Pregnant woman silhouette with data points background

Decoding Maternal Health Data: Are Birth Certificates and PRAMS Reliable?

Soraya Malik in Health & Wellness December 2025 • 4 min read.

"A deep dive into the accuracy of birth certificates and PRAMS in capturing maternal height and weight, and why it matters for public health."

Monitoring trends in pre-pregnancy obesity and gestational weight gain is a national priority, vital for understanding and addressing adverse health outcomes for both mothers and infants. Accurate data is the backbone of effective public health strategies, influencing everything from resource allocation to targeted interventions. Two key sources of this data in the United States are the revised birth certificate and the Pregnancy Risk Assessment Monitoring System (PRAMS).

The 2003 revision of the U.S. Standard Certificate of Live Birth included maternal height, pre-pregnancy weight, and delivery weight, enabling the calculation of pre-pregnancy BMI and gestational weight gain relative to Institute of Medicine (IOM) recommendations. PRAMS, a population-based surveillance system, gathers state-specific information on pregnancy-related characteristics, including self-reported height and pre-pregnancy weight.

But how reliable are these sources? A recent study dug deep into the quality of data collected from birth certificates and PRAMS questionnaires, comparing them against the gold standard of medical records. This article breaks down the study's findings, revealing the strengths and weaknesses of each data source, and highlighting the implications for maternal health research and surveillance.

Birth Certificates vs. PRAMS: Unpacking the Data Quality

Pregnant woman silhouette with data points background

The study, conducted in New York City and Vermont, compared data from birth certificates and PRAMS to medical records, looking at pre-pregnancy BMI, gestational weight gain, and component variables like height and weight. Researchers calculated mean differences and agreement rates, providing a clear picture of how well each source aligns with the gold standard.

Here’s a breakdown of the key findings:

Weight Variables: The mean differences for most maternal weight variables between the birth certificate or PRAMS and the medical record were less than 1 kg.
Pre-pregnancy BMI: The birth certificate classified similar proportions into pre-pregnancy BMI categories (agreement=89%, к=0.83) compared to the medical record. PRAMS slightly underestimated overweight and obesity (agreement=84%, к=0.73).
Gestational Weight Gain: The birth certificate overestimated gestational weight gain below recommendations and underestimated weight gain within recommendations (agreement=81%, к=0.69), compared to the medical record.
InconsistenciesAgreement varied by maternal and pregnancy-related characteristics.

These findings suggest that while both birth certificates and PRAMS provide valuable data, they aren't perfect. Understanding the nuances of each source is crucial for accurate interpretation and application.

Why Data Accuracy Matters for Maternal Health

The quality of maternal height and weight data directly impacts our ability to monitor trends in pre-pregnancy obesity and gestational weight gain. These trends are critical indicators of maternal and infant health, influencing the development of targeted interventions and resource allocation.

When using birth certificate or PRAMS data, be aware of potential misclassifications, particularly in pre-pregnancy BMI and gestational weight gain categories. Further research is needed to fully understand the impact of these misclassifications on epidemiological associations.

Improving the accuracy of delivery weight data on birth certificates could significantly enhance the reliability of gestational weight gain classifications. As electronic medical record systems become more integrated with birth registration systems, the potential for more accurate and standardized data collection increases. Continued evaluation and refinement of data collection methods are essential to ensure the best possible outcomes for mothers and their children.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1097/ede.0000000000000936, Alternate LINK

Title: Quality Of Maternal Height And Weight Data From The Revised Birth Certificate And Pregnancy Risk Assessment Monitoring System

Subject: Epidemiology

Journal: Epidemiology

Publisher: Ovid Technologies (Wolters Kluwer Health)

Authors: Nicholas P. Deputy, Andrea J. Sharma, Jennifer M. Bombard, Timothy L. Lash, Laura A. Schieve, Usha Ramakrishnan, Aryeh D. Stein, Michael Nyland-Funke, Pricila Mullachery, Erica Lee

Published: 2019-01-01

Everything You Need To Know

What are the key sources for collecting maternal health data?

The 2003 revision of the U.S. Standard Certificate of Live Birth includes maternal height, pre-pregnancy weight, and delivery weight. This enables the calculation of pre-pregnancy BMI and gestational weight gain relative to Institute of Medicine (IOM) recommendations. The Pregnancy Risk Assessment Monitoring System (PRAMS) gathers state-specific information on pregnancy-related characteristics, including self-reported height and pre-pregnancy weight. These two are key sources for maternal health data.

How does the study evaluate the reliability of the birth certificate and PRAMS?

Both the revised birth certificate and the Pregnancy Risk Assessment Monitoring System (PRAMS) are used to gather maternal health data. Researchers compare this data to medical records. The study found discrepancies between the data collected from birth certificates and PRAMS compared to medical records, specifically regarding weight variables, pre-pregnancy BMI, and gestational weight gain. The birth certificate and PRAMS give valuable data but are not perfect.

Why is accurate data on maternal health so important?

The accuracy of data from birth certificates and PRAMS is important because it directly affects our ability to monitor trends in pre-pregnancy obesity and gestational weight gain. Monitoring these trends is crucial for understanding and addressing adverse health outcomes for mothers and infants. Accurate data guides the development of targeted interventions and influences how resources are allocated in public health initiatives.

What were the key findings of the study comparing birth certificates and PRAMS?

The study, conducted in New York City and Vermont, compared data from birth certificates and PRAMS to medical records. Researchers looked at pre-pregnancy BMI, gestational weight gain, and component variables like height and weight. Mean differences and agreement rates were calculated to determine how well each source aligns with the medical records. The birth certificate classified similar proportions into pre-pregnancy BMI categories compared to the medical record, while PRAMS slightly underestimated overweight and obesity. The birth certificate overestimated gestational weight gain below recommendations and underestimated weight gain within recommendations.

What is the Pregnancy Risk Assessment Monitoring System (PRAMS) and what is its purpose?

The Pregnancy Risk Assessment Monitoring System (PRAMS) is a population-based surveillance system. It gathers state-specific information on pregnancy-related characteristics, including self-reported height and pre-pregnancy weight. The data collected through PRAMS, alongside data from birth certificates, helps in understanding maternal health trends, identifying areas for improvement, and informing public health strategies.