Women with Ankylosing Spondylitis More Likely to Experience Complications with Pregnancy


An article from Swedish researchers reports on another difficulty that women with ankylosing spondylitis (AS) experience – pregnancy problems. A greater frequency of cesarean or C-section deliveries and offspring more often preterm and small for gestational age (SGA) occur more commonly in AS mothers.

This Swedish Registry study examined 388 deliveries from women with AS patients compared to 1,082 deliveries from mothers without underlying disease. AS women tended to have more associated illnesses or co-morbidities, including hypertension, diabetes, and renal disease.

AS women had more preterm deliveries 9%, versus 4.9% in normal mothers. The frequency of SGA was 1.5% in normal versus almost double, 3.1%, in women with AS. Similar rates of stillbirths were reported, 0.3% and 0.1% for AS women and normal women, respectively.

Preeclampsia is disorder of elevated blood pressure in pregnant women. Preeclampsia is a serious condition associated with organ damage, particularly to the kidneys. Preeclampsia can be life-threatening to mother and child if left untreated. Blood pressure was elevated more commonly in AS women (17%) versus controls (6%).

C-section deliveries were more common in AS women. Emergency 9.8% and elective 16.5% C-sections occurred more commonly in women with AS than the frequency in normal women at a rate of 6.9% and 6.5%, respectively. Preeclampsia was the most common reason for the more frequent C-section deliveries in the women with AS.

AS women taking nonsteroidal anti-inflammatory drugs, disease modifying agents, corticosteroids, or tumor necrosis factor inhibitors had an increased risk of SGA baby or preterm delivery with C-section. However, the direct correlation with the pharmaceutical agents and effects on the delivery and babies cannot be made. Women with more severe disease have increased risk of abnormal pregnancies and deliveries which may not be reversed by the use of medical therapy.

Another important factor in predicting the need for C-section is size of the baby’s head and the aperture of the mother’s pelvis. Individuals with more advanced AS will have sacroiliitis. This disorder can limit the effect of relaxin on the pelvic structures allowing for the natural relaxation of pelvic structures to allow the passage of the baby through the vaginal canal. Without these details in the study, one cannot determine if the mechanical changes in the pelvis had an impact on the increased level of C-sections.

Take Home Message – Women with AS can and do get pregnant, but compared to women without this illness, they need to be monitored carefully during their pregnancy. Awareness of the status of the sacroiliac joints prior to pregnancy when radiographs have no effect on a developing fetus is important. Limiting medicines for AS is ideal during a pregnancy. However, control of disease inflammation is important for mother and child during gestation. The obstetrician should be aware of all these parameters so that at the time of delivery, the best choices are made for a successful birth and healthy mother and child.

Reference: Jakobsson G, Stephansson O, Askling J, et al. Pregnancy outcomes in patients with ankylosing spondylitis: a nationwide register study. Ann Rheum Dis 2015; DOI 10.1136/annrheumdis-2015-207992


Rheumatologic Disorders