Background/Purpose: Systemic inflammatory conditions such as
systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriatic
arthritis (PsA), and ankylosing spondylitis (AS)
affect many women during their childbearing years. Empirical data describing
the time-trends and patterns of use of immunosuppressive agents during
pregnancy in routine practice are scarce. Therefore, we designed this study to
describe patterns and secular trends in use of immunosuppressive agents in
pregnant women with SLE, RA, PsA, or AS.

Methods: A cohort of women with SLE, RA, PsA,
or AS enrolled in public (Medicaid, 2001-2010) or private (OptumClinformatics,
2004-2012) health insurance was identified and women filling prescriptions for immunosuppressives– including steroids, non-biologic
disease-modifying agents, and biologics- in the 3-month period immediately
prior to their pregnancy were included. The proportion of women continuing or
discontinuing individual agents during pregnancy was reported. Annual
prescription fill rates, estimated after accounting for patient characteristics
and random variability from year-to-year in mixed-effect regression models,
were used to conduct time-trends analysis.

Results: A total of 2,645 women actively treated with
immunosuppressive agents prior to pregnancy were included. More women with PsA or AS stopped filling immunosuppressive prescriptions
in pregnancy (61%) than those with SLE (26%) or RA (34.5%).  From the
first to the third trimester, the proportion of women filling prescriptions for
immunosuppressive agents decreased across all indications. Overall, steroids
(48.4%) and hydroxychloroquine (27.1%) were the most frequently used agents in
pregnancy. The rates (reported per 100 deliveries in our cohort)  for
steroid prescription fills during pregnancy fell significantly from 54.4 to
42.4; while rates for biologics increased from 5.1 to 16.6 between 2001 and
2012 (p<0.001 for both trends).

Conclusion: Steroids and hydroxychloroquine remain the most
widely prescribed treatment options in pregnancy; but the use of biologics is
becoming increasingly common.

Figure: Time-trends in use of immunosuppressive
agents during pregnancy in a cohort of women with systemic lupus erythematosus,
rheumatoid arthritis, ankylosing spondylitis or psoriatic arthritis.

* Adjusted for maternal characteristics (age, region),
insurance type (Medicaid or private), case-mix (underlying treatment
indication- SLE, RA, PsA, or AS), and random
variability across years using a mixed regression model.