Updated Information on Pregnancy and AS
Ankylosing spondylitis (AS) is an autoimmune condition, a form of arthritis that causes chronic inflammation in certain joints. Ankylosing describes the abnormal stiffness in joint movement because of the joining or fusion of the bones. Spondylitis refers to inflammation of the spine.
AS is known to cause chronic, often severe pain and stiffness, most often in the spine and hips. This condition, one that affects women of childbearing age, has led to questions as to ask how AS might affect pregnancy.
A recently released study suggests that although pregnancy outcomes are generally favorable for women with AS, women with active disease who use corticosteroids may be at increased risk for adverse pregnancy outcomes, including preterm labor, and delivery by Caesarian section.
AS does not influence conception
Having ankylosing spondylitis has not been shown to be a factor in fertility, the ability of a woman to conceive. The majority of women are not affected during pregnancy, with the disease typically remaining stable. Yet it appears that the disease state (level of activity of the disease) may have some influence over factors associated with carrying the pregnancy to full term and method of delivery.
Impact on pregnancy outcomes
A limited number of studies have been conducted to evaluate the outcome of AS pregnancies compared to healthy control populations. A 2019 report is a population-based case-control study dedicated to pregnancy outcomes in AS in Sweden. It looked at 301 pregnant women with AS and 1082 healthy controls.
Results reported a higher risk for preterm birth, at two levels, moderate preterm (32-36 weeks) and very preterm (<32 weeks). Higher rates of Caesarean deliveries, including the emergency and elective cases, were also noted when compared to controls. Yet the evaluation also remarked that it was the presence of high disease activity at intake, combined with overall corticosteroid use (38%), that accounted for the high rates in this population.
What the data says
Prospective cohort study using data from the U.S. and Canada used data from the Organization of Teratology Information Specialists (OTIS) Autoimmune Disease in Pregnancy Project.2 Questionnaires were administered to participants before and after pregnancy. Although the study populations were relatively small, they identified a link between high Routine Assessment of Patient index score and Caesarian delivery and also between 2nd trimester corticosteroid use and preterm delivery.2 Preterm delivery cases also increased the likelihood that infants would require medical care and hospitalization in a neonatal intensive care unit (NICU).2
The American College of Rheumatology 2016 guidelines recommend against the use of systemic corticosteroids for the treatment of AS except in certain short-term circumstances.2 Women planning to get pregnant should discuss with their physicians all medications they presently take to determine which they can continue to use safely during pregnancy.
Some medications used to manage AS, including corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs), may not be safe to use during pregnancy. Others, including certain biologics, may be acceptable. Your doctor can explain any impact on fertility, possible obstetrical problems, and risk of birth defects.
Caesarean section is often considered an elective decision for anatomical reasons in women with AS.2 The inflammation and associated pain in the hips and spine can result in a more difficult vaginal delivery. The administration of an epidural, the injection of a pain block directly into space around the spinal cord which numbs the lower half the body during delivery, can also be more complicated for women with AS, due to the existing inflammation. The decision to have a cesarean should be discussed in advance with your obstetrician as should consider your personal AS circumstances.
Good disease management and control, including the minimization of corticosteroid usage, can help improve pregnancy outcomes in women with AS.2
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