II. Definitions
- Late Deceleration
- Late Decelerations start after the contraction
- Onset to Late Deceleration nadir >=30 seconds
- Ends after contraction is over
- Contrast with Early Deceleration which mirrors the contraction
- Subtle Late Decelerations may also be significant
- Recurrent Late Decelerations
- Late Decelerations that occur with >50% of contractions in 20 minutes
- Prolonged Late Decelerations
- Late Decelerations that last >2 minutes
III. Causes
- More ominous if associated with decreased variability
- Uteroplacental insufficiency
- Fetal acidosis
- Fetal Hypoxemia
IV. References
- Bailey (2000) ALSO, E:1-13
- Gabbe (2002) Obstetrics, p. 395
- Arnold (2020) Am Fam Physician 102(3): 158-67 [PubMed]
- Rylander (2001) Clin Fam Pract 3(2):287-305 [PubMed]