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MAMA - looking at whether stopping or continuing biologics in pregnancy is good or bad for women with inflammatory arthritis


1-2% of women are affected by inflammatory arthritis such as rheumatoid arthritis, psoriatic arthritis, axial spondyloarthropathy or juvenile idiopathic arthritis. Many are treated with new medications known as 'biologics'. More women with inflammatory arthritis are considering starting a family, because treatment with biologics means they are more able to manage their arthritis. They may need to make difficult decisions around treatments during pregnancy.

Uncontrolled arthritis can lead to worse outcomes in pregnancy, so managing arthritis well is very important. Biologics are often avoided during pregnancy because of limited understanding of how these drugs impact pregnancy or arthritis activity during this time. There are concerns about possible effects of these drugs on babies' immune systems, and some baby vaccinations are routinely delayed. Until recently, most women were advised that they should stop their biologic drugs during pregnancy and avoid these drugs in the second and third trimester; however, due to mounting evidence of their safety for mums and babies during pregnancy, very recent national guidance now states than women can stay on biologics throughout pregnancy. It is currently unknown whether there is any benefit to this strategy in terms of arthritis disease control. We also know that certain other medicines used to treat arthritis flares in pregnancy, such as steroids, can pose potential harm.

We want to answer the question:

In pregnant women with inflammatory arthritis, does continuing biological disease modifying anti-rheumatic drugs ('biologics') throughout pregnancy, compared to stopping them before the third trimester result in better arthritis symptom control?

How we will do this?

To answer this question, pregnant women at less than or equal to 28 completed weeks' gestation prescribed a regularly dosed biologic for inflammatory arthritis will be put at random into one of two groups:

  • to continue their biologic throughout pregnancy
  • to stop their biologic before the third trimester (28 weeks) of pregnancy, restarting no earlier than 2 weeks post-pregnancy

Women will be asked to complete a simple arthritis symptom severity questionnaire monthly via an app or in written format. After their baby is born, women will be asked to report symptoms up to 12 months post-pregnancy. Some families will be asked if they would be happy for their baby to have blood tests to check their immune response to vaccinations. Mums and babies will be followed up until 2 years post-pregnancy, to assess their general health and their baby's development.

The MAMA trial will recruit 328 women in approximately 35 obstetric units with a maternal medicine service in the 16 Maternal Medicine Networks in England over a 4 year recruitment period.

MAMA is coordinated by the National Perinatal Epidemiology Unit Clinical Trial Unit (NPEU CTU) at the University of Oxford and is funded by the National Institute of National Institute for Health and Care Research (NIHR) Health Technology Assessment (HTA) programme.

For more information, please contact the MAMA team at

Updated: Thursday, 15 February 2024 13:51 (v3)