Table 1  Baseline values and observed changes related to fluids given until birth. Group differences analysed using Kruskal–Wallis nonparametric ANOVA and Mann–Whitney U test
Control group elective caesarean (n = 26)  Total fluids given until birth  Kruskal–Wallis P value  Mann–Whitney P value
Fluid group 1 <1000 ml (n = 113)  Fluid group 2 1000–2500 ml (n = 87)  Fluid group 3 >2500 ml (n = 61)
Median  Q1–Q3  Median  Q1–Q3  Median  Q1–Q3  Median  Q1–Q3
Mother
Age  32  27–35  31  28–34  30  27–33  30  26–33  0.117
Weight before pregnancy (kg)  67  58–78  66  59–73  67  60–77  66  60–77  0.750
Body mass index before pregnancy  26.2  22.6–28.1  23.7  21.0–25.5  24.1  21.5–27.9  23.9  22.1–27.1  0.066
Weight at term (kg)  83  72–89  79  71–89  80  74–90  83  74–91  0.399
Weight increase  12  10–18  13  11–16  14  10–17  15  11–19  0.466
Gestational weeks  38.5  38.3–38.7  39.7  39.0–40.6  40.0  39.1–40.9  40.3  39.6–41.0  0.087
Cervical dilatation at admission (cm)  —  —  5.0  4.0–7.0  4.0  3.0–4.0  3.0  2.0–4.0  <0.001  <0.001
Duration of labour (hours)  —  —  1.6  0.9–3.0  5.9  4.3–8.9  12.2  9.8–14.7  <0.001  <0.001
Duration second stage (hours)  —  —  0.2  0.1–0.5  0.5  0.2–1.0  0.6  0.4–1.0  <0.001  <0.001
Oral fluids (ml/hour)  0  0–0  185  79–316  196  136–305  196  154–263  0.429
Intravenous fluid (ml/hour)  Not measured  Not measured  0  0–0  52  3–102  94  53–144  <0.001  <0.001
Total fluid (ml/hour)  Not measured  Not measured  194  100–325  291  201–362  314  260–360  <0.001  <0.001
Total fluid (ml)  Not measured  Not measured  400  200–575  1680  1355–2050  3570  2925–4355  —
Oxytocin (ml)  —  —  0  0–0  50  0–166  200  100–400  <0.001  <0.001
Oxytocin (units)  —  —  0.0  0.0–0.0  1.0  0.0–3.3  4.0  2.0–8.0  <0.001  <0.001
Oxytocin (maximum rate mU/minute)*  —  —  10  5–20  20  10–30  40  20–60  <0.001  <0.001
Duration epidural (hours)  —  —  1.7  1.7–1.7  4.3  2.9–6.1  8.8  6.8–10.6  —
Osmolality at baseline (mOsm/kg)  279  277–281  280  277–282  280  276–282  279  277–281  0.501
Osmolality postpartum (mOsm/kg)  280  277–282  282  279–284  277  276–281  274  272–277  <0.001  <0.001**
Na at baseline (mmol/l)  137  136–138  137  136–137  136  135–137  136  135–138  0.238
Na postpartum (mmol/l)  137  137–138  136  135–137  135  133–136  133  130–135  <0.001  <0.001**
Na change (mmol/l)  0.0  −1.0 to 1.0  0.0  −1.0 to 1.0  −2.0  −3.0 to −1.0  −3.0  −5.0 to −1.0  <0.001  <0.001**
Glucose at baseline (mmol/l)  5.0  4.5–5.5  5.1  4.7–5.8  5.2  4.9–5.9  5.3  4.8–6.2  0.133
Glucose postpartum (mmol/l)  4.8  4.2–5.1  6.7  5.9–7.9  7.7  6.5–9.4  7.8  6.9–9.4  <0.001  <0.001**
Umbilical cord
Arterial BE  −2.0  −3.0 to −1.0  −4.0  −6.0 to −3.0  −5.0  −7.0 to −3.0  −6.0  −9.0 to −3.0  <0.001  0.006**
Arterial pH  7.27  7.24–7.29  7.26  7.22–7.31  7.24  7.19–7.29  7.24  7.17–7.29  0.042  0.014***
Arterial Na (mmol/l)  139  138–140  139  137–140  137  136–139  136  134–138  <0.001  <0.001**
Arterial–venous Na difference (mmol/l)  1.0  0.0–1.0  1.0  0.0–2.0  1.0  0.0–2.0  1.0  0.0–2.0  0.736
Arterial glucose (mmol/l)  3.4  3.0–3.7  4.2  3.6–5.0  5.2  4.2–6.1  5.4  4.7–6.6  <0.001  <0.001**
Infant
Birthweight (g)  3415  3120–3790  3535  3305–3850  3670  3360–4160  3805  3580–4040  0.001  0.001**
All group differences are compared with Kruskal–Wallis nonparametric analysis of variance (ANOVA). When significant differences are found, Mann–Whitney U test is performed to analyse differences between fluid groups 1 and 3.
*  Including only subjects who received oxytocin. Maximum rate mU/minute: maximum rate of oxytocin infusion during first stage of labour.
**  Differences between control group elective caesarean and fluid group 3: P < 0.001 (Mann–Whitney) (additional significant test).
***  Difference between control group elective caesarean and fluid group 3: P = 0.14 (Mann–Whitney) (additional significant test).