Data and Impact
Core PELL data link vital records (birth certificate or fetal death certificate data) with the maternal hospitalization for delivery records, and in the case of a live birth with the infant’s birth hospitalization records. To this core, PELL links administrative longitudinal records for both mother and infant for hospitalizations, emergency department visits and observational stays (Casemix data), as well as death records for mother and infant. Additional data are then linked including from the Massachusetts Birth Defects Registry (MBDR), Universal Newborn Hearing Screening (UNHS) programmatic data, Early Intervention (EI) programmatic data, and the Pregnancy Risk Assessment Monitoring System (PRAMS) survey data. PELL data can also be linked to Massachusetts Cancer Registry (MCR) data and additional data sources on a project-specific basis. PELL includes records from 1998 through 2023 and are updated yearly.
PELL Data Sources
PELL has five major sources of data:
- Birth Certificate (BC) and Fetal Death Certificate (FD)
- Hospital Discharge
- Emergency Department
- Observational Stay
- Programmatic Data
Learn more about our PELL data sources.
Currently, PELL data do not include outpatient or clinical records or pharmacy records. PELL anticipates incorporating data from the All-Payer Claims Database (APCD) and from MassHealth (Medicaid) by summer 2027.
PELL includes records from 1998 through 2023 and are updated yearly.
Number of total mothers and repeat mothers in PELL from 1998-2023
| Mothers | Linked BCFD records | All BCFD records |
|---|---|---|
| Total mothers | 1,147,534 | 1,173,008 |
| Repeat Mothers | 550,246 | 566,227 |
Number of deliveries for repeat mothers who had their first birth in PELL from 1998-2023
| Number of deliveries | Repeat mothers who had their first birth in PELL (1998-2023) |
|---|---|
| 2 | 345,465 |
| 3 | 108,863 |
| 4 | 25,081 |
| 5 | 5,490 |
| 6 | 1,659 |
| 7 | 514 |
| 8 | 194 |
| 9 | 81 |
| 10 | 26 |
| 11 | 13 |
| 12 | 4 |
| 13 | 3 |
| Total | 487,393 |
For years 1998-2023 inclusive, PELL has linked 99.6% of all births occurring in a MA hospital.
Percentage of births PELL linked from 1998-2023
| Birth Records | N | % |
|---|---|---|
| Total live births | 1,984,476 | 97.3 |
| Live Births occurring in MA | 1,953,623 | 98.8 |
| Live births occurring in a MA hospital | 1,937,420 | 99.6 |
Frequently Asked Questions
How to request PELL data?
PELL data require an application through our IRB using what we refer to as a 24A. Please see the IRB applications walk-through for that process.
If you are interested in applying for PELL data, we encourage you to set up a time to discuss with us before submitting an IRB application. Please reach out to the contact below.
Is there a cost to use PELL data?
We waive fees for students. For established researchers, our fees are based on the complexity of the work, and the timing and nature of the grant. Please contact us for more information.
How long does it take to obtain PELL data?
After submission, there may be several months before the IRB review. After the initial IRB review, the length of time for approval and obtaining data will depend on how many revisions are needed for IRB and what other projects the PELL programmers have in queue. Please plan on several months after applying.
Reports and Publications
Selected Publications Using PELL:
- Declercq ER, et al. (2025). Relationship Between Maternal Death and Infant Outcomes in Massachusetts (PELL). Obstetrics & Gynecology
- Declercq ER, et al. (2024). Emergency Care Use During Pregnancy and Severe Maternal Morbidity. JAMA Network Open
- Diop H, et al. (2024). Leveraging a Longitudinally Linked Dataset to Assess Maternal and Infant Outcomes (PELL). Women's Health Issues
- Osei-Poku GK, et al. (2024). Delivery at an inadequate level of maternal care is associated with severe maternal morbidity. American Journal of Obstetrics and Gynecology
- Khalili R, et al. (2024). Multiple prenatal exposures and acute-care clinical encounters for asthma (PELL cohort). American Journal of Epidemiology
- Declercq ER, et al. (2023). Prior Hospitalization, Severe Maternal Morbidity, and Risk of Readmission after Delivery. Obstet Gynecol
- Declercq ER, et al. (2022). Using Longitudinally Linked Data to Measure Severe Maternal Morbidity. Obstetrics & Gynecology
- Stern JE, et al. (2022). Assisted Reproductive Technology or Infertility: What Underlies Adverse Outcomes? Lessons from MOSART. F&S Reviews
- Diop H, et al. (2022). Trends and inequities in severe maternal morbidity in Massachusetts, 1998–2018. PLOS ONE
- Somerville, NJ et al. (2019). Obstetric Comorbidity and Severe Maternal Morbidity at Delivery: Massachusetts PELL 1998-2013. Maternal and Child Health Journal
- Mitra M, et al. (2018). Antenatal Hospitalization Among U.S. Women With Intellectual Disabilities (using MA PELL). American Journal of Preventive Medicine
- Harvey EM, et al. (2018). Severe Maternal Morbidity at Delivery and Risk of Hospital Readmission. Obstetrics & Gynecology
- Clements KM, et al. (2016). Birth characteristics associated with early intervention referral (PELL 1998-2000). Maternal and Child Health Journal
- Luke B, et al (2016). Birth Outcomes by Infertility Treatment: Analyses of the Population-Based Cohort Massachusetts Outcomes Study of Assisted Reproductive Technologies (MOSART). Journal of Reproductive Medicine
- Mitra M, et al. (2015). Pregnancy Outcomes among Women with Intellectual and Developmental Disabilities (PELL 1998-2010). BJOG/other
- Declercq ER, et al. (2015). Perinatal outcomes associated with assisted reproductive technology: the Massachusetts Outcomes Study of Assisted Reproductive Technologies (MOSART). Fertility and Sterility
- Luke B, et al (2015). Birth Outcomes by Infertility Diagnosis: Analyses of the Massachusetts Outcomes Study of Assisted Reproductive Technologies (MOSART). Journal of Reproductive Medicine