The impact of advanced maternal age on pregnancy and offspring health: A mechanistic role for placental angiogenic growth mediators

The impact of maternal age and body mass index on hypertensive disorders of pregnancy: Moving beyond the cut-off effect

OBJECTIVES

Maternal age (MA) and body mass index (BMI) are known risk factors for hypertensive disorders of pregnancy (HDP). Different threshold values are used to calculate preeclampsia risk scores, but the appropriateness of a cut point model has not been extensively evaluated. This is because the effects of both MA and BMI occur continuously. We aimed to investigate the relationship between MA, BMI, and HDP, respecting the continuous nature of the two independent variables.

STUDY DESIGN

We retrospectively selected all nulliparous women with singleton pregnancies who delivered after 22 gestational weeks from January 2005 to December 2019 (25,165 women). We used univariate and multivariable logistic regression analyses implementing linear, quadratic, cubic, and penalized splines functions to test, investigate, and describe the relationship between continuous BMI, continuous MA, and risk of HDP.

MAIN OUTCOME MEASURES

MA, BMI, and infertility treatments are independently associated with the risk of developing all HDP in nulliparous women. The impacts of MA and BMI on the risk of developing HDP occur gradually, and penalized splines functions resulted in the best model to describe these associations with a different model for each HDP. No interaction factors were retained between MA, BMI, and infertility treatments.

CONCLUSIONS

Given the relevance of HDP on maternal mortality, an accurate identification of women at increased risk of developing the disease is crucial. In an era where technology is rapidly advancing, new models for customized risk assessment of HDP, considering the continuous nature of MA and pregestational BMI, must be implemented.

Fetal macrosomia and its associated factors among pregnant women delivered at national referral hospital in Uganda, a case-control study

BACKGROUND

The delivery of macrosomic newborns (newborns>4000gm) is increasing steadily worldwide and yet it is associated with many complications. The risk factors for fetal macrosomia include weight at first antenatal visit, previous delivery of a large newborn, newly diagnosed diabetes in pregnancy, increasing number of deliveries, a male fetus, and many others. There is paucity of data on fetal macrosomia in Uganda and the objective of this study therefore was to determine the risk factors for fetal macrosomia among women who delivered at a National Referral Hospital in Kampala, Uganda..

METHODS

An unmatched case-control study was conducted among 177 cases and 354 controls at Kawempe National Referral Hospital. Data was collected using interviewer-administered questionnaires for three months from 8th February 2021-25th May 2021. Comparison between the cases and the controls was done using the student t-test for normally distributed continuous data. The Mann Whitney U Test (Wilcoxon Rank Sum Test) was used to compare data that was not normally distributed. Binary logistic regression was used in bivariate and multivariate analysis for factors associated with fetal macrosomia using STATA version 16.0.

RESULTS

A total of 531 participants were recruited into the study in a ratio of one case to two controls. The mean age for cases was 28.5 ± 5.9 years and 25.9 ± 5.4 years for controls while the mean weight was 78.4 ± 12.4Kgs for cases and 68.2 ± 11.7 Kg for controls. Risk factors for fetal macrosomia included maternal age ≥40 years (aOR = 7.4, [95%CI 1.37-39.44], p value = 0.020), maternal weight ≥80 kg (aOR = 4.0, [95%CI 2.15-7.40], p value <0.001), maternal height ≥160 cm (aOR = 1.6, [95%CI 1.02-2.51], p value = 0.040), being married (aOR = 2.55, [95%CI 1.08-6.06], P value = 0.038), gestation age ≥40 weeks (aOR = 1.8,[95%CI 1.16-2.82], p value = 0.009), previous macrosomia (aOR = 2.2, [95%CI 1.26-3.81], p value = 0.006) and male babies (aOR = 1.78, [95%CI 1.14-2.77], p value = 0.011).

CONCLUSIONS

The main risk factors for fetal macrosomia were higher maternal weight and height, advanced age as well as post-datism, previous delivery of a large newborn, male fetus and being in a marital relationship. A well-designed protocol to identify women with risk factors for fetal macrosomia may help to provided targeted interventions in this group.

Genetic and audiological determinants of hearing loss in high-risk neonates

OBJECTIVE

We aimed to investigate the correlation between prevalent risk factors for high-risk neonates in neonatal intensive care unit and their hearing loss, and to examine the audiological features and genetic profiles associated with different deafness mutations in our tertiary referral center. This research seeks to deepen our understanding of the etiology behind congenital hearing loss.

METHODS

We conducted initial hearing screenings, including automated auditory brainstem response, distortion product otoacoustic emission, and acoustic immittance on 443 high-risk neonates within 7 days after birth and 42 days (if necessary) after birth. Neonates who failed initial screenings underwent further diagnostic tests at 3 months. The risk factors were analyzed retrospectively by Chi-Square test and stepwise logistic regression. Genetic analysis involved a deafness sequencing panel targeting 19 pathogenic variants across four genes (GJB2, GJB3, SLC26A4, and MT-RNR), applied to both the study cohort and a larger hearing screening cohort of 14863 neonates from our center and different medical centers in the same region.

RESULTS

Out of the 443 high-risk neonates, 222 failed their diagnostic hearing tests. Logistic regression identified preterm birth, neonatal hyperbilirubinemia and advanced maternal age (≧35 yr) as significant risk factors for hearing loss. Genetic screening of 33 neonates who failed the diagnostic tests revealed that 7 (21.21%) carried at least one pathogenic variant, with identified 1 homozygotes and 3 heterozygotes in the GJB2, 1 homozygotes and 1 heterozygotes in the SLC26A4 gene, and 1 homoplasmic variant in the MT-RNR (12SrRNA). In the larger hearing screening cohort, 497 (3.34%) were genetically positive for deafness mutations, among whom 29 had the diagnostic hearing tests and 7 eventually diagnosed with hearing loss. Of the rest 468 neonates who didn't have the diagnostic tests, 445 (95.09%) passed the hearing screening tests.

CONCLUSION

Preterm birth, neonatal hyperbilirubinemia and advanced maternal age are critical risk factors for hearing impairment in high-risk neonates. Mutations such as c.235delC in GJB2 and c.919-2A>G in SLC26A4 are the most common. Long-term follow-up of neonates carrying heterozygous variants, particularly in genes like GJB3, is necessary to understand their progression and hearing outcomes. This study highlights the importance of deafness gene screening in neonates to ensure accurate diagnosis and effective intervention.

LEVEL OF EVIDENCE

Level 3.

Effect of advanced maternal age on ischemic stroke vulnerability in aged rats: Investigating on blood-brain barrier permeability and gene expression

Background

Advanced maternal age (AMA), commonly defined as pregnancy at or above 35 years old. Based on the evidence, this trend has raised concerns about potential health consequences for mothers, particularly in relation to ischemic stroke. Studies suggest that AMA may be associated with a higher risk of ischemic stroke in women due to physiological changes that impact vascular health and increase cardiovascular risk factors. The aim of this study was to investigate the effect of AMA on the extent of damage after ischemic stroke in aged rats.

Methods

Female rats that gave birth at an old age (10 months) and at a young age (4 months) were subjected to ischemic stroke in old age (20 months) and subsequently compared.We assessed neurological deficits, infarct volume, blood-brain barrier (BBB) permeability, TNF-alpha levels, total oxidant capacity, and gene expressions that play a role in BBB integrity (VEGF, Occludin, and MMP-9) following ischemic stroke.

Results

There were significantly elevated levels of MMP-9 expression and reduced levels of occludin in AMA rats. Additionally, AMA rats had significantly higher levels of TNF-alpha and total oxidant capacity after experiencing an ischemic stroke. AMA rats showed significantly higher brain water content (BBB permeability), infarct volume, and neurological deficits compared to young-aged pregnancies.

Discussion

Complex relationship between pregnancy-related physiological changes, aging, vascular gene expression, and inflammatory factors may play a role in the increased vulnerability observed in older pregnant rats. The similarities between pregnancy-related alterations and aging highlight the influence of advanced maternal age on susceptibility to ischemic stroke.

A genetically small fetus impairs placental adaptations near term

The placenta is a gatekeeper between the mother and fetus, adapting its structure and functions to support optimal fetal growth. Studies exploring adaptations of placentae that support the development of genetically small fetuses are lacking. Here, using a mouse model of impaired fetal growth, achieved by deleting insulin-like growth factor 2 (Igf2) in the epiblast, we assessed placental nutrient transfer and umbilical artery (UA) blood flow during late gestation. At embryonic day (E) 15.5, we observed a decline in the trans-placental flux of glucose and system A amino acids (by using 3H-MeG and 14C-MeAIB), proportionate to the diminished fetal size, whereas UA blood flow was normal. However, at E18.5, the trans-placental flux of both tracers was disproportionately decreased and accompanied by blunted UA blood flow. Feto-placental growth and nutrient transfer were more impaired in female conceptuses. Thus, reducing the fetal genetic demand for growth impairs the adaptations in placental blood flow and nutrient transport that normally support the fast fetal growth during late gestation. These findings have important implications for our understanding of the pathophysiology of pregnancies afflicted by fetal growth restriction.

Incidence of New Asthma in Pregnancy and Associated Risk Factors: A 10-Year Nationwide Population-Based Study

Pregnancy is a risk factor for asthma exacerbation and may trigger new-onset asthma in nonasthmatics. This study evaluated the epidemiology of newly diagnosed asthma during pregnancy and the associated risk factors among previously nonasthmatic women. Twelve-year medical data from the Korean National Health Insurance claims database (from January 2007 to December 2018) of Korean women who gave birth between January 2012 and December 2015 were collected. Previously nonasthmatic women were defined as those who had not been diagnosed with asthma for at least 4 years before pregnancy. Asthma flare-up was defined as asthma diagnosed three times or more and treated at least once with an oral corticosteroid. A nested case-control study was performed, and then the derived risk factors were applied to whole study population. Among the nonasthmatic women, 7.5% experienced asthma during pregnancy including episodes requiring hospitalization and 18.6% of them visited emergency room. Older age, primiparity, multi-fetal pregnancy, and rhinitis were identified as the risk factors. Among the entire study population, moderate to severe rhinitis was a significant risk factor across all age groups, while primiparity with multi-fetal pregnancy was one for older pregnant women; 22.7% in those ≥ 34 years old experienced asthma flare-ups compared to only 3.5% in the < 34 age group. A substantial portion of pregnant women with no history of asthma experienced an asthma flare-up during pregnancy. Multi-fetal pregnancy as primiparity at a later age and moderate to severe rhinitis are risk factors for the new development of asthma.

Association between maternal age and sex-based neonatal free triiodothyronine levels

BACKGROUND

Advanced maternal age may affect the intrauterine environment and increase the risk of neurodevelopmental disorders in offspring. Thyroid hormones are critical for fetal neurological development but whether maternal age influences fetal thyroid hormone levels in euthyroid mothers is unknown.

OBJECTIVE

This study evaluated the association between cord blood thyroid hormones and maternal age, fetal sex, maternal thyroid function, and other perinatal factors.

METHODS

The study population consisted of 203 healthy women with term singleton pregnancies who underwent elective cesarean section. Maternal levels of free T3 (fT3), free T4 (fT4) and TSH before delivery, and cord levels of fT3, fT4 and TSH were measured. Spearman's correlation coefficient and multiple linear regression analyses were performed to determine the correlation between cord thyroid hormone parameters and maternal characteristics.

RESULTS

There were no significant differences in maternal serum or cord blood thyroid hormone levels between male and female births. In multivariate linear regression analysis, maternal age and maternal TSH values were negatively associated with the cord blood levels of fT3 in all births, after adjusting for confounding factors. Maternal age was more closely associated with the cord blood levels of fT3 in female than in male births.

CONCLUSION

The inverse association between maternal age and cord blood levels of fT3 in euthyroid pregnant women suggested an impact of maternal aging on offspring thyroid function.

Paternal high-fat diet altered H3K36me3 pattern of pre-implantation embryos

The global transition towards diets high in calories has contributed to 2.1 billion people becoming overweight, or obese, which damages male reproduction and harms offspring. Recently, more and more studies have shown that paternal exposure to stress closely affects the health of offspring in an intergenerational and transgenerational way. SET Domain Containing 2 (SETD2), a key epigenetic gene, is highly conserved among species, is a crucial methyltransferase for converting histone 3 lysine 36 dimethylation (H3K36me2) into histone 3 lysine 36 trimethylation (H3K36me3), and plays an important regulator in the response to stress. In this study, we compared patterns of SETD2 expression and the H3K36me3 pattern in pre-implantation embryos derived from normal or obese mice induced by high diet. The results showed that SETD2 mRNA was significantly higher in the high-fat diet (HFD) group than the control diet (CD) group at the 2-cell, 4-cell, 8-cell, and 16-cell stages, and at the morula and blastocyst stages. The relative levels of H3K36me3 in the HFD group at the 2-cell, 4-cell, 8-cell, 16-cell, morula stage, and blastocyst stage were significantly higher than in the CD group. These results indicated that dietary changes in parental generation (F0) male mice fed a HFD were traceable in SETD2/H3K36me3 in embryos, and that a paternal high-fat diet brings about adverse effects for offspring that might be related to SETD2/H3K36me3, which throws new light on the effect of paternal obesity on offspring from an epigenetic perspective.

Histologic chorioamnionitis in extremely preterm births, microbiological findings and infant outcome

BACKGROUND

Histologic chorioamnionitis (HCA) is most often caused by ascending bacterial infection originating from the cervicovaginal tract.

OBJECTIVES

To investigate whether HCA with a fetal inflammatory response (FIR) has a worse clinical outcome than HCA alone. Further, if FIR or a positive maternal microbiologic culture obtained prior to birth were related to adverse neonatal outcomes in a cohort of extremely preterm (EP) neonates.

METHODS

Prospective observational cohort study recruiting EP singleton pregnancies (gestational age at birth ≤28 weeks) with confirmed HCA. FIR was defined by fetal neutrophils in the chorionic vessels and/or umbilical vessels. Positive culture was defined as growth of potentially pathogenic bacteria in a sample from the cervicovaginal tract prior to birth, or if a cervicovaginal culture was lacking, a culture result from the placenta was used. Logistic regression was used to estimate odds ratios and 95% confidence intervals for the associations between FIR, a positive culture result and adverse outcomes, defined as bronchopulmonary dysplasia (BPD), brain pathology assessed by magnetic resonance imaging, retinopathy of prematurity, necrotizing enterocolitis, early-onset neonatal sepsis, and perinatal death. A composite outcome variable included one or more adverse outcomes.

RESULTS

We included 71 cases with HCA, of which 51 (72%) had FIR. Maternal age, rate of clinical chorioamnionitis (CCA), preterm pre-labor rupture of membranes (PPROM), the number of women receiving antenatal steroids and antibiotics, and the rate of positive maternal cultures of potentially pathogenic bacteria were all significantly higher in the HCA with FIR. Neonates in the FIR group had significantly higher levels of blood leukocytes compared to those without. FIR was associated with a longer interval from PPROM to delivery (log-rank test: p = .022). Microbiological sampling had been performed in 63 (89%) cases, of which 60 (95%) were cervicovaginal samples. No associations were found between a positive culture and adverse neonatal outcomes, in contrast to FIR, that was significantly associated to BPD and brain pathology.

CONCLUSIONS

In a cohort of EP pregnancies with confirmed HCA, the presence of FIR was associated with advanced maternal age, CCA, PPROM, antenatal steroids and antibiotics, and a positive maternal culture of potentially pathogenic bacteria. However, the presence of FIR, and not a positive culture, was associated with adverse neonatal outcomes.

Fetal abdominal obesity and the ensuing adverse perinatal outcomes in older obese pregnant women with or without obesity and with normal glucose tolerance

To investigate whether the increased risk of fetal abdominal obesity (FAO) is present in the older (≥ 35 years) and/or obese (≥ body mass index 25 kg/m2) women with normal glucose tolerance, we reviewed medical record of 6721 singleton pregnancy. At 24-28 gestational weeks (GW), fetal abdominal overgrowth was assessed by the fetal abdominal overgrowth ratios (FAORs) of the ultrasonographically estimated gestational age (GA) of abdominal circumference per actual GA by the last menstruation period, estimated GA of biparietal diameter or femur length, respectively. FAO was defined as FAOR ≥ 90th percentile. Compared to young and non-obese women, older women showed significantly higher FAORs irrespective of obesity and the prevalence of FAO in older and non-obese women was significantly higher (11.8% vs. 8.6%, p < 0.05). The odds ratio for large for gestational age at birth were 3.06(1.96-4.77, p < 0.005), 1.47(1.16-1.86, p < 0.005) and 2.82(1.64-4.84, p < 0.005) in young and obese, older and non-obese, and older and obese women, respectively. The odds ratio for primary cesarean delivery in older and non-obese women was 1.33 (1.18-1.51, p < 0.005). An increased risk of FAO at 24-28 GW and subsequent adverse perinatal outcomes have been observed in the older women with or without obesity, compared to younger and non-obese women, despite normal glucose tolerance.

Advanced Maternal Age Among Nulliparous at Term and Risk of Unscheduled Cesarean Delivery

BACKGROUND

With the rise in the number of women giving birth at an advanced age, the association between advanced maternal age and adverse obstetrical outcomes is a growing concern in developed countries. Despite the well-established link between advanced maternal age and pregnancy-related complications, there has been limited research examining the specific risks related to unscheduled cesarean delivery in nulliparas at term.

OBJECTIVE

This study aimed to evaluate the risks associated with unscheduled cesarean delivery in nulliparas at ≥37 weeks of gestation, comparing the outcomes of younger patients with those aged ≥40 years.

STUDY DESIGN

This retrospective cohort study was conducted in a tertiary maternity hospital in Switzerland (high-income country). The study included nulliparas who delivered a live-born infant at ≥37 weeks between January 2015 and December 2019. We excluded pregnant women who had a planned cesarean delivery, were aged <18 years, multiparous, delivered before 37 weeks of gestation, or had pregnancies that ended in stillbirth. Participants were divided into 2 age groups: (1) ≥40 years and (2) <40 years. The primary outcome was the incidence of unscheduled cesarean delivery. Its association with advanced maternal age was evaluated after adjusting for confounding factors by multivariate logistic regression, expressed as an adjusted odds ratio. Secondary outcomes included pregnancy outcomes and neonatal outcomes.

RESULTS

A total of 5211 patients were included: 173 in the ≥40-years (advanced maternal age) group and 5038 in the <40-years (non-advanced maternal age) group; 26.01% (95% confidence interval, 19.65-33.22; n=45) of women in the advanced maternal age group had an unscheduled cesarean delivery, whereas 15.26% (95% confidence interval, 14.28-16.29; n=769) of women in the non-advanced maternal age group underwent the procedure. Advanced maternal age was associated with unscheduled cesarean delivery, with an adjusted odds ratio of 1.51 (95% confidence interval, 1.06-2.17; P=.024). Among vaginal deliveries, assisted procedures were performed on 29.7% (95% confidence interval, 21.9-38.4; n=38) of advanced maternal age patients vs 20.1% (95% confidence interval, 18.9-21.3; n=856) of non-advanced maternal age patients. Postpartum blood loss >1000 mL occurred in 5.8% (95% confidence interval, 2.8-10.4; n=10) of advanced maternal age patients and 3.1% (95% confidence interval, 2.6-3.6; n=156) of non-advanced maternal age patients.

CONCLUSION

Advanced maternal age is associated with increased risk of unscheduled cesarean delivery among nulliparas. This provides healthcare professionals with confirmation that advanced age may represent an individual risk factor, suggesting that nulliparous patients aged over 40 years may benefit from improved information regarding the factors contributing to this pregnancy outcome.

Relationship between age of pregnant women with gestational diabetes mellitus and mode of delivery and neonatal Apgar score

BACKGROUND

Gestational diabetes mellitus (GDM) refers to abnormal glucose tolerance during pregnancy, and it is often accompanied by obvious changes in glucose and lipid metabolism, and associated with adverse pregnancy outcomes. The incidence of fetal distress, polyhydramnios, puerperal infection, premature delivery, and macrosomia in pregnant women with GDM are higher than in those without GDM.

AIM

To analyze the relationship between age of pregnant women with GDM and mode of delivery and neonatal Apgar score.

METHODS

A total of 583 pregnant women with GDM who delivered in the Department of Obstetrics at our hospital between March 2019 and March 2022 were selected. Among them, 377 aged < 35 years were selected as the right age group and 206 aged > 35 years were selected as the older group. The clinical data of the two groups were collected, and the relationship between age of the pregnant women with GDM and mode of delivery, maternal and neonatal outcomes, and neonatal Apgar score were compared. In the older group, 159 women were classed as the adverse outcome group and 47 as the good outcome group according to whether they had adverse maternal and infant outcomes. The related factors of adverse maternal and infant outcomes were analyzed through logistic regression.

RESULTS

The number of women with assisted pregnancy, ≤ 37 wk gestation, ≥ 2 pregnancies, one or more deliveries, and no pre-pregnancy blood glucose screening in the older group were all higher than those in the right age group (P < 0.05). The natural delivery rate in the right age group was 40.85%, which was higher than 22.33% in the older group (P < 0.05). The cesarean section rate in the older group was 77.67%, which was higher than 59.15% in the right age group (P < 0.05). The older group had a higher incidence of polyhydramnios and postpartum hemorrhage, and lower incidence of fetal distress than the right age group had (P < 0.05). There was no significant difference in neonatal weight between the two groups (P > 0.05). The right age group had higher Apgar scores at 1 and 5 min than the older group had (P < 0.05). Significant differences existed between the poor and good outcome groups in age, education level, pregnancy mode, ≤ 37 wk gestation, number of pregnancies, and premature rupture of membranes (P < 0.05). Logistic regression showed that age, education level and premature rupture of membranes were all risk factors affecting the adverse outcomes of mothers and infants (P < 0.05).

CONCLUSION

Delivery mode and Apgar score of pregnant women with GDM are related to age. Older age increases the adverse outcome of mothers and infants.