Design and Overview of PIN3 and PIN3plus

The third phase of the PIN Study was a prospective cohort data collection effort examining whether physical activity or stress (PIN3), or placental vascular compromise (PIN3plus) are associated with preterm birth. Because protocols are common for PIN3 and PIN3plus for most women, they are described together and referred to as PIN3.

PIN3 includes a cohort of pregnant women seeking services from prenatal clinics at UNC Hospitals. Recruitment began in January 2001 and ended in June 2005, with 2006 women recruited. Placenta collection began July 2002.

Women were recruited for enrollment at <20 weeks gestation, and were asked to complete the following:

2 research clinic visits — one at <20 weeks gestation and one at 24–29 weeks gestation
2 telephone interviews — one at 17–22 weeks gestation and one at 27–30 weeks gestation
2 self-administered questionnaires — distributed at each of the clinic visits
a food frequency questionnaire — distributed at the second clinic visit

After delivery, placentas were collected, and women were asked to complete a brief questionnaire while in the hospital.

Following delivery, medical charts were abstracted.