Premature births are more common in pre-vaccinated people


ATLANTE New research presented this week at ACR Convergence 2022, the annual meeting of the American College of Rheumatology, found a greater number of preterm births in unvaccinated pregnant patients compared to fully vaccinated pregnant patients with rheumatic diseases and COVID-19 (Abstract #0950).

Premature birth and low birth weight are more common in patients with certain types of rheumatic and musculoskeletal diseases, often due to higher disease activity during pregnancy. Less is known about pregnancy outcomes in women with rheumatic diseases and COVID-19 infection and even less about the effect of vaccination on outcomes. This study aimed to fill some of these major gaps.

Study researchers reviewed data from 73 pregnant patients who were enrolled in the Global Rheumatology Alliance COVID-19 Registry from March 2020 to February 2022, as well as follow-up surveys of healthcare professionals. The registry is an international case notification registry created at the start of the pandemic to help guide medical care for people with rheumatic or immunosuppressed conditions and COVID-19.

The results were organized according to the vaccination status of pregnant patients before COVID-19 infection. Those who received no vaccine or a dose were defined as unvaccinated or partially vaccinated. Patients who received two or more doses were defined as fully vaccinated. It should be noted that none of the participants received the single-dose Johnson & Johnson vaccine.

Lupus was the most common RMD among the 73 pregnant patients (n=17), followed by rheumatoid arthritis (n=16). Nearly 70% of patients were in remission at the time of COVID-19 diagnosis; only 4.1% reported severe disease activity.

At the time the data was extracted from the registry, 24.7% of pregnancies were ongoing, while 50 of 55 terminated pregnancies resulted in live births. The rest ended in miscarriage, stillbirth or termination of pregnancy for the health of the patient.

A majority of women, 44, were unvaccinated when diagnosed with COVID-19; three had received one dose and 26 had received two or more doses. COVID-19 hastened childbirth in nearly seven percent of unvaccinated women, compared to nearly four percent of fully vaccinated women.

More striking were the differences in neonatal outcomes. Among terminated pregnancies, there were more preterm births in unvaccinated patients than in vaccinated patients (29.5% versus 18.2%, respectively). Low birth weight was the most frequent neonatal complication (24% of live births), followed by small size for gestational age (14%).

“There are still many unknown and poorly understood things about the pathogenesis of COVID-19. This is why this study is so important despite the small number of pregnancies included,” says Sinead Maguire, MB BCh BAO MRCPI, rheumatology researcher at Toronto Western Hospital in Canada and lead author of the study.

“Studies in the general population have demonstrated dysfunction of the renin-angiotensin system leading to increased rates of pre-eclampsia in pregnant women with COVID-19. Postpartum, placental fetal vascular malperfusion was also noted on the histology of women infected with COVID-19. It is not known if or how the COVID-19 vaccine interferes with these processes. But [given the study results]we encourage vaccination against COVID-19 in pregnant women with rheumatic diseases.

Dr. Maguire notes that in the study, only a few patients needed drugs for COVID-19, regardless of their vaccination status.

“Hospitalization rates were also similar among all vaccination cohorts, although the prevalence of hospitalizations was higher than expected, possibly for maternal and fetal surveillance. This would imply that the severity of COVID-19 was similar between vaccinated and partially vaccinated or unvaccinated women. This was an unexpected result, given the differences in obstetric and neonatal outcomes,” she says.

Dr. Maguire explains that the Global Rheumatology Alliance COVID-19 Registry will create a summary of the study results and distribute them to patients and patient advocacy groups to encourage COVID-19 vaccination in rheumatology patients.

“The findings may also be used in future studies to better understand the impact of COVID-19 vaccination on pregnancy outcomes in patients with rheumatic diseases,” Dr. Maguire said.

The main limitations of the study were the small number of women and pregnancies included and the inability to adjust for confounders such as disease activity, comorbidities and medications. Its strengths include a diverse mix of ethnicities and rheumatic and musculoskeletal conditions, reliability of data, and inclusion of vaccination status in data collection – “factors that have provided a unique perspective on pregnancy among women with rheumatic diseases in the context of COVID-19.”


About ACR Convergence

ACR Convergence, the annual meeting of the American College of Rheumatology, is where rheumatology comes together to collaborate, celebrate, come together and learn. With over 320 sessions and thousands of abstracts, it offers a superior combination of basic science, clinical science, business education and interactive discussions to improve patient care. For more information about the meeting, visit, or join the conversation on Twitter by following the official hashtag (#ACR22).

About the American College of Rheumatology

Founded in 1934, the American College of Rheumatology (ACR) is a nonprofit professional association dedicated to advancing the specialty of rheumatology that serves nearly 8,500 physicians, healthcare professionals, and scientists worldwide. In doing so, RAC provides education, research, advocacy and practice management support to help its members continue their innovative work and provide quality patient care. Rheumatology professionals are experts in the diagnosis, management and treatment of over 100 different types of arthritis and rheumatic diseases. For more information, visit

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