Is there a difference in: 1) the length of gestational age of infants of high-risk pregnant women who receive the medical intervention and high-risk pregnant women who receive the SOC? 2) in health care costs between women who receive the medical intervention and the SOC? 3) intervals between the current pregnancy and a subsequent pregnancy across groups? and 4) in length of gestational age of current infant with gestational age of index prior preterm birth?