There are several well-known risk factors for herpes zoster (HZ), including age and a compromised or suppressed immune system. One factor that is often not mentioned is gender.
The CDC reports that a number of studies have revealed that more women than men develop shingles, although it states that the reason for the disparity is not known. One recent prospective study concluded that HZ incidence was “significantly associated with being female” after finding that women accounted for 62% of the cases reviewed.
One plausible explanation for the higher HZ incidence among women is hormones. Shingles is a reactivation of the opportunistic varicella virus that is often triggered by physiologic stress. Two stages of life that are unique to women—pregnancy and menopause—are times of intense physiologic stress associated with hormones.
OBGYN Kathleen Gardner, MD, sees the connection regularly in her Ithaca, NY, practice. She firmly believes that hormonal imbalances related to pregnancy and menopause contribute to a woman’s chances of developing shingles.
“Postpartum women have a significant drop in estrogen and progesterone after giving birth. Many immunologic disorders and responses to pathogens can go awry postpartum, so it makes sense that a lot of autoimmune disorders pop up,” she explains. “Menopause is associated with cessation of function of the ovaries and a decreased production of estradiol, and you don’t get progesterone production. Both are associated with hiccups in immune function.”
Gardner adds that another shared complaint of postmenopausal and postpartum women—the disruption of normal sleep patterns—can also negatively affect immune function.
While postmenopausal women typically fall near or within the 50-and-older age group that is most at risk for developing shingles, postpartum women rarely do. Consequently, a diagnosis of shingles comes as a surprise to them, says Gardner.
“We do see a lot of peculiar rashes in pregnancy, so it’s not uncommon for us to be the first people to identify the shingles rash,” she says. “They are shocked initially because it’s not on their radar. They’re thinking about milk production, not getting enough sleep, healing, and whether the baby is growing. It’s definitely not the first thing that they think of.”
Gardner advises all women to check their chickenpox status before becoming pregnant, and her practice screens all patients before or during pregnancy. If a woman cannot recall having chickenpox, or if she was never vaccinated against it, Gardner orders a varicella titer to see if she has been exposed and has immunity. If not, she is vaccinated after delivery, while she’s still in the hospital.
Read More: Guidelines for Shingles Vaccinations
This policy is in line with the CDC’s advice that pregnant women with no immunity to chickenpox should not receive the varicella vaccine because the effects of the virus on the fetus are unknown. Nonpregnant women who are vaccinated should avoid becoming pregnant for one month after each injection. Unlike chickenpox, HZ is not associated with increased fetal risk, and newborns do not appear to be at risk of infection from maternal zoster that develops near delivery.