3.4.1 Screening interview
A short telephone screening interview was conducted with potential study participants to gather information (e.g. women’s date of birth, residential address, LMP, pregnancy status, pregnancy-related medication use) that was necessary to establish eligibility for RFTS study. If a woman was deemed eligible to participate in the study and she agreed to participate in RFTS, additional information was collected and an
endovaginal ultrasound was scheduled.
3.4.2 Participant consent
The RFTS research team employed a vigorous consent process to ensure that all study protocols was explained thoroughly and that all potential study participants understood all parts of the study activities. All study participants provided a signed consent prior to their first trimester ultrasound or participating in any study activities.
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3.4.3 Monetary and non-monetary participant incentives
Study participants were eligible to receive numerous incentives from the study. The amount of incentives varies depending on the type of study activity completed by each participant in the main study and/or in one of the sub-studies. Incentives included six free pregnancy test kits for women who enrolled into the study while trying to conceive, one free endovaginal ultrasound to all newly pregnant women, and monetary incentives in varying amount for the completion of one and both telephone interviews ($10 for baseline or $20 for modified baseline interview and $10 for follow-up or modified follow-up interview). An additional $10 was given to women who completed all study activities in the main study.
3.4.4 First trimester endovaginal ultrasound
First trimester endovaginal ultrasounds were conducted around eight weeks’ gestation (median gestational age at ultrasound=9.3 weeks) by ARDMS® certified clinical sonographers, using state-of-the-art ultrasound technology. All clinical sonographers were required to attend study-specific training and a trained study staff reviewed all data collection forms and still images prior to data entry. We collected measurements on the gestational sac, yolk sac, fetal pole, and fetal heart rate for use in clinical pregnancy dating.
3.4.5 Study telephone interviews
Some sociodemographic information (e.g. maternal age, mother’s highest
educational attainment, maternal race) were obtained during the screening interview. As part of the study activities, participants were asked to complete two telephone interviews
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that took place at two different time intervals in the course of the study. The baseline interview took place around one to two weeks after the screening interview and no later than 16 completed weeks’ gestation. This interview ascertained information on a range of topics such as:
Employment history
Health behaviors (water, alcohol and caffeine consumption, tobacco and illicit drug use, physical activity, and time in pool, hot tubs, and Jacuzzi) Water exposure characteristics
Current and previous reproductive histories (menstrual history, previous pregnancy history, time to conception, NVP, vaginal bleeding, infections, diabetes, medications taken to prevent pregnancy complications, and prenatal care)
Physical and sexual violence
Vitamin and mineral supplement use
Other social, household, and income information.
Participants were contacted between 22 to 26 weeks of their pregnancy for the follow-up telephone interview. This interview gathered additional information on the following topics:
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Current and past pregnancy and medical histories (diseases and injuries, surgical procedures, fever, and other health problems)
Pregnancy-related symptoms and information regarding prenatal care and delivery choices, and partner information.
Paternal information (age, race/ethnicity, education)
Study participants who had been identified as having pregnancy losses during either phase of the telephone interviews were asked to complete the modified version of the baseline or follow-up interview. The modified interviews ascertained identical
information as those in the “regular” interviews, but the language of the modified version took into account the sensitivity of the recent pregnancy loss. Figure 6 shows a flow diagram of RFTS study activities.83
Flow Diagram of Study Activities
Medical records Ultrasound abstraction
Baseline Follow-up
Weeks EGA/ 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Figure 6. Diagram of study activities, Right from the Start (2000-2004) *Adapted from AwwaRF report (Savitz et al., 2005)
IDEAL TIME FRAMES AND DEADLINES FOR ULTRASOUNDS AND CATI All Participants
First Trimester Ultrasound ideal time: 6 2/7 – 7 5/7 weeks; no later than 14 0/7 weeks Baseline CATI: preferably within 2 weeks of enrolling and no later than 16 0/7 weeks Follow-up CATI: 20 0/7 – 25 0/7 weeks
cut off for enrollment 12 6/7 weeks
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3.4.6 Medical record reviews and vital record linkages
Participants’ medical records were reviewed and relevant information was abstracted at the end of pregnancy, whether it resulted in a loss or in a live birth.
Information such as first day of the LMP, gestational age at delivery, pregnancy outcome, and other maternal demographic status from the medical chart abstraction was used to clarify discordance and to supplement the data collected during the telephone interviews. Additionally, vital and fetal death records were linked with existing participant data to confirm and/or to provide supplemental information on pregnancy outcomes. Infant’s birthweight, date of birth, and gender were key pieces of information abstracted from the vital records and similar information on the infant was obtained from the fetal death records.
Because of the comprehensive nature of RFTS, multiple sources including participant self-report, vital records, and medical records, were used to gather participant and pregnancy-related information; information collected such as pregnancy outcome and pregnancy outcome date, abstracted data from medical records took precedence over data from vital records, which took precedence over self-reported data.
3.5 Collection of NVP information