Pregnancy can trigger psoriasis for the first time, though it’s uncommon. More often, pregnancy changes the course of psoriasis that already exists, and the direction of that change surprises many women: the majority actually improve. In a study of 102 patients with a specific type of psoriasis (generalized pustular), pregnancy was identified as the trigger in 17 cases. For women who already have psoriasis, about 55% see their skin get better during pregnancy, roughly 21-23% notice no change, and 23-26% experience worsening.
Why Psoriasis Often Improves During Pregnancy
Psoriasis is driven by an overactive immune response, specifically by immune cells that promote inflammation. During pregnancy, the body deliberately dials down this type of inflammation to protect the developing baby from being attacked by the mother’s immune system. Rising estrogen and progesterone shift the immune system away from the inflammatory profile that fuels psoriasis and toward a calmer, more tolerant state. This is why more than half of pregnant women with psoriasis notice their skin clearing up.
The improvement tends to follow a timeline. Skin often starts getting better between 10 and 20 weeks of pregnancy, with the peak improvement around 30 weeks. After that point, some women notice their symptoms creeping back even before delivery.
Why Some Women Get Worse Instead
Not everyone benefits from these hormonal shifts. About one in four pregnant women with psoriasis sees their condition worsen. The reasons aren’t fully understood, but individual variation in hormone levels, stress, and the unpredictable nature of psoriasis itself all play a role. Some women also stop their medications when they learn they’re pregnant, which can trigger a rebound flare.
In rare cases, pregnancy can trigger a severe form called generalized pustular psoriasis of pregnancy (historically known as impetigo herpetiformis). This condition typically appears in the third trimester and looks different from typical plaque psoriasis. It presents as red patches studded with small pustules, usually starting on the arms and legs before spreading to the trunk. The pustules are sterile, meaning they aren’t caused by infection. Beyond the skin, it can cause fever, nausea, vomiting, and diarrhea. The most serious concern is a drop in calcium levels, which in extreme cases can lead to seizures. This condition requires close monitoring and hospital-based care, but it’s rare enough that most women with psoriasis will never experience it.
The Postpartum Flare
Even women whose psoriasis improved beautifully during pregnancy should be prepared for what comes after delivery. The hormonal protection disappears quickly once the baby is born, and the immune system snaps back to its pre-pregnancy inflammatory state. In one study, 65% of women reported worsening psoriasis after delivery, while only 9% continued to improve. By six weeks postpartum, the average affected skin area had doubled compared to late pregnancy. This flare is significant enough that planning ahead with a dermatologist before delivery can make a real difference in managing it.
Managing Psoriasis Safely During Pregnancy
Treatment options narrow during pregnancy, but they don’t disappear. Mild to moderate strength topical steroid creams remain a mainstay and have a reassuring safety record. A large Cochrane review found no link between these lower-potency creams and birth defects, preterm delivery, or low birth weight. Higher-potency topical steroids are a different story. There’s a probable association between heavy use of potent topical steroids during pregnancy and lower birth weight, particularly when the total amount used exceeds about 300 grams over the course of the pregnancy. The practical takeaway: milder creams applied to limited areas carry very little risk, while strong formulations used over large areas for months deserve more caution.
For women who need more than topical treatment, narrowband UVB phototherapy is considered a safe option during pregnancy. It uses a specific wavelength of ultraviolet light to calm inflammation in the skin without systemic medication entering the bloodstream. Early concerns that phototherapy might lower folate levels (important for preventing neural tube defects) haven’t been supported by the evidence at typical treatment doses. Standard folic acid supplementation, which is already recommended for all pregnant women, provides adequate protection.
Among biologic medications, one anti-inflammatory injection stands out for its unique molecular structure: it lacks the component that allows drugs to cross the placenta. This means minimal to no transfer to the baby, making it the biologic with the most reassuring pregnancy data. Many other systemic psoriasis medications, particularly oral ones like methotrexate and acitretin, are strictly off-limits during pregnancy due to known risks of birth defects.
What Determines Whether Your Psoriasis Improves or Worsens
There’s no reliable way to predict which direction your psoriasis will go during pregnancy. The pattern doesn’t always repeat across pregnancies either. One pregnancy might bring dramatic clearing while the next brings a flare. Survey data shows that about 77% of women notice some change in their psoriasis during pregnancy, so staying the same is actually the least common outcome. The best approach is to work with a dermatologist before conception or early in pregnancy to establish a treatment plan that’s both effective and safe, with a specific strategy ready for the postpartum period when flares are most likely.