3. Materials and Methods
3.1 Study design and data collection
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3.1 Study design and data collection
3.1.1 The Multinational Medication Use in Pregnancy Study
The Multinational Medication Use in Pregnancy Study is a cross-sectional, multinational, web-based study carried out within the period 1-Oct-2011 to 29-Feb-2012. Pregnant women at any gestational week and mothers of children less than one year of age were eligible to participate. Member countries of the ENTIS, OTIS in North America, MotherSafe in Australia and European institutions conducting public health research were invited to take part in the project. Of these, centers from 18 countries participated (Australia, Austria, Canada, Croatia, Finland, France, Iceland, Italy, Netherlands, Norway, Poland, Russia, Serbia, Slovenia, Sweden, Switzerland, United Kingdom and USA). Via OTIS we also collected data originating from some South and Central American countries.
The study was conducted in accordance to the CHERRIES statement.188
An electronic anonymous questionnaire administered by Quest Back (http://www.questback.com) was utilized to collect relevant data. The questionnaire was available and accessible on-line for a period of two months in each participating country within the main study period stated above. The study was an open survey; the questionnaire was open to the public via utilization of banners (invitations to participate in the study) on 2-3 national websites and/or social networks and/or pregnancy forums commonly visited and consulted by pregnant women and/or new mothers. The questionnaire was carefully designed to suit the internet administration approach. To improve the questionnaire completion rate we applied specific technical features such as multiple page design, routing of questions and progress indicator of completion. National websites were selected by the study coordinators in the country according to the number of daily users. Detailed information about recruitment tools utilized and internet penetration rates in each participating country is summarized in the Appendix 2 of paper I.
The questionnaire was first developed in Norwegian and English and then translated into the other relevant languages. The study coordinator in each participating country ensured quality, comprehension, and adaptation of the translated questionnaire to the relevant national context; for instance, the question about use of OTC medications during pregnancy was aided with examples of brand names of OTC drugs marketed in the specific
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country. Information about translated versions of the psychometric instruments used in the questionnaire is provided in section 3.5.
A pilot study was carried out in September 2011 in four countries (Finland, Italy, Norway and Sweden) (n=47) to ensure comprehension of the questionnaire, its suitability to the national context, and functionality of the electronic questionnaires. The pilot study elicited no major change to the questionnaire. Data from the pilot were not included in the study dataset.
Collected data were scrutinized for the presence of potential duplicates (based on reported country of residency, socio-demographic characteristics, date and exact time of questionnaire completion) but none were identified. Since the study was anonymous, no information about IP addresses was collected. The complete questionnaire is presented in Appendix 1 of paper I.
Studies I and III are based on the unique original version of the Multinational Medication Use in Pregnancy Study dataset.
3.1.2 The Norwegian Mother and Child Cohort Study
MoBa is a prospective population-based pregnancy cohort study conducted by the Norwegian Institute of Public Health.189 The aim of the MoBa is to identify causes of serious diseases in mothers and children. The cohort is dynamic and comprises more than 100,000 pregnancies from all over Norway recruited from 1999 to 2008.190 The recruitment began in Western Norway in 1999 and by the end of January 2006, a total of 50 out of 52 hospital and maternity units in Norway with more than 100 births annually, participated in the study. The women consented to participation in 40.6% of all pregnancies.189 The cohort now includes 114,500 children, 95,200 mothers and 75,200 fathers. Participants were recruited through a postal invitation in connection with a routine ultrasound examination offered to all pregnant women in Norway at 17-18 weeks of gestation. The invitation included an informed consent form, the first of six self±
administered questionnaires and an information brochure. There were no exclusion criteria.
The study is based on self-administered questionnaires. Participants completed three questionnaires during pregnancy: The first questionnaire (Q1) was completed around gestational weeks 13 to 17 (covering the period between six months prior to pregnancy and
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gestational week 18); the second questionnaire (Q2) was completed at gestational week 22 and covered information about dietary habits in pregnancy; the third questionnaire (Q3) (covering the second and part of the third trimester of pregnancy [until gestational week 29+]) was completed at gestational week 30. The fourth questionnaire (Q4) was distributed when the infant was six months old and comprised information on the last period of pregnancy (from the 30th gestational week until childbirth). Q1, Q3 and Q4 collected a wide range of information on socio-demographic characteristics, outcomes of previous pregnancies, medical history, maternal health, lifestyle habits, and medication exposures as well as other exposures during pregnancy.189 The questionnaires Q1, Q3 and Q4 are outlined in Appendix 1. The study participants also received, and are still receiving, additional questionnaires at 18 months, three years, five years, seven years, and by 2012, eight years postpartum. Among those who agreed to participate in the MoBa, the response rate was 95% for Q1, 92% for Q3, and 87% for Q4.189 Biological specimens have also been collected from both parents during pregnancy and postpartum and from the offspring.190,191
Updated versions of the original MoBa dataset are released for research purposes each year.
Study II is based on version 7 of the quality-assured data file including women who delivered between 1999 and 2009. Study IV is based on version 4 including women who delivered between 1999 and 2006.
3.1.3 The Medical Birth Registry of Norway
The MBRN was established in 1967 and encompasses all births in Norway. The registry is based on compulsory notification of all live births, stillbirths and induced abortions after gestational week 12 (after week 16 up to 2002).192,193 Information on maternal health prior to and during pregnancy, the course of pregnancy and pregnancy complications, delivery and postpartum complications and interventions, and the health of the neonate is available from standardized forms, as outlined in Appendix 2. These forms were filled in by midwives and obstetricians and/or gynecologists at each delivery and also include antepartum obstetric records that are completed by general practitioners, gynecologists, or midwives throughout the pregnancy. Medical conditions within the mother and/or child are coded according to the International Classification of Disease (ICD) and related health problems and using unique codes created by the MBRN.194
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