Maternal bacteria to correct abnormal gut microbiota in babies born by C-section

INTRODUCTION

There is evidence that caesarean section (CS) is associated with increased risk of childhood obesity, asthma, and coeliac disease. The gut microbiota of CS-born babies differs to those born vaginally, possibly due to reduced exposure to maternal vaginal bacteria during birth. Vaginal seeding is a currently unproven practice intended to reduce such differences, so that the gut microbiota of CS-born babies is similar to that of babies born vaginally. Our pilot study, which uses oral administration as a novel form of vaginal seeding, will assess the degree of maternal strain transfer and overall efficacy of the procedure for establishing normal gut microbiota development.

METHODS AND ANALYSIS

Protocol for a single-blinded, randomized, placebo-controlled pilot study of a previously untested method of vaginal seeding (oral administration) in 30 CS-born babies. A sample of maternal vaginal bacteria is obtained prior to CS, and mixed with 5 ml sterile water to obtain a supernatant. Healthy babies are randomized at 1:1 to receive active treatment (3 ml supernatant) or placebo (3 ml sterile water). A reference group of 15 non-randomized vaginal-born babies are also being recruited. Babies' stool samples will undergo whole metagenomic shotgun sequencing to identify potential differences in community structure between CS babies receiving active treatment compared to those receiving placebo at age 1 month (primary outcome). Secondary outcomes include differences in overall gut community between CS groups (24 hours, 3 months); similarity of CS-seeded and placebo gut profiles to vaginally-born babies (24 hours, 1 and 3 months); degree of maternal vaginal strain transfer in CS-born babies (24 hours, 1 and 3 months); anthropometry (1 and 3 months) and body composition (3 months).

ETHICS AND DISSEMINATION

Ethics approval by the Northern A Health and Disability Ethics Committee (18/NTA/49). Results will be published in peer-reviewed journals and presented at international conferences.

REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12618000339257).

Hyperemesis gravidarum and long-term health of the offspring

Nausea and vomiting of pregnancy is a very common occurrence, but the reported incidence of hyperemesis gravidarum (a more severe form of vomiting in pregnancy) is much lower, estimated to vary from 0.3-3.6%. Studies have shown that nausea and vomiting of pregnancy is associated with improved fetal outcomes, such as lower rates of miscarriage. However, there are limited data on outcomes associated with hyperemesis gravidarum, which have focused on pregnancy and neonatal outcomes. Recently, studies showed adverse health outcomes, such as a reduction in insulin sensitivity in childhood and increased incidence of psychological disorders in adulthood. The effects of hyperemesis gravidarum in the offspring need to be further examined throughout childhood, adolescence, and into adulthood, so that long-term disease risks can be evaluated.

Insulin sensitivity and β-cell function in adults born preterm and their children

We aimed to evaluate insulin secretion and insulin sensitivity in adults born preterm and their children. Subjects were adults born both preterm and at term, with their children aged 5-10 years born at term. Insulin sensitivity and secretion were assessed using hyperglycemic clamps in adults and frequently sampled intravenous glucose tolerance tests using Bergman minimal model in children. In total, 52 adults aged 34-38 years participated (31 born preterm, mean gestational age 33.3 weeks). Adults born preterm were less insulin sensitive than those born at term (19.0 ± 2.5 vs. 36.3 ± 5.2 mg · kg(-1) · min(-1)mU · L; P < 0.05) with compensatory increased first-phase insulin secretion (56.1 ± 8.5 vs. 25.3 ± 3.7 mU/L; P < 0.001) but similar disposition index indicating appropriate insulin secretion. These differences were independent of sex and remained when subjects born <32 weeks' gestation were excluded from analyses. In total, 61 children were studied (37 of preterm parents, mean age 7.9 ± 0.3 years). Children of parents born preterm had similar insulin sensitivity to children of parents born at term, but a correlation between parental and offspring insulin sensitivity was noted only among children of parents born preterm. In conclusion, adults born preterm have insulin resistance in midadulthood, but this was not associated with insulin resistance in their children.