Table 1 Description of additional independent variables

Income Assistance

A woman was considered to have received income assistance if she was coded as having received income assistance anytime during the period of seven months prior to the month of the baby’s delivery to one month after the baby’s delivery (excludes: women living in First Nations communities, stillbirths, out of province births)

 Single Parent

A woman was considered a single (or lone) parent if she was identified as the sole primary care giver for the child on the Families First Screen.

 Married or Partnered

A woman giving birth was considered married/partnered if either a marriage was reported to Manitoba Health OR if according to the Families First Screen, she was not a single parent.

 Unknown marital status

A woman giving birth was considered to have an unknown marital status if the single parent question on the Families First Screen was left blank or no Families First Screen was done and there was no marriage reported to Manitoba Health.

Income quintile

Income quintiles were developed by assigning average household income from the 2006 Statistics Canada Census to dissemination areas and then ranking these from highest to lowest. Dissemination areas were then grouped into five groups or quintiles (1 being poorest and 5 being wealthiest). Each quintile contained approximately 20% of the population.

Diabetes

A woman was considered to have diabetes if in the three years prior to giving birth she had:

1) one or more hospitalizations with diagnosis code 250 (ICD–9–CM) or E10–E14 (ICD–10–CA) in any diagnosis field over three years of data OR

2) two or more physician claims with diagnosis code 250 over three years of data OR

3) one or more prescriptions for diabetic drugs – Insulins and Analogues (A10A); Blood Glucose Lowering Drugs excluding Insulin (A10BA02, A10BB01, A10BB02, A10BB03, A10BB09, A10BB12, A10BB31, A10BD03, A10BF01, A10BG02, A10BG03, A10BX02, A10BX03) over three years of data OR

4) one or more hospitalizations with gestational diabetes code in the gestation period (ICD–9–CM: 648.8, ICD–10–CA: O24)

Hypertension

A woman was considered to have hypertension if in the one year prior to giving birth she had:

1) at least one physician visit or one hospitalization (ICD–9–CM codes 401–405 or ICD–10–CA codes I10–I13, I15) OR

2) two or more prescriptions for hypertension drugs – Antihypertensives (C02AB01, C02AB02, C02AC01, C02CA04, C02CA05, C02DB02, C02DC01, C02KX01, C02LA01, C02LB01, G04CA03); Diuretics (C03AA03, C03BA04, C03BA11, C03CA01, C03CA02, C03CC01, C03DA01, C03DB01, C03DB02, C03EA01); Beta Blocking Agents (C07AA02, C07AA03, C07AA05, C07AA06, C07AA12, C07AB02, C07AB03, C07AB04, C07AB07, C07AG01, C07BA05, C07BA06, C07CA03, C07CB03); Calcium Channel Blockers (C08CA01, C08CA02, C08CA04, C08CA05, C08CA06, C08DA01, C08DB01); Agents Acting on the Renin–Angiotensin System (C09AA01, C09AA02, C09AA03, C09AA04, C09AA05, C09AA06, C09AA07, C09AA08, C09AA09, C09AA10, C09BA02, C09BA03, C09BA04, C09BA06, C09BA08, C09CA01, C09CA02, C09CA03, C09CA04, C09CA06, C09CA07, C09DA01, C09DA02, C09DA03, C09DA04, C09DA06, C09DA07) OR

3) At least one physician visit or one hospitalization in the gestation period (ICD–9–CM code 642 or ICD–10–CA codes O10–O16)

Antepartum hemorrhage

A woman was considered to have had an antepartum hemorrhage by the presence of:

1) One or more hospitalizations (ICD–9–CM 641, 641.0, 641.1, 641.2, 641.3, 641.8, 641.9; ICD 10– CA O44,O45, O46) in the gestation period indicating antepartum hemorrhage OR

2) One or more physician visits (ICD–9–CM 641, 641.0, 641.1, 641.2, 641.3, 641.8, 641.9) in the gestation period indicating antepartum hemorrhage.

Maternal Psychological distress

A woman was considered to have psychological distress if, in the two years prior to giving birth (or hospital discharge in case of a stillbirth), she had:

1) one or more hospitalizations with a diagnosis for depressive disorder, affective psychoses, neurotic depression, or adjustment reaction (ICD–9–CM codes 296.2–296.8, 300.4, 309, 311; ICD–10–CA codes F31, F32, F33, F341, F38.0, F38.1, F41.2, F43.1, F43.2, F43.8, F53.0, F93.0) OR

2) one or more physician visits with a diagnosis for depressive disorder, affective psychoses, or adjustment reaction (ICD–9–CM codes 296, 309, or 311) OR

3) one or more hospitalizations with a diagnosis for anxiety disorders (ICD–9–CM code 300; ICD–10–CA codes F32.0, F34.1, F40, F41, F42, F44, F45.0, F451, F452, F48, F68.0, F99) OR

4) one or more prescriptions for an antidepressant or mood stabilizer (ATC codes N03AB02, N03AB52, N03AF01, N05AN01, N06A) OR

5) one or more physician visits with a diagnosis for anxiety disorders (ICD–9–CM code 300) and one or more prescriptions for an antidepressant or mood stabilizer (ATC codes N03AB02, N03AB52, N03AF01, N05AN01, N06A) OR

6) one or more hospitalizations with a diagnosis for anxiety states, phobic disorders, or obsessive–compulsive disorders (ICD–9–CM codes 300.0, 300.2, 300.3; ICD–10–CA codes F40, F41.0, F41.1, F41.3, F41.8, F41.9, F42) OR

7) three or more physician visits with a diagnosis for anxiety disorders (ICD–9–CM code 300)

Short inter-pregnancy interval

A short inter-pregnancy interval was defined if the time between the last delivery and conception of the most recent pregnancy was less than 12 months, further divided into two categories: (i) of less than 180 days and (ii) 180–365 days. The date of the last delivery was determined from the Manitoba Health Insurance Registry while conception of the most recent pregnancy was determined from the Hospital Abstract Database.

Social isolation

A woman was considered to have social isolation (defined as lack of social support and/or isolation related to culture, language or geography) if this was identified on the Families First Screen.