While the prevalence of psoriasis is similar between men and women, the burden of disease can differ.
For women, diagnosis and treatment initiation may occur during peak reproductive years, which adds an additional layer of complexity to management. Additionally, it is known that psoriasis activity can fluctuate with hormonal changes, including those which occur during pregnancy.
“We know that the primary risk factor for psoriasis is a patient’s genetic make-up. However, female hormones can influence disease severity,” says Jenny Murase, M.D., the Associate Clinical Professor of Dermatology at the University of California, San Francisco and Director of Medical Consultative Dermatology, at the Palo Alto Medical Foundation in Mountain View, California.
Estrogen and Psoriasis
Estrogen, in particular, has shown to affect the severity of psoriasis in some female patients. Research has shown that during pregnancy, many female patients report an improvement in psoriasis symptoms. “When levels of estrogen increase [during] pregnancy, psoriasis tends to improve, and when it decreases right after baby is born, it worsens,” Dr. Murase explains. A study of women with psoriasis showed that 55 percent of pregnant women who also have psoriasis reported an improvement in their disease, which correlated with a high level of estrogen. However, only 9 percent of patients reported an improvement during the postpartum time. Furthermore, data from that study also showed that psoriatic body surface area significantly decreased between 10 to 20 weeks gestation and increased significantly by 6 weeks post-partum. 
Furthermore, there is evidence that estrogen receptors are a member of the superfamily of nuclear receptors for steroid hormones. “The estrogen receptor is a nuclear receptor. Estrogen binds to these receptors as vitamin D, corticosteroids and other thyroid hormones do, and these medications have been used as psoriasis treatments,” says Dr. Murase.
Estrogen is one of two main sex hormones that women have (the other is progesterone) and its levels fluctuate through each month. Highest levels can be seen in the middle of a menstrual cycle and lowest during menstruation; levels drop at menopause.  Dr. Murase tells us that there may be fluctuations in disease severity based on the menstrual cycle following a similar pattern as pregnancy. “There have been reports that the high estrogen oral contraceptives in the 1970s may have been associated with some psoriasis disease improvement,” she says. It is understood that sex hormones influence inflammation, and that the increased levels of estrogen at menarche could potentially influence Th1 and Th2 immune responses. 
“Whenever anyone is on therapy for a chronic condition, health care providers have to consider the risk to the fetus,” says Dr. Murase.
Light therapy is probably the first and most benign therapy, with NB-UVB generally considered to be the safest form of phototherapy for women of reproductive age. However, folic acid levels may decrease over time from photodegradation. A 2019 study examining effects of NB-UVB exposure on serum folate or cobalamin levels found after 12 NB-UVB exposures, there was a significant decrease of serum folate (and cobalamin).  “Folic acid has to be at a certain level to prevent neural tube defects. HCPs should make sure their female patients are taking folic acid while receiving light treatments, so their folic acid stores are strong,” Dr. Murase says.
Dr. Murase notes that patients who are in peak reproductive years cannot take Soriatane or acitretin within 3 years of conceiving. Methotrexate is a teratogen and health care providers (HCPs) must treat these patients like patients using Accutane, who are encouraged to use two forms of contraception and regularly check for pregnancy with pregnancy tests. She adds that cyclosporine is a go-to for horrible flares during pregnancy, but it a very strong treatment and requires lab work. Some of the newer oral medications have very little safety data in pregnancy. “If we don’t have data, we don’t advise it,” Dr. Murase says.
To date, tumor necrosis factor (TNF) inhibitors have the most data to support safe use during pregnancy. In order for treatments to be transferred to the fetus, they must go through the placenta. In fact, certolizumab pegol is a PEGylated TNF-a agent, meaning it is not actively transported across the placenta during pregnancy. 
However, Dr. Murase questions what the immunosuppression is in the infant as a result of the mother taking biologics. She explains that there was a case study about a baby that was born to a mother with Crohn’s disease. She had received infliximab throughout her pregnancy. At the time, they resided in a region in England with a high rate of tuberculosis (TB). After birth, when the baby received the Bacillus Calmette–Guérin (BCG) vaccination for TB, their health declined and, unfortunately, they died of disseminated BCG a few weeks later. 
“Antibodies are only needed right before birth. They start to cross placenta early 2nd trimester and during the 3rd trimester the antibodies shoot up exponentially. The baby gets a huge boost of antibodies right before they’re born. But we’re not following these babies – are they experiencing an increased rate of illness?” Dr. Murase asks.
Unmet Needs of Women
According to a National Psoriasis Foundation (NPF) survey about family planning and psoriasis, only 7.4 percent of patients stated that a discussion about family planning was initiated by their HCP. Furthermore, only 28.6 percent of patients with psoriasis who were trying to conceive consulted the HCP treating their psoriatic disease. The majority of patients looked to the internet for information. Data also showed that many patients delayed informing their treatment provider and some did not discuss their pregnancy at all.  Another survey revealed that 54 percent of women of childbearing age admitted to delaying their decision to have children. They cited the main fear was passing on health issues to their child. [8, 9]
“The issue isn’t planning for pregnancy, because 50 percent of pregnancies are unplanned. Majority of the time, people have not discussed planning with their specialists. The question shouldn’t be how to rethink therapy, but instead to question if this woman is of childbearing age and could get pregnant. And if so, what treatment has the best safety data,” Dr. Murase says. “The onus is on us as medical providers. We need to initiate the conversation and understand what could happen if we don’t.”
Furthermore, an NPF survey showed that majority of patients who had been pregnant stopped treatment of any kind, and in 40 percent of those cases, the decision was initiated by the patient themselves.  Data from another survey showed that often, patients felt they had to choose between treatment and breastfeeding during the postpartum period, and some felt they lacked information regarding the impact of treatment decisions on breastfeeding. [8, 9]
“When I’m prescribing a therapy, I err on the side of caution,” says Dr. Murase.