RESUMO
The National Children's Study (NCS) Harris County, Texas Study Center participated in the NCS Provider Based Sampling (PBS) substudy of the NCS Vanguard Phase pilot. As part of the hospital-based birth cohort component of the PBS substudy, we conducted a secondary data analysis to evaluate the proportion of postpartum women who consented to future biospecimen collection alone and to both future collection and use of residual birth biospecimens. In phase 1, 32 postpartum women at one hospital were asked to consent only to maternal future biospecimen collection. In phase 2, 40 other postpartum women from the same hospital were asked for an additional consent to use residual clinical biospecimens from the birth event that otherwise would be discarded, including cord blood and maternal blood and urine. Among 103 eligible women, a total of 72 participated. They were 28.3 ± 5.9 years old on average; 58 % were Hispanic; 63 % consented in English, and 37 % in Spanish; 39 % had some college education; 42 % were married; 60 % had an annual family income <$30,000; and 51 % were employed. In phase 1, 59 % consented to future biospecimen collection, and in phase 2, 95 % consented to both future collection and use of at least one residual birth biospecimen, with a difference between phases of 36 % [95 % CI 17-54 %]. Demographic characteristics did not differ among those who did and did not consent. Postpartum women were significantly more likely to grant consent for use of future and residual hospital-obtained biospecimens than future biospecimen collection alone.
RESUMO
OBJECTIVE: In 2010, the National Children's Study launched 3 alternative recruitment methods to test possible improvements in efficiency compared with traditional household-based recruitment and participant enrollment. In 2012, a fourth method, provider-based sampling (PBS), tested a probability-based sampling of prenatal provider locations supplemented by a second cohort of neonates born at a convenience sample of maternity hospitals. METHODS: From a sampling frame of 472 prenatal care provider locations and 59 maternity hospitals, 49 provider and 7 hospital locations within or just outside 3 counties participated in study recruitment. During first prenatal care visits or immediately postdelivery at these locations, face-to-face contact was used to screen and recruit eligible women. RESULTS: Of 1450 screened women, 1270 were eligible. Consent rates at prenatal provider locations (62%-74% by county) were similar to those at birth locations (64%-77% by county). During 6 field months, 3 study centers enrolled a total prenatal cohort of 530 women (the majority in the first trimester) and during 2 months enrolled a birth cohort of an additional 320 mother-newborn dyads. As personnel became experienced in the field, the time required to enroll a woman in the prenatal cohort declined from up to 200 hours to 50 to 100 hours per woman recruited. CONCLUSIONS: We demonstrated that PBS was feasible and operationally efficient in recruiting a representative cohort of newborns from 3 diverse US counties. Our findings suggest that PBS is a practical approach to recruit large pregnancy and birth cohorts across the United States.