TABLE 2.
Rate of indications associated with induced labor among inductions of singleton births in Iceland 1997–2018 (n = 14 985) by calendar time
| 1997–2001 | 2002–2007 | 2008–2013 | 2014–2018 | p‐value ** | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | |||
| 1 a | Pre‐eclampsia and eclampsia | 270 | 11.1 | 480 | 14.7 | 640 | 12.6 | 487 | 11.6 | <0.001 |
| 2 | Pregestational diabetes | 35 | 1.4 | 31 | 0.9 | 51 | 1.0 | 55 | 1.3 | 0.182 |
| 3 | Suspected placental insufficiency | 155 | 6.4 | 242 | 7.4 | 408 | 8.0 | 399 | 9.5 | <0.001 |
| 4 | Other hypertensive disorders | 170 | 7.0 | 232 | 7.1 | 578 | 11.4 | 465 | 11.1 | <0.001 |
| 5 | Gestational diabetes | 58 | 2.4 | 216 | 6.6 | 384 | 7.5 | 693 | 16.5 | <0.001 |
| 6 | Prolonged pregnancy | 396 | 16.2 | 737 | 22.6 | 558 | 11.0 | 993 | 23.7 | <0.001 |
| 7 | Obstetric cholestasis | 14 | 0.6 | 60 | 1.8 | 157 | 3.1 | 75 | 1.8 | <0.001 |
| 8 | Rh isoimmunization | 19 | 0.8 | 24 | 0.7 | 37 | 0.7 | 19 | 0.5 | 0.274 |
| 9 | Maternal wellbeing, other | 79 | 3.2 | 99 | 3.0 | 334 | 6.6 | 291 | 6.9 | <0.001 |
| 10 | Fetal wellbeing, other | 23 | 0.9 | 65 | 2.0 | 92 | 1.8 | 56 | 1.3 | 0.004 |
| 11 | Gestational age >41 weeks | 818 | 33.5 | 609 | 18.7 | 1085 | 21.3 | 233 | 5.6 | <0.001 |
| 12 | Maternal age ≥40 years | 13 | 0.5 | 19 | 0.6 | 39 | 0.8 | 49 | 1.2 | 0.158 |
| Missing | 398 | 16.3 | 451 | 13.8 | 727 | 14.3 | 385 | 9.2 | <0.001 | |
| Total labor inductions | 2439 | 100.0 | 3265 | 100.0 | 5090 | 100.0 | 4191 | 100.0 | ||
a
The designated order of importance is shown by numbers 1–12, with category number one being the most likely cause for induction and thus overriding all other indications.
**
p‐values were calculated with Chi‐Square test, testing for differences across time periods.