Pregnancy Outcomes Vary in Women with Psoriatic Arthritis

Katarina Remaeus, PhD

A team of investigators led by Katarina Remaeus, PhD, Karolinska Institutet, Department of medicine Solna, Clinical Epidemiology Division, conducted a cohort study in order to evaluate the impact that antirheumatic treatment had on pregnancy outcomes in women with psoriatic arthritis (PsA).

Investigators found that the risk of adverse outcomes increased the most in pregnancies with antirheumatic treatment, especially those treated with biologic disease modifying antirheumatic drugs (bDMARDs), during pregnancy, compared with non-psoriatic arthritis.

Of the few previous studies that describe maternal and neonatal pregnancy outcomes in women with psoriatic arthritis, some indicated an increased risk of preterm birth and cesarean delivery.

The Study

Investigators conducted a nationwide Swedish register-based cohort study of births from July 2007-December 2017 to compare pregnancy outcomes, with a focus on presence and timing of antirheumatic treatment in pregnancies with exposure to psoriatic arthritis compared with pregnancies without exposure to PsA.

Exposure to psoriatic arthritis was defined by women with a diagnosis of psoriatic arthritis in the NPR according to International Classification of Diseases (ICD)-10 codes L405, M070-1, and M073. First and subsequent pregnancies of these women were identified by linkage to the medical birth registry (MBR).

Unexposed pregnancies or non-psoriatic arthritis pregnancies were identified from the NPR and by the medical birth registry, the first and subsequent singleton pregnancies to women without diagnosis of inflammatory joint disease sampled from a pre-existing linkage.

In total, 921 psoriatic arthritis pregnancies and 9210 non-psoriatic arthritis pregnancies were identified by investigators. There were 10 unexposed pregnancies sampled matched on year of birth, maternal age, and parity.

The Treatment

Investigators used the prescribed drug register (PDR) to gather information on dispensed prescriptions for antirheumatic treatment. Antirheumatic treatment was defined as oral corticosteroids, conventional (cs) or biological (b) disease modifying antirheumatic drugs (DMARDs).

Of the 921 psoriatic arthritis pregnancies, 495 were pregnancies without any prior treatment for PsA in the year before pregnancy up until delivery and 426 were pregnancies with presence of any antirheumatic treatment within the same time frame.

The pregnancies were then further stratified, all based on presence and timing of maternal antirheumatic treatment and compared to the matched 9210 non-psoriatic pregnancies.

The Results

Results demonstrated that pregnancy outcomes varied with timing, presence and type of antirheumatic treatment.

The risk of adverse outcomes were found to be most increased in pregnancies with antirheumatic treatment, especially biologic disease modifying antirheumatic drugs, during pregnancy, compared with non-psoriatic arthritis.

Overall, the risk of preterm birth was increased for the main analysis of the 921 psoriatic arthritis pregnancies (aOR of 1.69, 95%CI 1.27-2.24).

The increased risks for spontaneous onset and medically indicated preterm birth were statistically significant, as well as for moderately, but not for very preterm birth. Elective (aOR 1.77, 95%CI 1.43-2.20) and emergency (aOR 1.42 95%CI 1.10-1.84) cesarean delivery showed an increased risk also.

The results displayed no differences in risk of pre-eclampsia, gestational diabetes or hypertension, small for gestational age, or large for gestational age in psoriatic arthritis pregnancies compared to non-psoriatic arthritis pregnancies.

Investigators recommended that all women with psoriatic arthritis should be counseled about pregnancy outcomes and receive individualized monitoring during pregnancy, regardless of antirheumatic treatment.

The study "Pregnancy outcomes in women with psoriatic arthritis with respect to presence and timing of antirheumatic treatment" was published in Arthritis & Rheumatology.