Mother & Child Health Initiative


Healthcare professionals (e.g. clinicians, laboratory professionals, midwives) depend on accurate reference standards (i.e. normative ranges or intervals) to interpret laboratory test results. Evidence-based reference intervals are lacking in pregnant individuals, which can compromise the quality of patient care during this critical stage of development. This new initiative aims to recruit 500 healthy pregnant individuals in the Greater Toronto Area and surrounding regions at each trimester as well as 1 to 3 months postpartum. This project is an extension of the CALIPER program. CALIPER is a leading contributor to the field of paediatric laboratory medicine and has published over 50 articles in peer-reviewed journals. The Mother & Child Health Initiative will apply the expertise of the CALIPER team to address similar gaps in pregnancy data. For more information on CALIPER, please visit the following resources:


Healthy pregnant individuals aged 18 to 40 years are eligible to take part in this initiative. We hold events at prenatal centres, midwife clinics, OBGYN clinics and other community centres in the Greater Toronto Area.

Who can participate?

Inclusion criteria

  • People aged 18 to 40 years
  • Healthy pregnancy (determined based on questionnaire responses)

Who cannot participate?

Exclusion criteria

  • People with a history of chronic illness or metabolic disease
  • People with prescribed medication over the past month
  • People with acute illness within the past 7 days

To participate, pregnant individuals are required to provide written informed consent, complete a short questionnaire and provide a blood sample. Demographic data collected includes previous and current health status, ethnicity, method of conception, and BMI parameters.

Sample collection and analysis

Fifteen mL of whole blood is collected in Serum Separator Tubes (SST, BD) and Lavender Tubes (KEDTA, BD) by trained phlebotomists using standardized conditions. Blood samples are centrifuged at 4000rpm for 10 minutes within eight hours of collection, aliquoted into 0.5 mL cryovials, and stored at –80 degrees Celsius.

Samples are analyzed in a timely manner for various laboratory parameters, including: liver enzymes, immune parameters, thyroid hormones, key chemistry, and haematology assays. All analytical methods are controlled according to manufacturers’ instructions via preventive maintenance and function checks, calibration, and quality control. All tests are subject to automated interference analysis for hemolysis, icterus, and turbidity.

Data analysis and statistics

Data is analyzed in accordance with guidelines published by the Clinical Laboratory Standards Institute (CLSI) in their report Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline – Third Edition (C28-A3). In addition to reference interval establishment, intra-individual changes are also assessed using analysis of variance.

  • Data is visually examined to determine appropriate gestational age partitions. Partitions are then statistically evaluated using the Harris and Boyd method.

  • Outliers are removed from each gestational partition using the Tukey or Adjusted Tukey method, based on data distribution.

  • Non-parametric or robust methods are used to determine specific reference intervals. For partitions with sample sizes >120, the non-parametric rank method is used, while the robust statistical methods are applied to partitions <120. The 90 per cent confidence intervals around the lower and upper reference limits are then calculated.

All statistical analysis is performed using MS Excel, SPSS, and R software. For a more detailed description of the methods we apply when calculating intervals, and then transferring those values to other instruments, refer to the CALIPER website.