POST-TERM PREGNANCY

• Definition = gestation at or beyond 42wks
• Risk factors
  • Primiparity
  • Previous post-term pregnancy
  • Male fetus
• Post-term pregnancy is associated with increased risks of:
  • Perinatal mortality for fetus
  • Labor dystocia
  • Perineal injury (with vaginal birth)
  • Cesarean delivery
• Management of post-term pregnancy
  • Antepartum fetal festing
    • Not shown to decrease perinatal mortality as of 2004 but nonetheless commonly performed 2x/wk starting at 41wks
    • Modalities include non-stress testing, biophysical profile, contraction stress testing
  • Induction of Labor
    • Strongly recommended by ACOG as of 2004 if there is evidence of fetal compromise of oligohydramnios
    • Per ACOG, "many authorities" recommend induction no later than 42wks if cervix is favorable
    • Per ACOG 2004, expectant management is appropriate if cervix if unfavorable
    • In a meta-analysis of 11 randomized controlled trials of induction of labor vs. expectant monitoring, in pregnancies at 41+ wks, expectant management was associated with a sig. increase in risk of cesariean delivery (RR 1.21) and meconium staining of amniotic fluid (RR 1.70) (Ann. Int. Med. 151:252, 2009-JW)

(Sources include: ACOG guidelines published in Obs. Gyn Sep. 2004, cited in AFP 70:2221, 2004)