Data Collection

Measurements in the prenatal phase of the study were conducted in two well-equipped research centers in the study area, with a close collaboration with midwives and hospitals. Data collection in the prenatal phase included:

• Physical examinations: these were planned at each visit in early pregnancy, mid-pregnancy and late pregnancy and included height, weight and blood pressure measurements of both parents.
• Questionnaires: mothers received four postal questionnaires and father received one postal questionnaire in the prenatal phase. Topics in these questionnaires varied from medical and family history to diet and from life style habits to educational level.
• Fetal ultrasound examinations: these were performed at each prenatal visit. The ultrasound examinations were used for both establishing gestational age and assessing fetal growth patterns.
• Biological samples: blood samples were collected in early and mid-pregnancy, at birth and cord blood at delivery. Urine samples of mothers had been collected and are used for measurement of several environmental exposures, metabolites and pesticides.

In the preschool period, detailed measurements were conducted in a dedicated research center in the Erasmus Medical Center - Sophia Children’s Hospital and routine care data were collected in five hospitals and sixteen child health centers located in this area. Data collection in this phase included:

• Home visit: at the age of 3 months, home visits were performed to assess neuromotor development.
• Physical examinations: information about growth (length (height), weight, head circumference) is collected at each visit to the routine child health centers in the study area using standardized procedures.
• Questionnaires: during the preschool period, mothers received 8 questionnaires and fathers received 1 questionnaire.
• Hands on assessments and observations in a subgroup: during the preschool period, children participating in the subgroup studies have been invited six times to a dedicated research center. Measurements at these visits included physical examinations and ultrasound examinations of brain structures, cardiac and kidney structures and abdominal fat. Also observations of parent-child interaction and behavior and biological materials have been collected, including nasal swabs, salivary samples and blood samples.

During Focus at 9, we again invited all participating children from the age of 9 years onwards, and their mothers to the Generation R research center. Linking the data from nine year olds to the data already collected during pregnancy and the first years after birth, gives an unique picture of the growth, development and health until the age of ten years. The first ten years of life are without a doubt the most vulnerable and most important years of life.
In this research phase, we continue with hands on measurements, behavioral observations and biological sample collection. The measurements are focused on asthma and allergy, behavior and motor development, eyesight and hearing, growth, tooth and jaw development, and heart growth and function.

In Focus at 9 we also made MRI scans of all participating children in order to examine brain, lungs and the cardiovascular system. The MRI scans were performed in two 30-minute sessions.  The MRI examinations were carried out in a specially designed child-friendly MRI research center in the Sophia Children's Hospital.

In Focus at 13, all Generation R children around the age of 13 were re-invited to assess their health and the various aspects of growth and development associated with puberty. In addition to our previous research tests performed at our facility, we introduced new tests and techniques in this phase to evaluate the health and development of this age group. A stress test on a bicycle, a skin color analysis with spectrophotometric technique along with the sampling of bacterial skin flora and dental plaque were performed. Cognitive tests were performed on a computer as games and tasks and abdominal fat was measured with ultrasound. For mothers an endothelial function test was performed to study their perfusion.

In addition, in Focus at 13, we again made MRI scans of all participating children to examine the brain, heart and the hip at our dedicated research facility in the Erasmus University Medical center-Sophia Children’s Hospital.