Three Generations Study (3Gs)

Lab Collaboration

Analysis of persistent environmental chemicals in archived samples from pregnant women in the 1960s and recent samples from their now-adult daughters in a study examining the risk of breast cancer and other diseases affecting women 

Logo for study shows outline of three female heads, a girl, a woman, an elderly woman and the number 3

The Three Generations Study (3Gs) is a follow-up study of contemporary women whose mothers enrolled in the Child Health and Development Studies (CHDS) between 1959 and 1967. During that time, more than 15,000 families in the Kaiser Permanente Health Plan joined the CHDS. These landmark studies have greatly advanced our knowledge about pregnancy, childbirth, and child development. As CHDS children have become adults and started their own families, follow-up studies, including the 3Gs study, are looking at other health outcomes such as cancer and heart disease.

The purpose of the 3Gs study is to look at causes of breast cancer and other diseases affecting women that may pass from one generation to the next and to look for associations between levels of environmental chemicals and risks of these diseases. As part of the 3Gs study, Biomonitoring California laboratories are measuring persistent environmental chemicals in blood samples obtained from the CHDS mothers during their pregnancies in the 1960s and their now-adult daughters in 2012-2013.  These data on levels of chemicals in two generations of women are being used for ground-breaking studies on:

  • The relationship between in utero chemical exposures and the risk of daughters’ breast cancer and other outcomes.
  • Differences in exposures to environmental chemicals across two generations of women.
  • The impact of results communication on actions that women might take to reduce exposures. 

The measurements of chemicals in these historic pregnancy samples, together with those measured in contemporary samples, are providing a picture of selected chemical exposures in Northern California women over two generations.  In addition, information is being collected on the children of the now-adult daughters, so that the third generation can be included in future studies.

This research is co-funded by the California Breast Cancer Research Program and the Breast Cancer Research and Environment Program, a joint effort of the National Institute of Environmental Health Sciences and the National Cancer Institute.

Project Type: 

Laboratory collaboration

Project Status: 



Mothers (n= 450; samples obtained during their pregnancies in the 1960s) and their now adult daughters (n=300; samples obtained in 2012-2013)

Sample Collection Date: 

1960 to 2013

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