For Researchers

The Ontario Birth Study (OBS) is a research platform developed by the Lunenfeld-Tanenbaum Research Institute and Mount Sinai Hospital (MSH) with support from Ontario Institute of Cancer Research (OICR) and the Fraser Mustard Institute for Human Development at the University of Toronto.

The Ontario Birth Study is an open longitudinal pregnancy cohort designed to serve as a platform for research on pregnancy complications, maternal and infant health, and, ultimately, to assemble a cohort for future studies on the developmental origins of health and disease. One of the goals of the OBS is to streamline research, reducing the burden of research on both clinical care and patients, while increasing research opportunities (lower cost, increased feasibility, and data availability) and enhancing clinical care.

See below for: Protocol | Lifestyle Questionnaires | Diet Questionnaire | The Biological Samples | The Clinical Data


Pregnant women are approached by OBS staff at their first ultrasound or prenatal visit at Mount Sinai Hospital and St. Michael’s Hospital obstetrics clinics. Subjects are recruited based on the following criteria:

Inclusion criteria

  • Pregnant women less than 17 weeks gestational age
  • At least 18 years of age
  • English speaking
  • Delivering at an OBS Hospital
  • Antenatal care at an OBS Hospital

Exclusion criteria

  • Non-viable fetus
  • Unable to provide informed consent
  • Known significant abnormalities

The consent obtained from all women covers questionnaire data, biospecimens, ultrasounds, and access to clinical records. As outlined in table 1, OBS participants are asked to complete four questionnaires: three lifestyle questionnaires and the Canadian Diet History Questionnaire II*Web. The scheduled collection of biospecimens, including maternal blood, infant blood spot cards, and vaginal swabs, is also shown in the table.

Table 1. Ontario Birth Study Data Collection Timeline

Time of your routine visitBlood workVaginal SwabsLifestyle QuestionnaireDiet QuestionnaireApproximate Time
Week 11-1430-40 cc2-4 swabs*✔ (LSQ1)-45 min
Week 16 30-40 cc--45 min
Week 2830-40 cc-✔ (LSQ2)-30 min
Week 34-38-2 swabs--10 min
Delivery30 cc;
Infant blood spot card
---10 min
6 weeks after Delivery--✔ (LSQ3)-30 min

*Women with a previous preterm delivery will be asked to provide 2 additional swabs (for a total of 4) at their first vaginal swab collection

Lifestyle Questionnaires

Women enrolled complete three lifestyle questionnaires using Research Electronic Data Capture (REDCap). Data collection fields are harmonized with the Better Outcomes Registry and Network (BORN). Some examples of the available data are provided below.

Table 2. Summary of maternal OBS survey instruments by timing of questionnaires

Timing of Questions
TopicDetailed items12-16 wks GA28-32 wks GA6-10 wks Postpartum
Demographic info and family characteristicsDate of birthX
Marital statusXXX
Details about FatherX
Mother’s siblingsX
AnthropometryRight/left handedX
Ability to standX
Weight (current and usual)XXX
Weight loss and controlXX
Health StatusSelf-reported healthXXX
Last check-up and dentalX
Sexual orientationX
Sexual partnersX
Bowel movementX
Oral HealthLast dental visit, gum disease & dental problems during pregnancyX
Menstrual HistoryAge at first periodX
Women’s health historyContraceptive useX
Sexual activityX
Uterine fibroids or defect
Screening MammogramX
Pap smear, cervical biopsyXX
Colorectal cancer screening
Current PregnancyLast menstrual periodX
When did you knowX
Feelings about pregnancyX
Intention to raise childX
Fertility treatmentDrugs, procedures, cost, elapsed timeX
Health during pregnancyBleeding, nausea, swellingXX
Fever & other infectionsX
Pregnancy conditionsX
X-rays, vaccinesX
Bed restX
Previous PregnanciesMothers age, father, fertility treatments, multiples, pregnancy conditions, outcome, birthweight, gestational age, delivery type, child death, breastfeedingX
Other childrenAdopted, foster, otherX
Personal medical historyList of conditions from OHS (predominately chronic diseases and cancer)X
Family health historyList of conditions for parents, siblings and previous childrenX
Mother’s own birthBirth weight, gestational ageX
MedicationPrescription and non-prescriptionXX
Vitamins, supplementsBefore and during pregnancyXXX
Fiber supplementsXX
Smoking and tobacco productsBefore pregnancy, during pregnancy, Other tobacco productsXXX
Environmental tobacco exposureBefore and during pregnancy at home, work and socialXX
Physical ActivityVigorous and moderate activity before and during pregnancy;XX
Sedentary activityXX
SleepDuration at night and day, disrupted breathing, snoringXX
Infant sleepX
Sunlight & skin typeSkin response to sunX
Sunbed useXX
AlcoholBefore and during pregnancy, type of alcohol, binge drinkingXXX
Food intakeVegetables, fruit, juiceX
Food insecurityX
Dietary restrictionsX
Emotional HealthDepression (DHQ-2 item)XXX
Anxiety (GAD-2 item)XXX
Depression (EPDS)XX
Anxiety (STAI-SF)XX
Perceived stress (4-item)XXX
Attachment (Bartholomew Horowitz)XX
Intimate partner violence (WAST)X
Adverse Childhood Experiences (ACE)X
Childbearing AttitudesXXX
Pregnancy Experiences ScaleX
BackgroundEthnicity and CountryX
WorkWork status, Job descriptionXXX
Occupational exposuresShift workXX
Chemical exposuresX
ResidenceLength of time lived thereX
IncomeHousehold incomeX
Number of people in homeXXX
Number of roomsXX
Owning house and carX
Environmental exposuresPets, pesticides, proximity to farm, busy roads, chemical dumpX
Questions about the baby’s biologic fatherAge, siblings/twin, adopted, education, height, weight, alcohol, smoking, ethnicity, left/right handed, restricted diet, sexual partners & infectionsX
Other QuestionsPermission to contact family members (mothers and baby’s father)XX
Name of pediatrician or family doctorXX
Labour and deliveryType of delivery, hospitalizationX
Infant HealthMedication useX
General healthX
Infant feedingIntention to breastfeedX
Formula typeX
Vitamin useX
CryingCrying Patterns QuestionnaireX

Diet Questionnaire

The web-based Canadian Diet History Questionnaire II*Web queries the participant’s diet over the past month. The questionnaire asks questions about Canadian-specific types, brands, and proportions of food. Based on questionnaire answers, the daily nutrient intake (e.g., total fat, total calorie intake, other vitamins and minerals) is then calculated.

The Biological Samples

Biospecimens are collected and processed at the Mount Sinai Hospital’s Biospecimen Repository and Processing Lab. Collection of placentas is done through the Mount Sinai Hospital’s Biobank. The collection of biological samples includes:

Maternal Blood

  • maternal DNA
  • leukocytes
  • plasma
  • serum

Infant Blood Spot Cards

  • infant DNA

Vaginal Swabs

  • bacterial DNA
  • cytokines

The Clinical Data

Additional data collected from the antenatal records and hospital medical charts are abstracted and entered into Medidata RAVE, an electronic data capture and storage platform, housed at the Applied Health Research Centre. Some of the available data includes:

Routine Demographic

  • age
  • height
  • weight

Medical History and Pregnancy Obstetrical History

  • medications
  • gravidity
  • parity

Current Pregnancy

  • blood pressure
  • blood work
  • urine test
  • ultrasound reports
  • interventions
  • labour details

Infant Assessment

  • gestational age
  • birth weight
  • gender