title: Emerging tocolytics: challenges in designing and testing drugs to delay preterm delivery and prolong pregnancy.
abstract: The global rate of preterm delivery (before 37 completed weeks of pregnancy) is increasing and there are no effective means available to prevent this rise. Prematurity is the principal cause of neonatal mortality and a major cause of pediatric morbidity and long-term disability. Current strategies to prolong pregnancy are based on inhibiting the mechanisms that effect uterine smooth muscle (myometrium) contractions in women who are in preterm labor. Most drugs in this group were developed for other purposes. Newer strategies are designed to maintain a state of uterine quiescence and pregnancy, preventing the myometrium from initiating contractions and entering preterm labor. Again, it may be possible to use existing drugs for pregnancy maintenance. Several financial and practical barriers exist for developing completely new drugs to delay labor. Designing clinical trials to test tocolytics is complicated, as the health of two patients must be considered and the nature of preterm birth and its outcomes are different at early preterm labor (< 28 weeks) and late preterm labor (34 - 36 weeks).
authors.affiliation: University of Alberta, AHFMR Interdisciplinary Team in Preterm Birth and Healthy Outcomes, Department of Obstetrics and Gynecology, 220 HMRC, Edmonton, T6G 2S2, Alberta, Canada. david.olson@ualberta.ca
authors.forename: David M
authors.initials: DM
authors.lastname: Olson
authors.forename: Inge
authors.initials: I
authors.lastname: Christiaens
authors.forename: Sara
authors.initials: S
authors.lastname: Gracie
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Bryan F
authors.initials: BF
authors.lastname: Mitchell
mesh_terms: D015195:Drug Design; D015507:Drugs, Investigational / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007745:Labor Onset / Q000187:drug effects*; D007752:Obstetric Labor, Premature / Q000503:physiopathology / Q000517:prevention & control*; D011247:Pregnancy; D015145:Tocolysis / Q000009:adverse effects / Q000379:methods*; D015149:Tocolytic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D015507:Drugs, Investigational; D015149:Tocolytic Agents