A Cochrane review [Abstract] 1 included 2 studies with a total of 3348 subjects. Mother-baby pairs were allocated to either lactate or pH estimation of foetal blood samples in labour. There were no statistically significant differences for any foetal/neonatal/infant outcomes, including low Apgar score at five minutes, admission to neonatal intensive care units or neonatal encephalopathy, or for low umbilical arterial pH, base deficit or metabolic acidaemia. There was a statistically higher success rate for lactate compared with pH estimation (RR 1.10, 95% CI 1.08 to 1.12; n=2992). There were no significant between-group differences in mode of birth or operative birth for non-reassuring foetal status. No studies reported outcomes of maternal satisfaction, anxiety, length of hospital stay or economic analysis.
A cohort study 2 assessed the value of lactate in fetal scalp blood at delivery and the outcomes of the offspring at four years of age. With normal scalp lactate concentration, the number of children with a diagnosed disorder was lower compared to the pre-acidemic/acidemic groups, although the findings were only significant for fine motor dysfunction (p = 0.036). Elevated lactate values were significantly associated with increased risk for a poorer capacity of attention and understanding of instructions (OR 1.37, 95% CI 1.07 to 1.74; n=307), and for fine motor dysfunction (OR 1.22, 95% CI 1.00 to 1.49; n=307) at the age of four.
Comment: The quality of evidence is downgraded by study quality (unclear sequence generation in one study, no blinding ). </para>
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