Background: Maternal psychosocial stress during pregnancy is associated with adverse neonatal outcomes. These outcomes result from changes in fetal brain development and lead to disrupted cognitive, behavioural and emotional development. The neurosteroid allopregnanolone has been shown to reduce neural excitability and aid in protecting the fetal brain from excitotoxic insults. The objectives of this study were to assess the effect of prenatal maternal stress on fetal brain development with and without maternal allopregnanolone treatment. Methods: Pregnant guinea pigs were subjected to stress induced by exposure to a strobe light at 50, 55, 60 and 65 days gestation. Salivary cortisol levels were measured before and after each exposure. Fetal brains were assessed for markers of brain development using immunohistochemistry and plasma allopregnanolone was measured by radioimmunoassay. Results: Female, but not male prenatal stress-exposed fetuses demonstrated higher brain-to-liver ratios (BLR). Male fetuses showed significantly reduced expression of myelin basic protein (MBP), glial fibrillary acidic protein (GFAP), and both males and females showed reduced expression of microtubule-associated protein 2 (MAP2). These markers were not affected by maternal allopregnanolone treatment. However, maternal allopregnanolone treatment resulted in an increase in fetal plasma allopregnanolone concentrations in control pregnancies but concentrations were not raised after prenatal stress exposure. Conclusions: These findings indicate that the effects of prenatal stress on fetal brain development are sexually dimorphic with more pronounced negative effects seen on male neurodevelopment. Allopregnanolone treatment was not effective in raising fetal plasma concentrations after prenatal stress suggesting a stress-induced dysregulation of neurosteroid pathways during gestation. Interestingly, this study directly implicates prenatal stress in the disruption of fetal neurosteroid levels, such that it may mediate some of the deleterious effects on fetal neurodevelopment by facilitating a deficit in normal endogenous neuroprotective mechanisms.

Prenatal stress has been associated with detrimental outcomes of pregnancy, including altered brain development leading to behavioural pathologies. The neurosteroid allopregnanolone has been implicated in mediating some of these adverse outcomes following prenatal stress due to its potent inhibitory and anxiolytic effects on the brain. The aims of the current study were to characterise key markers for brain development as well as behavioural parameters, adrenocortical responses to handling and possible neurosteroid influences towards outcomes in guinea pig offspring in childhood. Pregnant guinea pig dams were exposed to strobe light for 2 h (9-11 a.m.) on gestational days 50, 55, 60, and 65 and were left to deliver spontaneously at term and care for their litter. Behavioural testing (open-field test, object exploration test) of the offspring was performed at postnatal day 18 (with salivary cortisol and DHEA measured), and brains were collected at post-mortem on day 21. Markers of brain development myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) were assessed via immunohistochemistry, and the neurosteroid allopregnanolone and its rate-limiting enzymes 5α-reductase types 1 and 2 (5αR1/2) were measured in neonatal brains by radioimmunoassay, reverse transcriptase polymerase chain reaction (RT-PCR), and Western blot, respectively. Brain-derived neurotrophic factor protein was measured as a marker of synaptic plasticity, and GABA_A receptor subunit expression was also assessed using RT-PCR. Neonates born from mothers stressed during late pregnancy showed a reduction in both MBP (p < 0.01) and GFAP (p < 0.05) expression in the CA1 region of the hippocampus at 21 days of age. Pups of prenatally stressed pregnancies also showed higher levels of anxiety and neophobic behaviours at the equivalent of childhood (p < 0.05). There were no significant changes observed in allopregnanolone levels, 5αR1/2 expression, or GABA_A receptor subunit expression in prenatally stressed neonates compared to controls. This study shows alterations in markers of myelination and reactive astrocytes in the hippocampus of offspring exposed to prenatal stress. These changes are also observed in offspring that show increased anxiety behaviours at the equivalent of childhood, which indicates ongoing structural and functional postnatal changes after prenatal stress exposure.

BackgroundRecruitment of pregnant women into trials is a challenge exacerbated by a number of factors, including strict eligibility criteria. There has been little in-depth examination of the recruitment process to trials involving pregnant women. This paper presents the findings of a study conducted to identify facilitators and challenges in recruiting pregnant women to the Communicating Healthy Beginnings Advice by Telephone (CHAT) randomised controlled trial, which aims to reduce the prevalence of infant and childhood obesity.MethodsData were collected from (1) administration of a short questionnaire to women at the time of recruitment exploring women’s reasons for consent and non-consent; (2) interviews with recruiters to capture recruiters’ experiences of the recruitment process; and (3) analysis of field notes taken by recruiters on the number of women approached/recruited and reasons as to why they did not consent to participate. Data obtained were triangulated to gain insights into the process of recruiting pregnant women.ResultsA total of 1155 pregnant women (mean gestational age 31.5 weeks) were enrolled over 5 months. The main reasons for women consenting to participate in the study were convenience in programme delivery mode via telephone calls or text messages, altruism and because the programme was free of charge. The main reasons for women not consenting were lack of interest, language challenges/difficulty speaking English and some felt they did not need information and support due to prior experience as a mother. Facilitators included organisational support, rapport with recruiters and some women with no other children who needed advice. Despite the challenges, the mode of delivery of intervention via telephone calls or text messages, the minimal effort required of women to participate, organisational support from the lead site and recruiters’ knowledge of and commitment towards the trial contributed towards successful recruitment.ConclusionDespite some challenges in recruiting pregnant women to an infant obesity prevention programme, some of the facilitators in recruitment included mode of delivery of the intervention programme via telephone calls or text messages, the minimal effort required for women to participate, organisational support from the lead site, and recruiters’ knowledge of and commitment towards the trial.Trial registrationThe CHAT RCT is registered with the Australian Clinical Trial Registry (ACTRN12616001470482p); Ethics Review Committee of Sydney Local Health District (Protocol No. X16–0360 & LNR/16/RPAH/495).

A sensitive and specific double-antibody enzyme-linked immunoassay, using a synthetic analogue of human relaxin for standard and immunogen, was developed for the measurement of human relaxin (hRLX) in serum and plasma. No cross-reactivity was observed for human insulin, human insulin-like growth factor-I, hGH, human chorionic gonadotropin, hFSH, hLH or human prolactin. The assay was used to monitor RLX concentrations in samples from men, non-pregnant and pregnant women, and in pregnant rhesus monkeys infused with hRLX. RLX was not detected in serum from men nor from non-pregnant women, while a concentration of 600 ng/l was measured in pooled sera from two pregnant women (pregnancies achieved by in-vitro fertilization). Immunoreactive RLX (1.1 micrograms/g) was found in human corpora lutea taken from ectopic pregnancies at 7 weeks. In an experiment with a pregnant rhesus monkey infused with human RLX analogue, less than 1.5% of the maternal concentration was measured in the fetal circulation. Even though preliminary, these data suggest a low level of transfer of human analogue relaxin across the placenta in a rhesus monkey. Further studies of the physiology of RLX in human pregnancy will be facilitated by the availability of this immunoassay.

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