Treatment of Pregnancy RA

Inclusion Criteria: 1. A diagnosis of RA, as defined by 2010 ACR/EULAR criteria 2. DAS 28∙ESR\<2.6 under the treatment of DMARDs 3. Subjects consider pregnancy, but not pregnant yet 4. Participant expects to continue CZP therapy throughout pregnancy and for at least 24 weeks postpartum 5. Participant has a negative interferon gamma release assay (IGRA) or tuberculin skin test (TST) within the prior 6 months, and there has been no change in the study participant's clinical status, or social, family, or travel history. Participants with documented Bacillus Calmette-Guérin (BCG) vaccine and at low risk for tuberculosis (TB) may enroll without having a TB test performed Exclusion Criteria: 1. Participant has any medical or psychiatric condition that, in the opinion of the investigator, could jeopardize or would compromise the study participant's ability to participate in this study 2. Participant is not permitted to enroll into the study if she meets any of the following TB exclusion criteria:(1) Known active TB disease; (2) History of active TB involving any organ system; (3) Latent TB infection; (4) High risk of acquiring TB infection; (5) Current nontuberculous mycobacterial (NTM) infection or history of NTM infection (unless proven to be fully recovered) 3. Study participant is taking a prohibited medication or has taken a prohibited medication 4. Live vaccine(s) within 1 month prior to Screening, or plans to receive such vaccines during the study 5. Study participant has any clinically significant pregnancy-related clinical or test abnormality, as judged by the investigator 6. Study participant had a positive or indeterminate interferon gamma release assay (IGRA) or tuberculin skin test (TST) at Screening. In case of indeterminate result, a retest is allowed if time permits; 2 results of indeterminate require exclusion of the study participant