The grades of evidence (I-III) and levels of recommendations (A-C) are defined at the end of the "Major Recommendations" field.
The following recommendations are based on good and consistent scientific evidence (Level A):
- Women with postterm gestations who have unfavorable cervices can either undergo labor induction or be managed expectantly.
- Prostaglandin can be used in postterm pregnancies to promote cervical ripening and induce labor.
- Delivery should be effected if there is evidence of fetal compromise or oligohydramnios.
The following recommendations are based primarily on consensus and expert opinion (Level C):
- Despite a lack of evidence that monitoring improves perinatal outcome, it is reasonable to initiate antenatal surveillance of postterm pregnancies between 41 weeks (287 days; estimated delivery date [EDD] +7 days) and 42 weeks (294 days; EDD +14 days) of gestation because of evidence that perinatal morbidity and mortality increase as gestational age advances.
- Many practitioners use twice-weekly testing with some evaluation of amniotic fluid volume beginning at 41 weeks of gestation. A nonstress test and amniotic fluid volume assessment (a modified biophysical profile [BPP]) should be adequate.
- Many authorities recommend prompt delivery in a postterm patient with a favorable cervix and no other complications.
Definitions:
Grades of Evidence:
I: Evidence obtained from at least 1 properly designed randomized controlled trial.
II-1: Evidence obtained from well-designed controlled trials without randomization.
II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than 1 center or research group.
II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments could also be regarded as this type of evidence.
III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.
Levels of Recommendation
Level A — Recommendations are based on good and consistent scientific evidence.
Level B — Recommendations are based on limited or inconsistent scientific evidence.
Level C — Recommendations are based primarily on consensus and expert opinion.