NCS Vanguard Study Recruitment Summary by Recruitment Strategy, 2009 to 2014

Recruitment StrategyTotal
Recruitment period: beginning with first woman and ending with last newborn enrolledJanuary 2009–December 2012November 2010–December 2012November 2010–December 2012November 2010–December 2012December 2012–March 2014
Total months of recruiting women (activea recruitment months)36 (18)16 (13)16 (13)16 (13)7 (7)
No. of study locations7101010340
Women identified for screening35 72627 84019 3473717325689 886
Women screened for pregnancy30 96021 39917 1942998145374 004
Women eligibleb for enrollment3164248227811470126811 165
Women enrolled (pregnant or preconceptional)19961647225611728507921
 Women pregnant at enrollment or who became pregnant during follow-up15921161155610698506228
 Enrolled pregnant women who enrolled infants1297102213709987335420
Newborn children enrolledc14091039139510217445608
  • —, not applicable.

  • a Active recruitment refers to study center staffs identifying, screening, and recruiting potential study participants through participant outreach and engagements whereas passive recruitment refers mostly to the follow-up of preconceptional women to determine pregnancy status and enrollment of referred pregnant women.

  • b Eligibility criteria differentiated by strategy but common to the first 4 are women age 18–49 who are pregnant or likely to become pregnant and reside in selected geographic areas within selected PSUs. The PBS strategy includes women who are pregnant, ≥ age 18, reside in selected PSUs, and either seen at the first prenatal visit or seen initially in a hospital about to deliver.

  • c Number of newborns enrolled is larger than the number of mothers because of births of multiple gestation and the enrollment of siblings in a subsequent pregnancy.