Use of biochemical tests of placental function for improving pregnancy outcome.Cochrane Database Syst Rev. 2015 Nov 25; 2015(11):CD011202.CD
The placenta has an essential role in determining the outcome of pregnancy. Consequently, biochemical measurement of placentally-derived factors has been suggested as a means to improve fetal and maternal outcome of pregnancy.
To assess whether clinicians' knowledge of the results of biochemical tests of placental function is associated with improvement in fetal or maternal outcome of pregnancy.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2015) and reference lists of retrieved studies.
Randomised, cluster-randomised or quasi-randomised controlled trials assessing the merits of the use of biochemical tests of placental function to improve pregnancy outcome.Studies were eligible if they compared women who had placental function tests and the results were available to their clinicians with women who either did not have the tests, or the tests were done but the results were not available to the clinicians. The placental function tests were any biochemical test of placental function carried out using the woman's maternal biofluid, either alone or in combination with other placental function test/s.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed trials for inclusion, extracted data and assessed trial quality. Authors of published trials were contacted for further information.
Three trials were included, two quasi-randomised controlled trials and one randomised controlled trial. One trial was deemed to be at low risk of bias while the other two were at high risk of bias. Different biochemical analytes were measured - oestrogen was measured in one trial and the other two measured human placental lactogen (hPL). One trial did not contribute outcome data, therefore, the results of this review are based on two trials with 740 participants.There was no evidence of a difference in the incidence of death of a baby (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.36 to 2.13, two trials, 740 participants (very low quality evidence)) or the frequency of a small-for-gestational-age infant (RR 0.44, 95% CI 0.16 to 1.19, one trial, 118 participants (low quality evidence)).In terms of this review's secondary outcomes, there was no evidence of a clear difference between women who had biochemical tests of placental function compared with standard antenatal care for the incidence of stillbirth (RR 0.56, 95% CI 0.16 to 1.88, two trials, 740 participants (very low quality evidence)) or neonatal death (RR 1.62, 95% CI 0.39 to 6.74, two trials, 740 participants, very low quality evidence)) although the directions of any potential effect were in opposing directions. There was no evidence of a difference between groups in elective delivery (RR 0.98, 95% CI 0.84 to 1.14, two trials, 740 participants (low quality evidence)), caesarean section (one trial, RR 0.48, 95% CI 0.15 to 1.52, one trial, 118 participants (low quality evidence)), change in anxiety score (mean difference -2.40, 95% CI -4.78 to -0.02, one trial, 118 participants), admissions to neonatal intensive care (RR 0.32, 95% CI 0.03 to 3.01, one trial, 118 participants), and preterm birth before 37 weeks' gestation (RR 2.90, 95% CI 0.12 to 69.81, one trial, 118 participants). One trial (118 participants) reported that there were no cases of serious neonatal morbidity. Maternal death was not reported.A number of this review's secondary outcomes relating to the baby were not reported in the included studies, namely: umbilical artery pH < 7.0, neonatal intensive care for more than seven days, very preterm birth (< 32 weeks' gestation), need for ventilation, organ failure, fetal abnormality, neurodevelopment in childhood (cerebral palsy, neurodevelopmental delay). Similarly, a number of this review's maternal secondary outcomes were not reported in the included studies (admission to intensive care, high dependency unit admission, hospital admission for > seven days, pre-eclampsia, eclampsia, and women's perception of care).