Association of prenatal antibiotics with foetal size and cord blood leptin and adiponectin

The effects of prenatal azithromycin exposure on offspring ovarian development at different stages, doses, and courses

Azithromycin, a commonly used macrolide antibiotic for treating chlamydial infections during pregnancy, has sparked investigations into its potential effects on offspring development. Despite these inquiries, there remains uncertainty about the specific impact of prenatal azithromycin exposure (PAzE) on offspring ovarian development and the precise "effect window". Pregnant mice, following clinical guidelines for azithromycin dosing, were orally administered azithromycin at different gestational stages [(gestational day, GD) 10-12 or GD 15-17], doses (50, 100, or 200 mg/kg·d), and courses (single or multiple). On GD 18, we collected offspring blood and ovaries to examine changes in fetal serum estradiol (E2) levels, fetal ovarian morphology, pre-granulosa cell function, and oocyte development. Multiple courses of PAzE resulted in abnormal fetal ovarian morphological development, disorganized germ cell nests, enhanced ovarian cell proliferation, and reduced apoptosis. Simultaneously, multiple courses of PAzE significantly increased fetal serum E2 levels, elevated ovarian steroidogenic function (indicated by Star, 3β-hsd, and Cyp19 expression), disrupted oocyte development (indicated by Figlα and Nobox expression), and led to alterations in the MAPK signal pathway in fetal ovaries, particularly in the high-dose treatment group. In contrast, a single course of PAzE reduced fetal ovarian cell proliferation, decreased steroidogenic function, and inhibited oocyte development, particularly through the downregulation of Mek2 expression in the MAPK signal pathway. These findings suggest that PAzE can influence various aspects of fetal mouse ovarian cell development. Multiple courses enhance pre-granulosa cell estrogen synthesis function and advance germ cell development, while a single terminal gestation dose inhibits germ cell development. These differential effects may be associated with changes in the MAPK signal pathway.

Exposures during pregnancy and at birth are associated with the risk of offspring eating disorders

BACKGROUND

Eating disorders (ED) are severe psychiatric disorders, commonly debuting early. Aberrances in the intrauterine environment and at birth have been associated with risk of ED. Here, we explore if, and at what effect size, a variety of such exposures associate with offspring ED, that is, anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS).

METHODS

This population-based cohort study, conducted from September 2021 to August 2023, used Finnish national registries of all live births in 1996-2014 (N = 1,097,753). Cox proportional hazards modeling was used to compare ED risk in exposed versus unexposed offspring, adjusting for potential confounders and performing sex-stratified analyses.

RESULTS

A total of 6614 offspring were diagnosed with an ED; 3668 AN, 666 BN, and 4248 EDNOS. Lower risk of offspring AN was seen with young mothers, continued smoking, and instrumental delivery, while higher risk was seen with older mothers, inflammatory disorders, prematurity, small for gestational age, and low Apgar. Offspring risk of BN was higher with continued smoking and prematurity, while lower with postmature birth. Offspring risk of EDNOS was lower with instrumental delivery, higher for older mothers, polycystic ovary syndrome, insulin-treated pregestational diabetes, antibacterial treatment, prematurity, and small for gestational age. Sex-specific associations were found.

CONCLUSIONS

Several prenatal and at birth exposures are associated with offspring ED; however, we cannot exclude confounding by maternal BMI. Nevertheless, several exposures selectively associate with risk of either AN, BN, or EDNOS, and some are sex-specific, emphasizing the importance of subtype- and sex-stratified analyses of ED.

PUBLIC SIGNIFICANCE

We define environmental factors involved in the development of different ED, of importance as preventive measure, but also in order to aid in defining the molecular pathways involved and thus in the longer perspective contribute to the development of pharmacological treatment of ED.

[Use of anti-bacterial agents in pregnant women before and after regulation in Brazil: Pelotas (Brazil) birth cohorts of 2004 and 2015]

Indiscriminate use of anti-bacterial agents during pregnancy can increase antimicrobial resistance and endanger both the mother's and the children's health. Currently, Brazil has the Collegiate Directive Resolution n. 20/2011, which controls prescription and dispensation of anti-bacterial agents. Given this scenario, this study compared the use of anti-bacterial agents by pregnant women participating in the 2004 and 2015 Pelotas (Brazil) birth cohorts, in Rio Grande do Sul, Brazil, considering the regulation issued between the two cohorts. Data were collected in the perinatal period of the two studies. The main outcome was the use of anti-bacterial agents during pregnancy. Prevalence scans were described based on independent variables and differences in percentage points (p.p.) between the two cohorts. The prevalence of anti-bacterial use was 41.9% (95%CI: 40.4; 43.3) in 2004 and 39.2% (95%CI: 37.7; 40.6) in 2015. Considering the pregnant women who reported having infection during pregnancy, a greater reduction in use was observed in 2015, when compared to 2004, in poor women (-15.4p.p., 95%CI: 9.59; 21.20) and in those who had less consultations (-17.1p.p., 95%CI: 2.81; 31.36). Considering total medications, the proportion of anti-bacterial used dropped from 20.6% (95%CI: 19.9; 21.4) in 2004 to 12.6% (95%CI: 12.1; 13.1) in 2015. The reductions found in both the prevalence of use and the proportion of anti-bacterial agents over total medications used may be a reflection of the regulatory policy implemented in 2011.

Prenatal environmental antibiotics and fetal and postnatal growth: A biomonitoring-based prospective study in Eastern China

Thus far, the effect of environmental antibiotics exposure to offspring's growth remains unclear. Here we aimed to evaluate whether and to what extent environmental antibiotics exposure is associated with fetal and postnatal growth. A total of 735 pregnant women and their full-term offspring from the Shanghai Obesity Birth Cohort were involved in the study. Maternal urine specimen was collected during the third trimester, and urinary concentration of fifteen environmental antibiotics was measured by liquid chromatography-tandem mass spectrometry and enzymatic method. Children were followed at birth, 12, 24 and 60 months, and growth parameters of the weight and height of children were recorded. Linear regression model was applied, and it was found that maternal veterinary antibiotic (VA) concentration was negatively associated with birth weight and ponderal index [per natural-logarithm (ln)-unit: adjusted β (95% confidence interval, CI) = - 42.1 (- 74.0, - 10.3) for birth weight, -0.11 (- 0.19, - 0.02) for birth weight z-score, and - 0.03 (- 0.05, - 0.002) for ponderal index]. Regarding specific VA, each ln-unit increment of florfenicol concentrations was likely to be associate with 39.7 g (95%CI: - 69.3, - 10.1) reduced birth weight, 0.10 (95%CI: - 0.18, - 0.02) reduced birth weight z-score, and 0.02 g/cm³ (95%CI: - 0.04, - 0.00) reduced ponderal index. Ciprofloxacin, a preferred-as-veterinary antibiotic, showed a similar dose-response relationship with neonatal anthropometric parameters to florfenicol. However, these adverse effects diminished as children grew up to 12-, 24- and 60-month-old. Larger prospective cohort studies and animal experiments are warranted to verify the hypothesis that environmental antibiotics exposure in early life, even at low doses, may cause fetal growth restriction.

Prenatal antibiotic exposure and birth weight

BACKGROUND/OBJECTIVES

Current research suggests an association between antibiotic use in early life and later obesity. Less is known about prenatal antibiotic exposure and foetal growth. We investigated the association between prenatal antibiotic exposure and birth weight.

METHODS

Data from the Danish National Birth Cohort were linked to the Danish National Medical Birth Registry. Exposure was self-reported antibiotic use in pregnancy. Outcome was registered birth weight. Multivariable linear regression models were adjusted for confounders defined a priori.

RESULTS

A total of 63 300 mother-child dyads from 1996 to 2002 were included. Overall, prenatal antibiotic exposure was not associated with birth weight (-8.90 g, 95%CI: -19.5- +1.64 g, p = 0.10). Findings were similar for those born term and preterm. Antibiotic exposure in second to third trimester, compared to no exposure, was associated with lower birth weight (-12.6 g, 95%CI: -24.1 to -1.1 g, p = 0.03). In sex-stratified analyses, there were no observed associations between antibiotics and birth weight. With further stratifications, prenatal antibiotic exposure and birth weight were associated in boys who were preterm (+91.0 g, 95%CI: +6.8 g- +175.2 g, p = 0.03) but not among girls who were preterm (-44.0 g, 95%CI: -128.1 to +40.0 g, p = 0.30).

CONCLUSIONS

Prenatal antibiotic exposure is not consistently associated with birth weight.

Prenatal exposure to antibiotics and risk of childhood overweight or obesity: A systematic review and meta-analysis

Infant antibiotic use has been modestly associated with childhood overweight, while evidence on prenatal exposures remains less clear. A systematic review and meta-analysis were conducted to examine associations between maternal antibiotic exposure and subsequent risk of childhood overweight/obesity. Publications were retrieved from PubMed and Web of Science databases up to December 2019. A random effects model was used to summarize risk estimates, overall, and by period and frequency of exposure. Ten observational studies were included in the narrative synthesis. We did not observe a clear pattern of association between prenatal antibiotic use and childhood overweight/obesity. There were suggestive associations for repeated exposures (≥3 courses) and those taking place during the second trimester of gestation, which were also pointed out in our meta-analysis (relative risk, RR_2T  = 1.15 (95% CI 1.04; 1.28, I²  = 18%), and RR_3courses  = 1.31 (95% CI 1.03; 1.67, I²  = 65%), respectively). In most studies, however, confounding by underlying infections cannot be ruled out. Overall, current data do not conclusively support the hypothesis that prenatal exposure to antibiotics is a risk factor for childhood obesity/overweight. Further studies, controlling for underlying infections and exploring the association according to frequency, period (both prenatal and intrapartum) and type of antibiotic, are needed to clarify this association.

Urinary antibiotic exposure across pregnancy from Chinese pregnant women and health risk assessment: Repeated measures analysis

Multiple antibiotics are widely used in clinic practice and livestock husbandry, but exposure data based on repeated measurements are scarce among pregnant women. Here, we biomonitored 41 antibiotics and their two metabolites in urine samples from 3235 pregnant women over three trimesters. Spearman's correlation coefficient, intraclass correlation coefficient (ICC), percentile analysis and linear mixed models were employed to evaluate the correlations, variability, co-exposure patterns and predictors of antibiotics, respectively. Pregnant urinary creatinine-adjusted concentrations of antibiotics were used to estimate daily exposure dose and assessed health risks. The target antibiotics were detected in more than 90% of urine samples, primarily as preferred as veterinary antibiotics (PVAs), and the 95th percentile urinary concentrations of each individual antibiotics were range from below the limits of detection to 5.74 ng/mL. We observed considerable within-subject variation (ICC: 0.05-0.63) of urinary antibiotics concentrations during pregnancy. More than half pregnant women were co-exposed to two or more antibiotics of different usage classes, while both co-exposure to high percentiles of three usage antibiotics at one trimester or exposure to single usage antibiotics at high-dose through three trimesters were infrequent in the study population, and most pregnant women were continuously exposed to low-dose PVAs across pregnancy. A total of 4.5% samples were showed hazard index values exceeding 1 during entire pregnancy. Urinary levels of antibiotics associated with residence, maternal age and education, pre-pregnancy BMI, household income and gestational week, especially vary by sampling seasons. Taken together, most pregnant women were frequently exposure to low-dose PVAs across pregnancy and some were in a health risk associated with the disturbance of gut microbiota. Multiple measurements of urinary antibiotic concentrations are essential to more accurate charactering the exposure levels during pregnancy. Several predictors of urinary antibiotics should be taken into consideration in future researches.

Prenatal exposure to antibiotics and timing of puberty in sons and daughters: A population-based cohort study

OBJECTIVE

To investigate if prenatal exposure to antibiotics is associated with earlier timing of pubertal development in sons and daughters.

STUDY DESIGN

This population-based cohort study is based upon the Puberty Cohort and includes a sample of 15,638 children born 2000-2003 in Denmark. Information on maternal use of antibiotics was collected around gestational week 30 and 6 months postpartum. The children were followed-up half-yearly from 11 years of age and throughout sexual maturation providing information on Tanner stages, acne and axillary hair, in addition to voice break and first ejaculation in sons and menarche in daughters. Due to the half-yearly collection of data on pubertal timing, the data was censored and therefore analysed using a multivariable censored time-to-event regression model. We examined both prenatal exposure to antibiotics at any time in pregnancy and trimester-specific prenatal exposure to antibiotics and pubertal timing, adjusting for maternal baseline socioeconomic and lifestyle characteristics. Mean age differences for the pubertal milestones between exposure groups were estimated. A combined estimate for overall pubertal timing was calculated based on combining all pubertal milestones into one model for sons and daughters, using Huber-White robust variance estimation which handles the risk of type 1 errors due to multiple testing of correlated outcomes. An active comparator approach with restriction to women reporting to have a urinary tract infection (cystitis) treated with either penicillin or sulfonamides was employed in a sub-analysis.

RESULTS

The prevalence of any maternal use of antibiotics in pregnancy was 21.1 %. There was no association between prenatal exposure to antibiotics and timing of pubertal development for the individual milestones. The adjusted combined estimate for pubertal timing in sons prenatally exposed to antibiotics at any point in pregnancy was -0.4 (95 % confidence interval (CI): -1.2; 0.4) months compared to unexposed sons. The adjusted combined estimate for pubertal timing in daughters prenatally exposed to antibiotics at any point in pregnancy was -0.1 (95 % CI: -0.9; 0.7) months compared to unexposed daughters. Both the trimester-specific analyses and the active comparator analysis revealed similar results.

CONCLUSION

Prenatal exposure to antibiotics was not associated with pubertal timing.

Childhood inflammatory and metabolic disease following exposure to antibiotics in pregnancy, antenatally, intrapartum and neonatally

Background: There are concerns that the use of antibiotics before, during or immediately after pregnancy may have adverse effects on the neonatal gut microbiome and adversely affect the development of the infant immune system, leading to the development of childhood allergy, asthma, atopic disease and obesity. Methods: In this narrative review, we have explored a number of hypotheses, including the "Barker hypothesis", the "hygiene hypothesis", the link between inflammation and metabolic disease, and the influence of the neonatal gut microbiota on the development of the immune system in infants. Results: We found evidence to link the use of antibiotics before, during or immediately after pregnancy with an increased risk of childhood allergy, asthma, atopy and obesity. Conclusions: Although we found robust evidence to link antibiotic use in pregnancy with obesity and an "allergic triad" of asthma, eczema and hay fever, care must be taken when interpreting the findings because of the lack of adjustment for confounding variables in published studies. These may be (i) whether or not the mother had the same outcome variable (for example, asthma) as the infant, for which the mother may have received the antibiotics; (ii) the indication, timing or number of antibiotic courses given; (iii) the use of broad-spectrum or narrow-range antibiotics; (iv) the dose-dependent nature of the effector; and (v) the class of antibiotics used.

Association of prenatal antibiotics with measures of infant adiposity and the gut microbiome

BACKGROUND

Prenatal antibiotic exposure has been associated with an altered infant gut microbiome composition and higher risk of childhood obesity, but no studies have examined if prenatal antibiotics simultaneously alter the gut microbiome and adiposity in infants.

METHOD

In this prospective study (Nurture: recruitment 2013-2015 in North Carolina, United States), we examined in 454 infants the association of prenatal antibiotic exposure (by any prenatal antibiotic exposure; by trimester of pregnancy; by number of courses; by type of antibiotics) with infant age- and sex-specific weight-for-length z score (WFL-z) and skinfold thicknesses (subscapular, triceps, abdominal) at 12 months of age. In a subsample, we also examined whether prenatal antibiotic exposure was associated with alterations in the infant gut microbiome at ages 3 and 12 months.

RESULTS

Compared to infants not exposed to prenatal antibiotics, infants who were exposed to any prenatal antibiotics had 0.21 (95% confidence interval [CI] 0.02, 0.41) higher WFL-z at 12 months, and 0.28 (95% CI 0.02, 0.55) higher WFL-z if they were exposed to antibiotics in the second trimester, after adjustment for potential confounders, birth weight, and gestational age. We also observed a dose-dependent association (P-value for trend = 0.006) with infants exposed to ≥ 3 courses having 0.41 (95% CI 0.13, 0.68) higher WFL-z at 12 months. After further adjustment for delivery method, only second-trimester antibiotic exposure remained associated with higher infant WFL-z (0.27, 95% CI 0.003, 0.54) and subscapular skinfold thickness (0.49 mm, 95% CI 0.11, 0.88) at 12 months. Infants exposed to second-trimester antibiotics versus not had differential abundance of 13 bacterial amplicon sequence variants (ASVs) at age 3 months and 17 ASVs at 12 months (false discovery rate adjusted P-value < 0.05).

CONCLUSIONS

Prenatal antibiotic exposure in the second trimester was associated with an altered infant gut microbiome composition at 3 and 12 months and with higher infant WFL-z and subscapular skinfold thickness at 12 months.

The role of antimicrobial treatment during pregnancy on the neonatal gut microbiome and the development of atopy, asthma, allergy and obesity in childhood

INTRODUCTION

The use of antibiotics prenatally, during pregnancy, or neonatally may have adverse effects on the neonatal gut microbiome, and adversely affect the development of the infant immune system, leading to childhood atopy, asthma, allergy and obesity.

AREAS COVERED

Vaginal eubiosis and dysbiosis from molecular-based, cultivation-independent techniques, and how this affects the neonatal gut microbiome and early development of the immune system, the association between maternal antibiotics and the beneficial role of vitamin D in the development of atopy, asthma, allergy and obesity, efforts to reduce the use of antibiotics in pregnancy and therapeutic interventions such as vaginal 'seeding', probiotics, breastfeeding and neonatal dietary supplementation.

EXPERT OPINION

Currently available research gives insufficient attention to confounding variables. There remains uncertainty as to whether it is relevant that the mother suffered from the same condition as the purported infant outcome variable, for which she may have received antibiotics. In most studies, there is a lack of control for the number of antibiotic courses administered, the timing of use, the use of broad spectrum or narrow range antibiotics, the indication for antibiotics, the dose-dependent nature of the effect, the class of antibiotics used, or a varying degree of risk.

Determination of antibiotic concentration in meconium and its association with fetal growth and development

BACKGROUND

The association between antibiotic use during pregnancy and neonatal birth outcomes has received considerable attention. Most of the previous assessment of antibiotic exposure during pregnancy relied on questionnaires and clinical prescriptions, and very few studies examined pregnancy exposure to antibiotics using human biomonitoring data.

OBJECTIVE

To explore the association between the cumulative exposure of antibiotics during the whole pregnancy and neonatal birth measurements using biomonitoring data of antibiotics in meconium.

METHODS

Three hundred and sixty nine pregnant women within the Maternal Psychological and Environmental Assessments of Kids Cohort Study were randomly selected into this study. Eighteen common antibiotics of six categories (six β‑lactams, three tetracyclines, four sulfonamides, one phenicols, one lincosamides and three fluoroquinolones) were selected as the target antibiotics in meconium. The measurement was conducted by ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry platform. Neonatal birth measurements were obtained from the medical records. Multiple linear regression models were used to examine the associations of antibiotic exposure with neonatal birth outcome (birth weight, birth length) and placental growth indicators (placental surface area, placental weight). Logistic regressions were used to evaluate associations with small for gestational age (SGA) and large for gestational age (LGA).

RESULTS

Twelve of the eighteen antibiotics were found in 62.1% of the meconium, with detection rates ranging from 0.3% to 43.9%. The three antibiotics with the highest detection rates were chlortetracycline (43.9%), penicillin (16.5%) and chloramphenicol (10.8%), respectively. The highest antibiotic concentration among detected antibiotics was penicillin (24,243.15 μg/kg). The concentration of penicillin was positively associated with the birth weight (β: 0.025; 95% CIs: 0.003-0.047). A significant positive association was also observed between the concentration of chlortetracycline and the placental surface area (β: 2.559; 95% CIs: 0.296-4.822). These associations were sex related and mainly observed in female newborns. Exposure to penicillin was also found to be associated with increased risk of LGA, which was consistent with changes in birth weight.

CONCLUSIONS

Pregnancy exposure to certain antibiotics was associated with altered fetal growth and development, which may affect the normal growth trajectory of infants and children in later life.

Newborn adipokines and early childhood growth

BACKGROUND

While adipokines can regulate satiety and energy metabolism, whether they are associated with childhood growth is unclear.

OBJECTIVE

To evaluate whether adipokine levels at birth are associated with growth.

METHODS

A total of 2264 singletons and 1144 twins from Upstate KIDS (born 2008-2010) had adiponectin, leptin, resistin and complement factor D measured in newborn blood spots. Parents reported anthropometry from paediatric visits via questionnaires every 4-6 months. Generalized linear mixed effects models were used to estimate growth trajectories through 3 years of age.

RESULTS

Among singletons, resistin and leptin were associated with greater weight-for-age (0.12 z-score units (95%CI: 0.04, 0.20) [p = 0.003] and 0.15 (0.06, 0.24) [p = 0.001], respectively) and BMI z-score (0.11; 0.02, 0.20 [p = 0.02] and 0.18; 0.07, 0.28 [p = 0.002], respectively). After adjusting for birthweight, resistin and a ratio of resistin-to-adiponectin remained associated with weight through 3 years of age and odds of being overweight at 3 years of age in a subgroup of singletons. Among twins, adiponectin was associated with increased weight-for-age and length-for-age z-scores even after adjusting for birthweight (0.18; 0.08, 0.28 [p = 0.0006]; 0.20; 0.07, 0.33 [p = 0.003], respectively).

CONCLUSIONS

Levels of adipokines were associated with early childhood growth in small magnitudes. Resistin may be relevant for further examination in paediatric obesity.

Prenatal antimicrobial use and early-childhood body mass index

BACKGROUND/OBJECTIVES

Growing evidence suggests that antibiotic use is associated with childhood body mass index (BMI), potentially via mechanisms mediated by gut microbiome alterations. Less is known on the potential role of prenatal antimicrobial use in offspring obesity risk. We examined whether prenatal antibiotic or antifungal use was associated with BMI at the age of 2 years in 527 birth cohort participants.

METHODS/SUBJECTS

Antimicrobial use was obtained from the prenatal medical record. Height and weight were measured at the age of 2 years. Overweight/obesity was defined as a BMI ⩾85^th percentile.

RESULTS

A total of 303 (57.5%) women used antibiotics and 101 (19.2%) used antifungals during pregnancy. Prenatal antifungal use was not associated with child BMI at the age of 2 years. In the fully adjusted model, prenatal antibiotic use was associated with a 0.20±0.10 (P=0.046) higher mean BMI Z-score at the age of 2 years. Associations between prenatal antibiotic use and childhood BMI varied by trimester of exposure, with first or second-trimester exposure more strongly associated with larger BMI at the age of 2 years for both BMI Z-score (interaction P=0.032) and overweight/obesity (interaction P=0.098) after covariate adjustment.

CONCLUSIONS

Prenatal antibiotic, but not antifungal, use is associated with larger BMI at the age of 2 years; associations were stronger for antibiotic exposures in earlier trimesters. Future studies examining whether these associations are due to alterations in the maternal and/or infant microbiome are necessary. Children who are overweight at the age of 2 years are at higher risk for being overweight as they age; prenatal antibiotic use is a potentially modifiable exposure that could reduce childhood obesity.