With an average age of diagnosis of 28 years, and one of two incidence peaks occurring at 15-30 years, psoriasis affects many women in the midst of their reproductive years. The prospect of pregnancy – or the reality of a surprise pregnancy – drives questions about heritability of the disease in offspring, the impact of the disease on pregnancy outcomes and breastfeeding, and how to best balance risks of treatments with risks of uncontrolled psoriasis and/or psoriatic arthritis (PsA).
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While answers to these questions are not always clear, discussions about pregnancy and psoriasis management “shouldn’t be scary,” said Jenny E. Murase, MD, a dermatologist who speaks and writes widely about her research and experience with psoriasis and pregnancy. “We have access to information and data and educational resources to [work with] and reassure our patients – we just need to use it. Right now, there’s unnecessary suffering [with some patients unnecessarily stopping all treatment].”
Dr. Jenny E. Murase
Much has been learned in the past 2 decades about the course of psoriasis in pregnancy, and pregnancy outcomes data on the safety of biologics during pregnancy are increasingly emerging – particularly for tumor necrosis factor (TNF)–alpha inhibitors.
Ideally, since half of all pregnancies are unplanned, the implications of therapeutic options should be discussed with all women with psoriasis who are of reproductive age, whether they are sexually active or not. “The onus is on us to make sure that we’re considering the possibility [that our patient] could become pregnant without consulting us first,” said Dr. Murase, associate professor of dermatology at the University of California, San Francisco, and director of medical consultative dermatology for the Palo Alto Foundation Medical Group in Mountain View, Calif.
Lisa R. Sammaritano, MD, associate professor of clinical medicine at Weill Cornell Medicine and a rheumatologist at the Hospital for Special Surgery, both in New York, urges similar attention for PsA. “Pregnancy is best planned while patients have quiescent disease on pregnancy-compatible medications,” she said. “We encourage [more] rheumatologists to be actively involved in pregnancy planning [in order] to guide therapy.”
Dr. Lisa R. Sammaritano
The impact of estrogen
Dr. Murase was inspired to study psoriasis and pregnancy in part by a patient she met as a medical student. “She had severe psoriasis covering her body, and she said that the only times her psoriasis cleared was during her three pregnancies,” Dr. Murase recalled. “I wondered: What about the pregnancies resulted in such a substantial reduction of her psoriasis?”
She subsequently led a study, published in 2005, of 47 pregnant and 27 nonpregnant patients with psoriasis. More than half of the patients – 55% – reported improvements in their psoriasis during pregnancy, 21% reported no change, and 23% reported worsening. Among the 16 patients who had 10% or greater psoriatic body surface area (BSA) involvement and reported improvements, lesions decreased by 84%.
In the postpartum period, only 9% reported improvement, 26% reported no change, and 65% reported worsening. The increased BSA values observed 6 weeks postpartum did not exceed those of the first trimester, suggesting a return to the patients’ baseline status.
Earlier and smaller retrospective studies had also shown that approximately half of patients improve during pregnancy, and it was believed that progesterone was most likely responsible for this improvement. Dr. Murase’s study moved the needle in that it examined BSA in pregnancy and the postpartum period. It also turned the spotlight on estrogen: Patients who had higher levels of improvement also had higher levels of estradiol, estrone, and the ratio of estrogen to progesterone. However, there was no correlation between psoriatic change and levels of progesterone.
To promote fetal survival, pregnancy triggers a shift from Th1 cell–mediated immunity – and Th17 immunity – to Th2 immunity. While there’s no proof of a causative effect, increased estrogen appears to play a role in this shift and in the reduced production of Th1 and Th17 cytokines. Psoriasis is believed to be primarily a Th17-mediated disease, with some Th1 involvement, so this down-regulation can result in improved disease status, Dr. Murase said. (A host of other autoimmune diseases categorized as Th1 mediated similarly tend to improve during pregnancy, she added.)
Information on the effect of pregnancy on PsA is “conflicting,” Dr. Sammaritano said. “Some [of a limited number of studies] suggest a beneficial effect as is generally seen for rheumatoid arthritis. Others, however, have found an increased risk of disease activity during pregnancy ... It may be that psoriatic arthritis can be quite variable from patient to patient in its clinical presentation.”
At least one study, Dr. Sammaritano added, “has shown that the arthritis in pregnancy patients with PsA did not improve, compared to control nonpregnant patients, while the psoriasis rash did improve.”
The mixed findings don’t surprise Dr. Murase. “It harder to quantify joint disease in general,” she said. “And during pregnancy, physiologic changes relating to the pregnancy itself can cause discomfort – your joints ache. The numbers [of improved] cases aren’t as high with PsA, but it’s a more complex question.”
In the postpartum period, however, research findings “all suggest an increased risk of flare” of PsA, Dr. Sammaritano said, just as with psoriasis.