Contraction frequency and acidemia at birth: A case–control study
Fuente:
Wiley Open Access
Gespeichert in:
| Hauptverfasser: | , , , , |
|---|---|
| Format: | Artículo Open Access |
| Veröffentlicht: |
Wiley
2026
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1867017708677103616 |
|---|---|
| author | Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst |
| author_facet | Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst |
| collection | Wiley Open Access |
| contents | Contraction frequency and acidemia at birth: A case–control study Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst Acta Obstetricia et Gynecologica Scandinavica Abstract Introduction Consensus is lacking regarding the upper limit for a safe contraction frequency during labor. We aimed to assess the association between different contraction frequencies and acidemia at birth, and whether an association was affected by oxytocin augmentation, concomitant cardiotocography (CTG) classification, and stage of labor. Material and Methods This is a case–control study based on CTG traces from births in southern Sweden during 2012–2017. Cases ( N = 364) had umbilical artery pH <7.1 if born by first‐stage cesarean section and pH <7.05 if born vaginally or by second‐stage cesarean. Controls were included with a 1:2 ratio ( N = 728) and had pH ≥7.15. CTG traces from the hour prior to birth were assessed blinded to the clinical outcome. Logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI). Results After excluding insufficient topography traces, 328 cases and 677 controls remained for analysis. Contraction frequencies 5, 5–6, and ≥6 per 10 min occurred in 15.2%, 19.5%, and 29.6% of cases and in 15.1%, 16.5%, and 11.1% of controls, respectively. The OR (95% CI) for acidemia were 1.6 (1.1–2.4), 1.9 (1.3–2.7), and 4.3 (3.0–6.2), respectively, compared with a reference group of <5. When comparing two separate binary cut‐offs of >5 and ≥5 contractions, similar strengths of association with acidemia were demonstrated with OR 2.7 (2.1–3.6) and 2.5 (1.9–3.3), respectively. The effect of contraction frequency >5 was similar in spontaneous ( n = 586) and oxytocin‐augmented ( n = 419) labor (OR 2.5, 1.7–3.8 vs. OR 2.4, 1.6–3.6), and whether the CTG was normal, suspicious, or pathological according to the Swedish CTG template (OR 2.1, 1.3–3.3; OR 3.5, 1.6–7.6; and OR 2.6, 1.4–4.7, respectively). The study lacked power to study any association during the first stage of labor. Conclusions Increasing contraction frequency is incrementally associated with fetal acidemia. Although an increased risk of acidosis is evident at contraction frequencies as low as five, such frequencies are common while acidemia is uncommon, implying a poor positive predictive value. A contraction frequency of more than five is associated with acidemia in both spontaneous and oxytocin‐augmented labor, and even when the fetal heart trace is normal. 10.1111/aogs.70181 http://creativecommons.org/licenses/by/4.0/ |
| doi_str_mv | 10.1111/aogs.70181 |
| format | Artículo Open Access |
| id | wiley_oa_10_1111_aogs_70181 |
| institution | Wiley Open Access |
| license_str_mv | http://creativecommons.org/licenses/by/4.0/ |
| publishDate | 2026 |
| publisher | Wiley |
| record_format | wiley_oa |
| spellingShingle | Contraction frequency and acidemia at birth: A case–control study Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst Acta Obstetricia et Gynecologica Scandinavica Contraction frequency and acidemia at birth: A case–control study Johanna Wagner Bjurström Gisela Rickle Maria Fogelberg Frida Ekengård Andreas Herbst Acta Obstetricia et Gynecologica Scandinavica Abstract Introduction Consensus is lacking regarding the upper limit for a safe contraction frequency during labor. We aimed to assess the association between different contraction frequencies and acidemia at birth, and whether an association was affected by oxytocin augmentation, concomitant cardiotocography (CTG) classification, and stage of labor. Material and Methods This is a case–control study based on CTG traces from births in southern Sweden during 2012–2017. Cases ( N = 364) had umbilical artery pH <7.1 if born by first‐stage cesarean section and pH <7.05 if born vaginally or by second‐stage cesarean. Controls were included with a 1:2 ratio ( N = 728) and had pH ≥7.15. CTG traces from the hour prior to birth were assessed blinded to the clinical outcome. Logistic regression was used to estimate odds ratios (OR) with 95% confidence intervals (CI). Results After excluding insufficient topography traces, 328 cases and 677 controls remained for analysis. Contraction frequencies 5, 5–6, and ≥6 per 10 min occurred in 15.2%, 19.5%, and 29.6% of cases and in 15.1%, 16.5%, and 11.1% of controls, respectively. The OR (95% CI) for acidemia were 1.6 (1.1–2.4), 1.9 (1.3–2.7), and 4.3 (3.0–6.2), respectively, compared with a reference group of <5. When comparing two separate binary cut‐offs of >5 and ≥5 contractions, similar strengths of association with acidemia were demonstrated with OR 2.7 (2.1–3.6) and 2.5 (1.9–3.3), respectively. The effect of contraction frequency >5 was similar in spontaneous ( n = 586) and oxytocin‐augmented ( n = 419) labor (OR 2.5, 1.7–3.8 vs. OR 2.4, 1.6–3.6), and whether the CTG was normal, suspicious, or pathological according to the Swedish CTG template (OR 2.1, 1.3–3.3; OR 3.5, 1.6–7.6; and OR 2.6, 1.4–4.7, respectively). The study lacked power to study any association during the first stage of labor. Conclusions Increasing contraction frequency is incrementally associated with fetal acidemia. Although an increased risk of acidosis is evident at contraction frequencies as low as five, such frequencies are common while acidemia is uncommon, implying a poor positive predictive value. A contraction frequency of more than five is associated with acidemia in both spontaneous and oxytocin‐augmented labor, and even when the fetal heart trace is normal. 10.1111/aogs.70181 http://creativecommons.org/licenses/by/4.0/ |
| title | Contraction frequency and acidemia at birth: A case–control study |
| topic | Acta Obstetricia et Gynecologica Scandinavica |
| url | https://obgyn.onlinelibrary.wiley.com/doi/10.1111/aogs.70181 |