Lactate production as a response to intrapartum hypoxia in the growth-restricted fetus.
OBJECTIVE
To analyse whether the increase in lactate in response to intrapartum hypoxia differs between small- (SGA), appropriate- (AGA) and large-for-gestational-age (LGA) fetuses.


METHODS
Observational cohort study.


METHODS
Ten obstetric units in Sweden.


METHODS
A cohort of 1496 women.


METHODS
A secondary analysis of a randomised controlled trial, in which 1496 women with fetal heart rate abnormalities, indicating fetal scalp blood sampling, were randomised to lactate analyses. After delivery, the neonates were divided according to birthweight for gestational age into SGA, AGA and LGA groups.


METHODS
Lactate concentration in fetal scalp blood.


METHODS
Acid-base balance in cord artery blood and Apgar score <7 at 5 minutes.


RESULTS
Median lactate concentrations in the SGA, AGA and LGA groups were 3.8, 3.0 and 2.2 mmol/l, respectively (SGA versus AGA, P = 0.017; LGA versus AGA, P = 0.009). In the subgroups with scalp lactate >4.8 mmol/l (lactacidaemia), the corresponding median (range) values were 6.2 (4.9-14.6), 5.9 (4.9-15.9) and 5.7 mmol/l (5.0-7.9 mmol/l), respectively (no significant differences between the groups). The proportions of neonates with cord artery pH < 7.00, metabolic acidaemia or Apgar score <7 at 5 minutes were similar in all weight groups.


CONCLUSIONS
SGA fetuses with fetal heart rate abnormalities have the same ability to produce lactate as a response to intrapartum hypoxia as AGA and LGA fetuses. The risk of a poor outcome associated with high lactate concentration is the same in SGA, AGA and LGA fetuses. Scalp blood lactate analysis is therefore a reliable method for intrapartum fetal surveillance of suspected growth-restricted fetuses scheduled for vaginal delivery at ≥ 34 weeks of gestation.
Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. malin.holzmann@ki.se
M
M
Holzmann
S
S
Cnattingius
L
L
Nordström
D000140:Acidosis, Lactic / Q000378:metabolism; D000328:Adult; D001724:Birth Weight; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005317:Fetal Growth Retardation / Q000378:metabolism*; D005311:Fetal Hypoxia / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D019344:Lactic Acid / Q000096:biosynthesis* / Q000097:blood; D011247:Pregnancy; D011446:Prospective Studies; D012535:Scalp / Q000737:chemistry; D013548:Sweden; D055815:Young Adult
D019344:Lactic Acid