Probiotics for preventing gestational diabetes
Sarah J Davidson, Helen L Barrett, Sarah A Price, Leonie K Callaway, Marloes Dekker Nitert, Sarah J Davidson, Helen L Barrett, Sarah A Price, Leonie K Callaway, Marloes Dekker Nitert
Abstract
Background: Gestational diabetes mellitus (GDM) is associated with a range of adverse pregnancy outcomes for mother and infant. The prevention of GDM using lifestyle interventions has proven difficult. The gut microbiome (the composite of bacteria present in the intestines) influences host inflammatory pathways, glucose and lipid metabolism and, in other settings, alteration of the gut microbiome has been shown to impact on these host responses. Probiotics are one way of altering the gut microbiome but little is known about their use in influencing the metabolic environment of pregnancy. This is an update of a review last published in 2014.
Objectives: To systematically assess the effects of probiotic supplements used either alone or in combination with pharmacological and non-pharmacological interventions on the prevention of GDM.
Search methods: We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (20 March 2020), and reference lists of retrieved studies.
Selection criteria: Randomised and cluster-randomised trials comparing the use of probiotic supplementation with either placebo or diet for the prevention of the development of GDM. Cluster-randomised trials were eligible for inclusion but none were identified. Quasi-randomised and cross-over design studies were not eligible for inclusion in this review. Studies presented only as abstracts with no subsequent full report of study results were only included if study authors confirmed that data in the abstract came from the final analysis. Otherwise, the abstract was left awaiting classification.
Data collection and analysis: Two review authors independently assessed study eligibility, extracted data and assessed risk of bias of included studies. Data were checked for accuracy.
Main results: In this update, we included seven trials with 1647 participants. Two studies were in overweight and obese women, two in obese women and three did not exclude women based on their weight. All included studies compared probiotics with placebo. The included studies were at low risk of bias overall except for one study that had an unclear risk of bias. We excluded two studies, eight studies were ongoing and three studies are awaiting classification. Six included studies with 1440 participants evaluated the risk of GDM. It is uncertain if probiotics have any effect on the risk of GDM compared to placebo (mean risk ratio (RR) 0.80, 95% confidence interval (CI) 0.54 to 1.20; 6 studies, 1440 women; low-certainty evidence). The evidence was low certainty due to substantial heterogeneity and wide CIs that included both appreciable benefit and appreciable harm. Probiotics increase the risk of pre-eclampsia compared to placebo (RR 1.85, 95% CI 1.04 to 3.29; 4 studies, 955 women; high-certainty evidence) and may increase the risk of hypertensive disorders of pregnancy (RR 1.39, 95% CI 0.96 to 2.01, 4 studies, 955 women), although the CIs for hypertensive disorders of pregnancy also indicated probiotics may have no effect. There were few differences between groups for other primary outcomes. Probiotics make little to no difference in the risk of caesarean section (RR 1.00, 95% CI 0.86 to 1.17; 6 studies, 1520 women; high-certainty evidence), and probably make little to no difference in maternal weight gain during pregnancy (MD 0.30 kg, 95% CI -0.67 to 1.26; 4 studies, 853 women; moderate-certainty evidence). Probiotics probably make little to no difference in the incidence of large-for-gestational age infants (RR 0.99, 95% CI 0.72 to 1.36; 4 studies, 919 infants; moderate-certainty evidence) and may make little to no difference in neonatal adiposity (2 studies, 320 infants; data not pooled; low-certainty evidence). One study reported adiposity as fat mass (MD -0.04 kg, 95% CI -0.12 to 0.04), and one study reported adiposity as percentage fat (MD -0.10%, 95% CI -1.19 to 0.99). We do not know the effect of probiotics on perinatal mortality (RR 0.33, 95% CI 0.01 to 8.02; 3 studies, 709 infants; low-certainty evidence), a composite measure of neonatal morbidity (RR 0.69, 95% CI 0.36 to 1.35; 2 studies, 623 infants; low-certainty evidence), or neonatal hypoglycaemia (mean RR 1.15, 95% CI 0.69 to 1.92; 2 studies, 586 infants; low-certainty evidence). No included studies reported on perineal trauma, postnatal depression, maternal and infant development of diabetes or neurosensory disability.
Authors' conclusions: Low-certainty evidence from six trials has not clearly identified the effect of probiotics on the risk of GDM. However, high-certainty evidence suggests there is an increased risk of pre-eclampsia with probiotic administration. There were no other clear differences between probiotics and placebo among the other primary outcomes. The certainty of evidence for this review's primary outcomes ranged from low to high, with downgrading due to concerns about substantial heterogeneity between studies, wide CIs and low event rates. Given the risk of harm and little observed benefit, we urge caution in using probiotics during pregnancy. The apparent effect of probiotics on pre-eclampsia warrants particular consideration. Eight studies are currently ongoing, and we suggest that these studies take particular care in follow-up and examination of the effect on pre-eclampsia and hypertensive disorders of pregnancy. In addition, the underlying potential physiology of the relationship between probiotics and pre-eclampsia risk should be considered.
Trial registration: ClinicalTrials.gov NCT00167700 NCT01922791 NCT02692820 NCT01436448 NCT04009889.
Conflict of interest statement
SJD: none.
HB: recieved a grant from the NHMRC, Australia (a competitive government research grant) to undertake a randomised control trial of probiotics for the prevention of gestational diabetes mellitus and I was an associate investigator this trial (Callaway 2019). In this review, HB was not involved in any decisions relating to this trial: assessment of the trial for inclusion, assessment of risk of bias and data extraction were carried out by individuals who were not directly involved in the trial. SJD and SAP carried out these tasks. Chr. Hansen A/S have donated the probiotics and matching placebo to the SPRING study (Callaway 2019) that was conducted by authors Barrett, Dekker Nitert and Callaway. While the authors are grateful for this donation from Chr.Hansen A/S, the conduct of the study, analysis and publication of the results is entirely independent of Chr. Hansen A/S.
SAP: none.
LC: was chief investigator in a trial examining the use of probiotics for preventing gestational diabetes mellitus (Callaway 2019), which was funded from a grant from the NHMRC, Australia (a competitive government research grant). In this review, LC was not involved in any decisions relating to this trial: assessment of the trial for inclusion, assessment of risk of bias and data extraction were carried out by individuals who were not directly involved in the trial. SJD and SAP carried out these tasks. Chr. Hansen A/S have donated the probiotics and matching placebo to the SPRING study (Callaway 2019) that was conducted by authors Barrett, Dekker Nitert and Callaway. While the authors are grateful for this donation from Chr.Hansen A/S, the conduct of the study, analysis and publication of the results is entirely independent of Chr. Hansen A/S.
MDN: was scientific lead in a trial examining the use of probiotics for preventing gestational diabetes mellitus (Callaway 2019), which was funded from a grant from the NHMRC, Australia (a competitive government research grant). In this review, MDN was not involved in any decisions relating to this trial: assessment of the trial for inclusion, assessment of risk of bias and data extraction were carried out by individuals who were not directly involved in the trial. SJD and SAP carried out these tasks. Chr. Hansen A/S have donated the probiotics and matching placebo to the SPRING study (Callaway 2019) that was conducted by authors Barrett, Dekker Nitert and Callaway. While the authors are grateful for this donation from Chr.Hansen A/S, the conduct of the study, analysis and publication of the results is entirely independent of Chr. Hansen A/S.
Copyright © 2021 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Figures
Source: PubMed