Background Large birth cohort studies are extremely valuable in assessing associations between early life exposures and long‐term outcomes. Establishing new birth cohorts is challenging due to declining participation rates. Online methods of data collection may increase feasibility, but have not been evaluated thoroughly. Objective The primary objective of the ongoing PRegnancy and Infant DEvelopment (PRIDE) Study is to identify exposures during pregnancy and in early life that may affect short‐term or long‐term health of mother and/or child. In this manuscript, we aimed to evaluate methods of recruitment and online data collection applied. Population Dutch women aged ≥18 years in early pregnancy. Design Prospective cohort study. Methods Initially, only prenatal care providers recruited participants, but alternative recruitment methods were added as a result of disappointing participation rates, including collaboration with “Moeders voor Moeders” (organisation that visits women in early pregnancy) and Facebook advertisements. Data on demographic characteristics, obstetric history, maternal health, life style factors, occupational exposures, nutrition, pregnancy complications, and infant outcomes are primarily collected through Web‐based questionnaires at multiple time points during and after pregnancy. Additional data collection components include paternal questionnaires, blood and saliva sampling, and linkage to medical records. Preliminary results By September 2019, 9573 women were included in the PRIDE Study, of which 1.3% completed paper‐based questionnaires. Mean age of the women analysed was 30.6 years, 71.1% had a high level of education, 57.2% were primiparae, and mean gestational age at enrolment was 9.9 (range 3, 37) weeks, with slight differences between recruitment methods. Pregnancy outcome was known for 89.8%. Retention rate at 6 months after the estimated date of delivery was estimated at 70%. Multiple validation studies conducted within the PRIDE Study indicated high data quality. Conclusion(s) Although challenging and time‐consuming, online methods for recruitment and data collection may enable the establishment of new birth cohort studies.

Noonan syndrome (NS) has been associated with an increased risk of lymphatic anomalies, with an estimated prevalence of 20%. The prevalence of lymphatic anomalies seems to differ between pathogenic variants. Therefore, this study aims to describe the clinical presentation, prevalence and genotype-phenotype correlations of lymphatic anomalies during life in patients with NS. This retrospective cohort study included patients (n = 115) who were clinically and genetically diagnosed with NS and visited the Noonan expertise Center of the Radboud University Medical Center between January 2015 and March 2021. Data on lymphatic anomalies during lifetime were obtained from medical records. Lymphatic anomalies most often presented as an increased nuchal translucency, chylothorax and/or lymphedema. Prenatal lymphatic anomalies increased the risk of lymphatic anomalies during infancy (OR 4.9, 95% CI 1.7-14.6). The lifetime prevalence of lymphatic anomalies was 37%.Genotype-phenotype correlations showed an especially high prevalence of lymphatic anomalies during infancy and childhood in patients with a pathogenic SOS2 variant (p = 0.03 and p < 0.01, respectively). This study shows that patients with NS have a high predisposition for developing lymphatic anomalies during life. Especially patients with prenatal lymphatic anomalies have an increased risk of lymphatic anomalies during infancy. Genotype-phenotype correlations were found in pathogenic variants in SOS2.