Supplementary Table 1. Variable Categorizations and Comparison of PRAMS and MES Questions

Supplementary table 1. Variable categorizations and comparison of PRAMS and MES questions. Variable (categorization) PRAMS MES Race/Ethnicity (In the U.S. it This variable is from the birth certificate and SD_Q06 Are you an Aboriginal person, that is, was categorized as black, white, is recoded categorically: black, white, other. First Nations, Métis or Inuit? or other whereas in Canada it 22. MOTHER’S RACE (Check one or more 1 Yes was categorized as aboriginal races to indicate what the mother considers 2 No ...... (Go to SD_R08) descent, or not of aboriginal herself to be) DK, ...... (Go to SD_R08) descent) Maternal age at delivery This variable was from the birth certificate The date of the birth of the mother (day, month (Maternal age was categorized as and was coded categorically before we and year) and the date of birth of her baby’s <20, 20-24, 25-34 and 35+ years received it into these categories:<17, 18-19, birth (day, month and year) were recorded, of age.) 20-24, 25-29, 30-34, 35-39, 40+ and were used to derive the mother’s age on the day of delivery. These questions were asked as part of the introductory sample screening process and do not appear in the published questionnaire. Previous premature birth 9. Was the baby just before your new one RH_Q07 Including the pregnancy with your (combined with variable below born more than 3 weeks before its due date? baby, how many pregnancies ended in a to be primiparous, multiparous No premature birth, that is, a baby born at less than with history of PTB, multiparous Yes 37 weeks of pregnancy? without history of PTB) We also have another birth certificate From this information we then used the number variable that was available for those states that was given to calculate the number of who had adopted the 2003 version of the birth previous preterm births. certificate, which measures a broader history of "previous preterm birth," and we use this variable in sensitivity analyses. Previous live births (combined 7. Before you got pregnant with your new RH_Q04 Including the birth of your baby, how with variable above to be baby, did you ever have any other babies who many times have you given birth to a live primiparous, multiparous with were born alive? No ≡ Go to Question 10, Yes baby? history of PTB, multiparous without history of PTB) Cesarean section (c-section vs. This variable is from birth certificate: LB_Q18 Did you have a vaginal or caesarean vaginal) D. Final route and method of delivery (Check birth for ^baby's name? one) 1 Vaginal □ Vaginal/Forceps □ Vaginal/Vacuum 2 Caesarean □ Cesarean DK, RF Income (Household income was 54. During the 12 months before your new WA_Q09 What is your best estimate of the categorized into approximate baby was born, what was your total total income, before taxes and deductions, of tertiles based on the most household income before taxes? Include all household members from all sources in the comparable cutpoints between your income, your husband’s or partner’s past 12 months? the U.S. and Canada datasets (< income, and any other income you may have Less than $10,000 20th percentile, 20th to 65th used. (All information will be kept private and $10,000 to less than $15,000 percentile, >65th percentile). will not affect any services you are now $15,000 to less than $20,000 Note: For exchange rates we can getting.) Check one answer $20,000 to less than $30,000 go here: Less than $10,000 $30,000 to less than $40,000 http://www.bankofcanada.ca/rate $10,000 to $14,999 $40,000 to less than $50,000 s/exchange/can-us-rate-lookup/) $15,000 to $19,999 $50,000 to less than $60,000 $20,000 to $24,999 $60,000 to less than $80,000 $25,000 to $34,999 $80,000 to less than $100,000 $35,000 to $49,999 $100,000 to less than $150,000 $50,000 or more $150,000 to less than $200,000 A small number of states were categorized $200,000 or more like this below: LESS THAN $ 8,000 $ 8,000 TO $ 9,999 $50,000 TO $74,999 $75,000 OR MORE Variable (categorization) PRAMS MES Stressful life events 31. This question is about things that may SE_Q02 In the 12 months before your baby (dichotomized as three or more have happened during the 12 months before was born a close family member was very sick events vs less than three) your new baby was born. For each item, and had to go into the hospital? y/n circle Y (Yes) if it happened to you or circle SE_Q03 In the 12 months before your baby N (No) if it did not. (It may help to use the was born you got separated or divorced from calendar.) your husband or partner? y/n No Yes SE_Q04 In the 12 months before your baby a. A close family member was very sick and was born you moved to a new address? y/n had to go into the hospital ...... N Y SE_Q05 In the 12 months before your baby b. I got separated or divorced from my was born you were homeless? y/n husband or partner ...... N Y SE_Q06 In the 12 months before your baby c. I moved to a new address ...... N Y was born your husband or partner lost his job? d. I was homeless ...... N Y y/n e. My husband or partner lost his job ...... N Y SE_Q07 In the 12 months before your baby f. I lost my job even though I wanted to go on was born you lost your job even though you working ...... N Y wanted to go on working? y/n g. I argued with my husband or partner more SE_Q08 In the 12 months before your baby than usual...... N Y was born you and your husband or partner h. My husband or partner said he didn’t want argued more than usual? y/n me to be pregnant ...... N Y SE_Q09 In the 12 months before your baby i. I had a lot of bills I couldn’t pay ...... N Y was born your husband or partner said he did j. I was in a physical fight ...... N Y not want you to be pregnant? y/n k. I or my husband or partner went to jail..N Y SE_Q10 In the 12 months before your baby l. Someone very close to me had a bad was born you had a lot of bills you couldn't problem with drinking or drugs ...... N Y pay? y/n m. Someone very close to me died …...... N Y SE_Q11 In the 12 months before your baby was born you were involved in a physical fight? y/n SE_Q12 In the 12 months before your baby was born you or your husband or partner went to jail or a detention centre? y/n SE_Q13 In the 12 months before your baby was born someone very close to you had a bad problem with drinking or drugs? y/n SE_Q14 In the 12 months before your baby was born someone very close to you died? y/n BMI (Pre-pregnancy BMI was 5. Just before you got pregnant with your HW_Q02A Just before your pregnancy, how calculated as weight in kg new baby, how much did you weigh? much did you weigh? divided by height in m2, and was [BOX] Pounds OR [BOX] Kilos categorized as underweight (BMI <18.5), normal weight 6. How tall are you without shoes? HW_Q01A How tall are you without shoes on? (18.5-24.9), overweight (25.0- [BOX] Feet [BOX] Inches 29.9), and obese (≥30.0).) OR [BOX] Centimeters smoke during last 3 months 26. In the last 3 months of your pregnancy, SM_Q07 During the last 3 months of your pregnancy (yes vs. no) how many cigarettes did you smoke on an pregnancy, did you smoke cigarettes daily, average day? (A pack has 20 cigarettes.) occasionally or not at all? 41 cigarettes or more Daily 21 to 40 cigarettes Occasionally 11 to 20 cigarettes Not at all 6 to 10 cigarettes 1 to 5 cigarettes Less than 1 cigarette None (0 cigarettes) Marital status Note: this This question was from the birth certificate: SD_Q16 What is your marital status? Are you? variable was not included in the MOTHER MARRIED? (At birth, conception, 01 Married final analysis as it was or any time between) 02 Living common law categorized differently in the 03 Widowed data that were available to us. 04 Separated 05 Divorced 06 Single, never married Variable (categorization) PRAMS MES DK, RF Preg intention Note: this 10. Thinking back to just before you got CB_Q02 Thinking back to just before you variable was not included in the pregnant with your new baby, how did you became pregnant, would you say that you final analysis (Categorized as feel about becoming pregnant? Check one wanted to be pregnant... sooner/then vs. later/not at all). answer Sooner I wanted to be pregnant sooner Later I wanted to be pregnant later Then I wanted to be pregnant then Not at all I didn’t want to be pregnant then or at any time in the future Barriers to prenatal care Barriers to prenatal care (coded as yes/no) – Barriers to prenatal care (coded as yes/no) – initiation Note: this variable was did she have at least one of the barriers below did she have at least one of the barriers below not included in the final analysis. to accessing prenatal care? to accessing prenatal care? (ategorized as yes vs. no). 17. Here is a list of problems some women PC_Q03 What prevented you from getting can have getting prenatal care. For each item, prenatal care as early as you wanted? circle Y (Yes) if it was a problem for you Doctor/ healthcare provider unavailable during your most recent pregnancy or circle N Doctor/ healthcare provider would not start (No) if it was not a problem or did not apply care earlier to you. Respondent didn't know she was pregnant No Yes Respondent didn't have child care a. I couldn’t get an appointment when I Respondent was too busy wanted one ...... N Y Respondent didn't have transportation b. I didn’t have enough money or insurance to Respondent couldn't take time off work pay for my visits ...... N Y Other - Specify c. I had no way to get to the clinic or doctor’s office ...... N Y d. I couldn’t take time off from work ...... N Y e. The doctor or my health plan would not start care as early as I wanted ...... N Y f. I didn’t have my Medicaid card ...... N Y g. I had no one to take care of my children ………..…………………………………..N Y h. I had too many other things going on....N Y i. I didn’t want anyone to know I was pregnant...... N Y j. Other ...... N Y Maternal Education Note: this This variable was from the birth certificate SD_Q12 Did you graduate from high school variable was not included in the and was categorized before we received it into (secondary school)? final analysis (categorized into these categories: 0-8 yrs, 9-11 yrs, 12 yrs, 13- 1 Yes whether the woman had or had 15 yrs, >= 16 yrs 2 No not graduated from high school). DK, RF Alcohol use Note: this variable 30a. During the last 3 months of your AL_Q03 After you realized you were pregnant, was not included in the final pregnancy, how many alcoholic drinks did how often did you drink alcoholic beverages? analysis (categorized as yes vs. you have in an average week? Was not drinking at the time/stopped drinking no). 14 drinks or more a week Less than once a month 7 to 13 drinks a week Once a month 4 to 6 drinks a week 2 to 3 times a month 1 to 3 drinks a week Once a week Less than 1 drink a week 2 to 3 times a week I didn’t drink then 4 to 6 times a week Everyday