Methods of linking mothers and infants using health plan data for studies of pregnancy outcomes

UMMS Affiliation

Meyers Primary Care Institute

Publication Date


Document Type



Pregnancy; Maternal Exposure; Pregnancy Outcome; Medical Record Linkage


Epidemiology | Health Services Administration | Health Services Research | Maternal and Child Health | Obstetrics and Gynecology | Pharmacy and Pharmaceutical Sciences | Women's Health


PURPOSE: Research on medication safety in pregnancy often utilizes health plan and birth certificate records. This study discusses methods used to link mothers with infants, a crucial step in such research.

METHODS: We describe how eight sites participating in the Medication Exposure in Pregnancy Risk Evaluation Program created linkages between deliveries, infants and birth certificates for the 2001-2007 birth cohorts. We describe linkage rates across sites, and for two sites, we compare the characteristics of populations linked using different methods.

RESULTS: Of 299 260 deliveries, 256 563 (86%; range by site, 74-99%) could be linked to infants using a deterministic algorithm. At two sites, using birth certificate data to augment mother-infant linkage increased the representation of mothers who were Hispanic or non-White, younger, Medicaid recipients, or had low educational level. A total of 236 460 (92%; range by site, 82-100%) deliveries could be linked to a birth certificate.

CONCLUSIONS: Tailored approaches enabled linking most deliveries to infants and to birth certificates, even when data systems differed. The methods used may affect the composition of the population identified. Linkages established with such methods can support sound pharmacoepidemiology studies of maternal drug exposure outside the context of a formal registry. Copyright (c) 2013 John Wiley and Sons, Ltd.


Medicaid, Birth certificates, Medical record linkage, Pharmacoepidemiology, Pregnancy outcome, Epidemiology

DOI of Published Version



Johnson KE, Beaton SJ, Andrade SE, Cheetham TC, Scott PE, Hammad TA, Dashevsky I, Cooper WO, Davis RL, Pawloski PA, Raebel MA, Smith DH, Toh S, Li DK, Haffenreffer K, Dublin S. Methods of linking mothers and infants using health plan data for studies of pregnancy outcomes. Pharmacoepidemiol Drug Saf. 2013 Jul;22(7):776-82. doi: 10.1002/pds.3443. Link to article on publisher's site

Journal/Book/Conference Title

Pharmacoepidemiology and drug safety

Related Resources

Link to Article in PubMed

PubMed ID