Cohort Profile Update: the Rotterdam Periconceptional Cohort and embryonic and fetal measurements using 3D ultrasound and virtual reality techniques

For more than three decades, extensive translational research has identified strong associations between fetal growth and development and fetal programming of health and diseases in later life [Developmental Origins of Health and Disease (DOHAD) hypothesis].1,2 More recently, the focus of DOHAD research has shifted to the periconceptional period, defined as the time window of 14 weeks before up to 10 weeks after conception, thereby covering the vulnerable processes of gametogenesis, embryogenesis and initiation of placentation. During this period, numerous molecular and biological processes are initiated, such as epigenetic modification (e.g. genome-wide methylation) and also unique transcriptional and translational activities. The periconceptional period as such represents a critical and vulnerable time window for a diversity of exposures with potentially large effects during the entire prenatal as well as postnatal life course. So far significant associations have been detected between maternal and paternal periconceptional exposures, pregnancy outcome and non-communicable diseases over the entire life course and in later life.3–6 The Rotterdam Periconceptional Cohort (Predict study) was initiated because most birth cohorts start enrolment and data collection during the second half of pregnancy or at birth, thereby ignoring the periconceptional window and the first half of pregnancy.7 Within this cohort we have designed serial patient consultations, including ultrasound measurements starting in the embryonic period. Morphological parameters as well as early placentation are being studied using innovative virtual reality imaging techniques. The Predict study is designed as a tertiary hospital-based, prospective open birth cohort study, with a focus on three research areas: (i) determinants of maternal and paternal periconceptional health; (ii) reproductive performance, pregnancy course and outcome; and (iii) underlying molecular biological mechanisms, such as 1-carbon metabolism and epigenetics and also cardiovascular and inflammatory mechanisms. The strength of this open and ongoing cohort lies in the fact that the various outcomes within these three research areas are of equal significance for the periconceptional period. Hypothesis-driven specific outcome parameters are defined before initiation of new studies within the cohort. Only after approval of a new study proposal can the particular study be initiated within the cohort. The achieved output very much depends on the topic of (inter)national scientific research calls, and thus funding. The study started in November 2010 (after a pilot phase initiated in December 2009) and its ongoing cohort design serves as an infrastructure for embedding other subcohort studies, investigating research questions and measuring additive outcome parameters in more detail.7 All participants are recruited from the outpatient clinic of the Erasmus MC, University Medical Center, a Dutch tertiary referral centre for predominantly high risk pregnancies. Inclusion criteria are: (i) women (and their partner) should at least have reached the age of 18; (ii) proficiency in speaking and reading the Dutch language. Annually, about 2500 couples visit the Erasmus MC outpatient clinic for preconception or pregnancy consultation. The tertiary setting allows for a yearly capacity of first-trimester serial ultrasound measurements in at least 250 pregnancies. In total, 2950 couples have been included in the period between December 2009 and August 2018; 233 pregnancies from the preconceptional period up to 8 weeks of gestation were enrolled during the pilot phase (December 2009 and November 2010). A total of 2717 couples participated in this cohort between November 2010 and August 2018. Of these couples, 1891 women were included during the periconceptional period and 826 pregnancies ranging from 13 weeks of gestation until term. For the current profile update paper, it was decided to include all results until August 2018, since all participants had delivered by that time. During the pilot phase, women underwent weekly 3 D transvaginal ultrasound examinations between 6 + 0 and 12 + 6 weeks of gestational age and inclusion was required <8 weeks of gestation (Figure 1). Serial investigation during the first trimester included two-dimensional (2 D) and 3 D transvaginal ultrasound examinations at 7, 9 and 11 weeks of gestational age. The subcohorts of the Dream and Virtual Placenta study included additional 2 D and 3 D transabdominal ultrasound examinations at 22, 26 and 32 weeks of gestation (Figure 2). Flowchart of included participants from November 2010 until August 2018 (without the pilot study participants). GA, gestational age Flowchart of included participants from November 2010 until August 2018 (without the pilot study participants). GA, gestational age Study design of Predict Cohort; including all subcohorts. General investigations of all subcohorts during the preconception period, 1st, 2nd and 3rd trimester, postpartum period, including follow-up at 1 year after delivery are shown. PE, preeclampsia; FFQ, Food Frequency Questionnaire Study design of Predict Cohort; including all subcohorts. General investigations of all subcohorts during the preconception period, 1st, 2nd and 3rd trimester, postpartum period, including follow-up at 1 year after delivery are shown. PE, preeclampsia; FFQ, Food Frequency Questionnaire A more detailed description of the cohort is provided by the cohort profile article of Steegers-Theunissen et al.7 In short, women, and their partners, who are scheduled for a first prenatal visit at the outpatient clinic, are actively invited to participate (by means of an information brochure). Eligible couples undergo a standardized booking visit, in which height, weight, waist and hip circumference and systolic and diastolic blood pressure are determined. Before this booking visit, participants, including both women and their partners, are asked to fill out an extensive online questionnaire concerning both parental characteristics, medical (and obstetric) history, pre-pregnancy body mass index (BMI) and lifestyle behaviours. Moreover, a 196-item Food Frequency Questionnaire (FFQ) is completed for information about parental dietary patterns. Follow-up questionnaires are sent at 24 weeks of gestational age, around the expected delivery date and 1 year after actual delivery. Follow-up questionnaires collect information on health and environmental exposures and the course and outcome of pregnancy. One year after delivery, final information on general health of the offspring, including growth, congenital malformations and development is requested. Preconceptionally and/or during the first trimester, both maternal and paternal venous blood samples are collected. At birth, umbilical cord blood is collected and, depending on the subcohort, the placenta is sent for pathological examination. Table 1 shows the numbers and percentages of available questionnaires and samples that have been collected up until August 2018 (excluding the pilot phase). Data collection and general characteristics of the participants included between November 2010 and August 2018 General questionnaires General questionnaires SD, standard deviation; IVF, in vitro fertilization; ICSI, intracytoplasmic sperm injection; BMI, body mass index; PIH, pregnancy-induced hypertension; GA, gestational age. Update until August 2018, since all participants delivered and we could include the pregnancy outcome data in this manuscript. Data collection and general characteristics of the participants included between November 2010 and August 2018 General questionnaires General questionnaires SD, standard deviation; IVF, in vitro fertilization; ICSI, intracytoplasmic sperm injection; BMI, body mass index; PIH, pregnancy-induced hypertension; GA, gestational age. Update until August 2018, since all participants delivered and we could include the pregnancy outcome data in this manuscript. As mentioned previously, the Predict study serves as an infrastructure for embedding new subcohorts. The first subcohort study, the Dream study, focused on detailed markers of embryonic and fetal brain development in the first, second and third trimester of pregnancy and continuing into the neonatal period (N = 227).8–12 The second subcohort study, the Purple study, aimed at the occurrence of early-onset and late-onset preeclampsia. Placenta and umbilical cord (postpartum) pathological examination, umbilical cord cell populations and the tissue-specific epigenome of the placenta and newborn were studied (N = 448).13–15 The third subcohort study, the Virtual Placenta study, concentrated on placental growth and development starting as early as the first-trimester (N = 241).16 Ongoing subcohorts are the Virtual Pre-implantation Embryo study, focusing on (pre-implantation) embryonic growth and development from the preconception period onwards (N = 360, number until 1 January 2019, still ongoing) and the HAPPO study, concentrating on maternal haemodynamic parameters before and during pregnancy (N = 25, number until October 2019, still ongoing).17 In addition, intervention studies designed as survey and multicentre randomized controlled trials are conducted using the mHealth coaching platform Smarter Pregnancy to empower couples to adapt a healthier lifestyle from the periconceptional period onwards.18,19 Also pregnant women with or without their male partner could participate in the study.20,21 Over the past years, data have been collected on 233 (pilot phase study) and 2717 (Predict study) couples and their pregnancies. Data have been used in multiple published articles in which several associations between exposures and both periconceptional and pregnancy outcomes have been studied (Supplementary File 1, available as Supplementary data at IJE online). This cohort profile update paper not only represents an update of these results, but also provides description and discussion of our 3 D ultrasound and virtual reality measurement protocols. The results of the studies within the Predict cohort necessitated a re-evaluation and new strategies within the cohort. To optimize, further understand and unravel the potentials of maternal and paternal periconceptional health, an additional new study design of the original cohort is required. The new strategy and reason for the current update profile paper are aimed at studying the effects of an intervention on growth and development of the unborn child. Therefore, in 2021 the study will be extended with a nested randomized controlled trial, using a periconceptional blended lifestyle care approach in a specific high-risk population (BMI >25 kg/m²). Apart from the previous mentioned intervention, the design will be as the general observational cohort. The nested randomized controlled trial is considered the best design to show effectiveness, and has been developed to study the outcomes as defined for the cohort by integrating a blended lifestyle care approach into the current level of standardized health care.22 The study will be conducted during the periconceptional period in women at high risk of pregnancy complications and including their partners. The control group will receive standard care as also provided to the participants of the cohort according to local and national antenatal care protocols. The intervention group of high risk women will receive a combination of a personalized eHealth coaching programme for a period of 26 weeks [www.smarterpregnancy.co.uk] and a face-to-face counselling session with focus on lifestyle improvements. This approach allows for analyses of subgroups and associations between lifestyle changes and reproductive outcomes in the women, their male partners and their offspring. To gain further insight into fetal and placental development, 3 D ultrasound examinations at 24 and 32 weeks of gestation will additionally be performed among all participants. Due to a 10-year anniversary evaluation, new areas in the dataset will be explored. In ongoing both uncomplicated and complicated pregnancies (i.e. miscarriage, intra-uterine fetal death, congenital anomalies, hypertensive disorders, large for gestational age, fetal growth restriction and preterm birth), serial parameters have been collected. Unique data are available for analysis since collection was already initiated during the periconceptional period. Until now, data have been published of subsets of these pregnancies focusing on the ongoing uncomplicated pregnancy group. In the existing dataset, as well as in new subcohorts, unique areas of research will be explored, by studying determinants of maternal and paternal periconceptional health in association with reproductive performance, pregnancy course and outcome, as well as underlying molecular biological mechanisms, including cardiovascular and metabolic pathways, inflammation and epigenetic profiles. The Virtual Pre-implantation Embryo study investigates pre-implantation embryonic development using the EmbryoScope™, a time-lapse incubator providing a controlled culture environment and capturing comprehensive information on morphokinetics of the pre-implantation embryo. In animal models, the timing of embryonic developmental events has been shown to reflect embryonic metabolism and genetic integrity.23 The use of the EmbryoScope™ will enable us to further unravel the link between periconceptional parental exposures (such as obesity), in vitro environment, pre-implantation and post-implantation embryonic growth and development. In collaboration with the Biomedical Imaging Group of the Erasmus MC, new innovative research will use deployment of artificial intelligence (AI) to focus on fully automated analyses of 3 D ultrasound data, with the goal to develop a spatiotemporal 3 D ultrasound embryonic and fetal brain atlas. The new 3 D atlas will enable fully automated pattern recognition within the developing embryonic and fetal brain. The use of AI will enable more reliable, less time-consuming and more independent measurements of brain structures and allow for putting the development of the entire prenatal brain into perspective regarding different parental exposures as well as maternal, fetal and neonatal outcomes. The maternal environment and its cardiovascular system adaptation to pregnancy are crucial in the development of the embryo, the fetus and the placenta. The general aim of the Virtual Placenta study is to study periconceptional and (patho)physiological maternal cardiovascular and uterine vascular placental (adaptation) mechanisms that contribute to the origin of placenta-related pregnancy outcomes. Within this study, first-trimester reference values for longitudinal uterine vascular placental parameters will be determined using 3 D power Doppler ultrasound and virtual reality. To get more insight into vascular processes involved in in utero vascular placental development, placental parameters and embryonic growth trajectories, pregnancy outcome and periconceptional maternal vascular adaptation mechanisms will be studied. In addition to uterine vascular placental development studied using state-of-the-art 3 D ultrasound and virtual reality techniques, maternal haemodynamic parameters before and during pregnancy are studied in the HAPPO study. The HAPPO study investigates the haemodynamic adaptation of women to pregnancy by examination of the maternal macro-circulatory and micro-circulatory system and uterine vascular placental development in the preconception period, during pregnancy and 3 months after delivery. The main outcome measures are differences in maternal haemodynamic adaptation to pregnancy between women with and without placenta-related pregnancy complications. A more detailed description of the HAPPO study protocol has been published separately.17 Finally, we want to address Smarter pregnancy. This is an example of a platform that has been first studied in a research setting and is now being used in regular clinical care at our outpatient clinic [www.smarterpregnancy.co.uk].18,19 The platform has been incorporated in the administrative database of the Erasmus MC since 2019; so every health care professional can see when a woman and her partner were included in this platform, together with the outcome of the visit and future goals. With permission of the woman and her partner, the information is also incorporated in national clinical and epidemiological databases. Two-dimensional and 3 D transvaginal and transabdominal ultrasound examinations are performed and subsequently analysed offline. Embryonic and fetal structures of interest include strictly defined and clinically important biometric measurements and also novel biometric and volumetric parameters. 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