preeclampsia (OR: 2.31; CI: 1.59-3.36). Among white women, preeclampsia was largely driven by a history of LN. In non-white women, the baseline high preeclampsia risk was not significantly increased by a history of LN. A history of LN increased the risk of high disease activity (OR: 2.31; CI: 1.52-3.50). The impact of a history of LN on disease activity in pregnancy was particularly strong among non-white women.
Conclusions : As expected, a history of LN was associated with poor pregnancy outcomes. While fetal loss was not increased, preterm birth, preeclampsia, and disease activity were all more common in women with a history of LN. A history of LN had a greater impact on the rates of preterm birth and preeclampsia in white women, while non-white women without LN had baseline elevations in these complications, making the impact of LN less dramatic.