The Mepolizumab Pregnancy Exposure Study

The Mepolizumab Pregnancy Exposure Study is a prospective, observational, exposure cohort study of pregnancy outcomes in women exposed to mepolizumab during pregnancy compared to pregnancy outcomes in women who have not used mepolizumab during pregnancy but have used other anti-asthmatic medications (treated disease comparison group), and pregnancy outcomes in women exposed to other non-teratogenic agents (non-asthmatic comparison group).

The purpose of the study is to monitor planned and unplanned pregnancies exposed to mepolizumab and to evaluate the effect of this medication relative to the primary pregnancy outcome of major birth defects and the secondary pregnancy outcomes of preterm delivery, small for gestational age infants and spontaneous abortion or stillbirth.


  • One to four phone interviews during pregnancy with at least one interview after delivery.
  • Releasing medical records during pregnancy and for their baby up to one year of age
  • No travel or changes to healthcare routine are required
  • Patients may reside anywhere in the US and Canada.

Eligibility Criteria:

Three cohorts of pregnant women will be enrolled:

  • Cohort 1 will consist of a mepolizumab-exposed cohort with exposure to at least one dose of the drug from 8 weeks prior to the first day of the last menstrual period (LMP) to the end of pregnancy.
  • Cohort 2 will consist of a disease cohort with treated asthma who has not been exposed to mepolizumab within 8 weeks prior to the first day of the LMP or throughout pregnancy.
  • Cohort 3 will consist of a non-asthmatic cohort who have no current diagnosis of asthma and have not been exposed to any known human teratogen but may have potentially been exposed to non-teratogenic agents.

Enrolment should take place as early in the pregnancy as possible and prior to any knowledge of the pregnancy outcome. Healthcare providers and pregnant women are encouraged to notify GSK Safety Department of any pregnancies where exposure to mepolizumab has occurred and the pregnancy outcome is already known.

An Eligible pregnant woman may self-enrol at any time during their pregnancy or, with their consent, their HCP may enrol them on their behalf.

Contact Information:

The study is conducted on behalf of GSK by:

The Organization of Teratology Information Specialists (OTIS) Research Center

University of California

La Jolla

San Diego



Telephone: 877.311.8972


For more information, visit the MotherToBaby Website:


Target Enrolment:

Cohort 1 200 pregnancies
Cohort 2 300 pregnancies
Cohort 3 300 pregnancies

Study Start Date: November 2016

Estimated Completion Date: 2023

Additional Information: