Table 1 Characteristics included in definitions of onset of labor
From: Diagnosing onset of labor: a systematic review of definitions in the research literature
Characteristic included | N (%) |
|---|---|
Type of labor defined | Â |
 Latent | 3 (5) |
 First stage | 11 (18) |
 Active | 22 (35) |
 Labor (unspecified) | 15 (24) |
 More than one of the above | 11 (18) |
Cervical dilation | 42 (68) |
In latent phase labor | Â |
  < 2 cm | 1 (2) |
 3–4 cm | 3 (5) |
  > 4 cm | 7 (11) |
In active labor | Â |
  ≥ 2 cm | 2 (3) |
 3–4 cm | 10 (16) |
  > 4 cm | 14 (23) |
In first stage labor | Â |
 3–4 cm | 4 (6) |
  > 4 cm | 1 (2) |
In unspecified labor | Â |
  ≥ 2 cm | 2 (3) |
 3–4 cm | 2 (3) |
  > 4 cm | 2 (3) |
Cervical effacement | 12 (19) |
Regular painful contractions | 44 (71) |
Frequency of contractions | 12 (19) |
 1 in 8–10 min | 3 (5) |
 2 in 10 min or five minutes apart | 3 (5) |
 3 in 10 min | 5 (8) |
 1 every 3–5 mins | 2 (3) |
Other physiological symptoms | 7 (11) |
Rationale for definition | Â |
 Referred to women’s reports of onset or routine clinical practice | 11 (18) |
 Cited Friedman | 8 (13) |
 Cited Gross | 4 (6) |
 Cited textbooks | 3 (5) |
 Cited another study | 2 (3) |