Psoriasis improvement linked to pregnancy

September 1, 2005

Irvine, Calif. — Recent research validates the long-suspected link between high levels of estrogen occurring during pregnancy and improvement in psoriasis.

The study

The study group included 36 patients who were enrolled during pregnancy (mean week of enrollment: 17 weeks' gestation) and 11 who were enrolled after pregnancy, but less than 24 weeks postpartum. All patients had stable plaque psoriasis.

One of the study's major challenges involved rounding up a significant number of eligible patients. In this regard, Jenny E. Murase, M.D., then a medical student and now a member of UCI's dermatology program (and a co-author of the study), spent more than 2,500 hours of medical and internship time to obtain and interpret all study data and its potential medical significance for female patients with psoriasis.

Over the course of a year, researchers assessed participants, including control patients, a total of five times. These intervals corresponded roughly to pregnant patients' first, second and third trimesters, then six and more than six weeks postpartum. At each visit, patients completed questionnaires concerning factors including psoriasis medications, their perceived stress levels and psoriasis severity scores (1-10 scale) and their psoriatic body surface area (BSA).

Additionally, 19 of the 47 study group patients consented to having blood drawn to check levels of estriol, estrone, estradiol and progesterone. Researchers used methods including progesterone fluorescence immunoassay and estradiol fluorescence immunoassay, estriol fluorescence immunoassay and estrone radioimmunoassay.

Improvement reported

At approximately 30 weeks of pregnancy, 55.3 percent of patients reported an improvement in psoriasis, versus 23.4 percent who reported worsening.

Additionally, 21 percent of patients reported no change during pregnancy. Postpartum, however, 65.2 percent reported a worsening of psoriasis, versus 8.7 percent who reported improvement.

BSA analysis supports patients' assessments of their conditions. When researchers examined the actual psoriatic BSA change at 30 weeks, for example, setting a change of greater than 3 percent BSA as a cutoff point for improvement or worsening, they still found that twice as many patients improved as worsened (14/30 percent, 7/50 percent, respectively).

Hormone levels

To assess the relationship between hormone levels and psoriatic change, researchers moreover calculated the relative reduction of psoriatic BSA in pregnancy for two groups of patients: those who had at least 10 percent BSA impacted by psoriasis at the beginning of pregnancy, and all patients who had hormone levels measured between 29 and 32 weeks' gestation.

In both groups, a significant correlation between the estrogen-progesterone ratio and psoriatic change emerged. Likewise, researchers found significant or near-significant correlations between estradiol and psoriatic change, along with a near-significant correlation between estradiol and psoriatic change in the second group of patients analyzed.

However, no correlations between psoriatic change and estrone and progesterone levels appeared.

BSA improvement

Additionally, researchers noted a statistically significant improvement in BSA among the study group between 10 and 20 weeks' gestation, as well as a statistically significant worsening between weeks 30 and 40 (p<0.001).