Category: Obstetrics & Gynaecology

Study Confirms Analgesics during Pregnancy Carries Risks for Newborns

Pregnant with ultrasound image
Source: Pixabay

Researchers have called for a reassessment of medical advice on analgesic use during pregnancy after a new study published in BMJ Open found that pregnant women using over-the-counter analgesics are about 1.5 times more likely to have a baby with health issues.

The study found elevated risks for preterm delivery, stillbirth or neonatal death, physical defects and other problems compared with the offspring of mothers who did not take such medications.

Between 30% and 80% of women globally use non-prescription analgesics in pregnancy for pain relief. However, there is presently great variation in evidence for safety of use during pregnancy, with some drugs considered safe and others not.

“We would encourage a strong reinforcement of the official advice for pregnant women.”

Aikaterini Zafeiri, first author of the study

The study analysed data from more than 151 000 pregnancies over 30 years (1985–2015) which contained medical notes for non-prescribed maternal consumption of five common analgesic. These were paracetamol, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac, naproxen and ibuprofen – either as single compounds or in combinations.

Overall, 29% of women have taken over-the-counter analgesics during pregnancy, a figure which more than doubled to 60% during the last seven years of the 30-year study period.

When asked specifically at their first antenatal clinic visit, as opposed to later in pregnancy or after labour, 84% of women using painkillers reported use during the first 12 weeks after conception. However, the duration and dose of use and medical reason for use were not recorded.

Nevertheless, given that up to 60% of women reported using over the counter analgesics, they could not all have underlying medical conditions that would cause the increased risks seen in this study.

The study found increases in the following:

  • Neural tube defects: 64% more likely.
  • Admission to a neonatal unit: 57% more likely.
  • Neonatal death: 56% more likely.
  • Premature delivery before 37 weeks: 50% more likely.
  • Baby’s condition at birth based on APGAR score of less than 7 at five minutes: 48% more likely.
  • Stillbirth: 33% more likely.
  • Birthweight under 2.5 kg: 28% more likely.
  • Hypospadias, a birth defect affecting the penis: 27% more likely.

First author of the paper, Aikaterini Zafeiri of the University of Aberdeen said: “In light of the study findings, the ease of access to non-prescription painkillers, in combination with availability of mis-information as well as correct information through the internet, raises safety concerns.

“This is especially when mis-informed or partially-informed self-medication decisions are taken during pregnancy without medical advice.

“It should be reinforced that paracetamol in combination with NSAIDs is associated with a higher risk and pregnant women should always consult their doctor or midwife before taking any over-the-counter drugs. We would encourage a strong reinforcement of the official advice for pregnant women.”

Source: University of Aberdeen

No Added Seizure Risk from Antidepressant Use in Pregnancy

Pregnant with ultrasound image
Source: Pixabay

A large Swedish study in the journal Neurology found that pregnant women taking selective serotonin reuptake inhibitors (SSRIs) or selective norepinephrine reuptake inhibitors (SNRIs) during the first trimester of was not linked to an increased risk for neonatal seizures and epilepsy in childhood.

Any increase in seizures or epilepsy is likely due to other factors, the researchers said.

“It’s not likely the medications themselves that are causing the seizures and epilepsy in children, but rather the reasons why these women are taking the medication,” according to Kelsey Kathleen Wiggs, a PhD candidate at Indiana University in Bloomington. There are also the other background factors that differ between women who do and do not use SSRI/SNRIs.

“When it rains, it pours,” Wiggs said. “Women who are taking antidepressants in pregnancy are doing that for lots of different reasons, and they might be at risk for different things than women who aren’t taking those medications in pregnancy.”

An elevated risk for neonatal seizures (risk ratio [RR] 1.41) and epilepsy in early childhood (HR 1.21) among offspring of mothers who used antidepressants in pregnancy.

Adjustment for maternal indications for SSRI/SNRI use and background factors like smoking during pregnancy revealed that they were drivers for both associations: neonatal seizures (RR 1.10); epilepsy diagnosis at 5 years (HR 0.96). Parental history of epilepsy was not found to affect the association.

The findings provide a “conclusive answer” to these concerns with using SSRI/SNRIs during pregnancy, according to Anne Berg, PhD, and Torin Glass, BM, Bch, BAO.

“[SSRI/SNRIs] have been demonstrated to have serotonergic central nervous system effects and are associated with an observable withdrawal syndrome which may be seen in the neonate following in utero exposure,” noted Drs Berg and Glass, in an accompanying editorial.

“The authors understood that with a population-based data registry and huge sample size, they had more than sufficient statistical power to detect even a modest increase in risk,” the editorialists wrote. “They tested this hypothesis and were able to reject it, definitively!”

In order to determine whether antidepressants had a causal association with infant seizures and childhood epilepsy, the researchers analysed data from national Swedish healthcare registries on a total of 1 721 274 children in Sweden born between 1996 and 2011.

Participants were divided into two groups: one group of mothers who reported use of an SSRI (fluoxetine, citalopram, paroxetine, sertraline, fluvoxamine, escitalopram) or SNRI (venlafaxine, duloxetine) during the first trimester of pregnancy (n = 24 308), and another group with no reported antidepressant use (n = 1 696 966).

Source: MedPage Today

Children Must be Psychologically Assessed Before Mother’s Surrogacy, Court Rules

pregnant woman holding her belly
Source: Anna Hecker on Unsplash

The existing children of a woman who agrees to a surrogate pregnancy must be psychologically assessed before an agreement can be sanctioned. This is according to a recent ruling by Judge Brenda Neukircher at the High Court in Pretoria.

In her ruling, Judge Neukircher laid down further guidelines to be followed in surrogacy agreements which come before courts for approval. Some of the guidelines are in terms of the Constitutionally-entrenched principle of the “best interest of the child”.

Judge Neukircher ruled that, “Were it to be found that the surrogacy may have a harmful effect on their psychological well-being, this would be a factor that a court would be able to weigh up in the consideration of whether the agreement should be confirmed or not.”

Setting out the history of surrogacy laws in South Africa, Neukircher said that one provision was that a surrogate mother must have a documented history of at least one pregnancy, a “viable delivery”, and a living child of her own.

Neukircher noted the importance for the courts to consider the impact a surrogate pregnancy would have on the woman’s existing child or children. “How does a surrogate pregnancy affect the surrogate mother’s own child/children? Bearing in mind that they watch her pregnancy for nine months, know she is carrying a child and see her going to hospital to deliver a baby and then comes home without a baby in her arms. Is it important that the interest of these children be protected and, if so, how does a court do that?” she stated.

The applicants in the matter before Neukircher were financially stable. They already had a ten-month-old baby born through a previous surrogate arrangement with the same surrogate mother. The surrogate mother had previously been a surrogate for other couples and had once given birth to twins.

Neukircher said the couple had one frozen egg left and now wanted another child with the surrogate mother. “In all respects, they function as a stable family unit and I’m satisfied that they are able to care for a second child financially, emotionally, physically and educationally. Any child that will be born of this surrogacy will have his/her best interests catered to in every aspect of the (Children’s Act),” the Judge said.

Turning to the surrogate mother, Judge Neukircher said she was married and had two children of her own aged ten and seven years old. “At the time of the first surrogacy, they were six and three. Each time their mother carries a child as a surrogate, they are confronted by her pregnancy which does not end in a child being brought home to join their family. My concern was how healthy, psychologically, it is for children to go through this process?”

Neukircher said she had ordered that expert reports be compiled on the surrogate’s physical suitability to have another child, and the effect, if any, of her surrogate pregnancies on her own children.

She said the report revealed that both the surrogate’s children did not want her to have more children of her own. “Both were proud of the fact that she was helping others have a family and it seems both have adjusted to the fact that she acts as a surrogate….they do not see [the babies] as being part of their own family….they do not want their mother to bring baby home”.

She said the “invaluable report” highlighted the importance that the children of surrogate mothers needed to be prepared for the pregnancy “which goes a long way to alleviating any possible anxiety”.

The Judge said lawyers for both the commissioning parents and the surrogate mother and her husband had agreed that in not requiring such expert reports, the legislature had overlooked the “best interests” principle when it came to existing children. She said the Act laid down compliance factors for surrogacy agreements, including that a court must consider the personal circumstances and family situation of all concerned.

Going forward, Neukircher said, this must include an assessment of children already born. In this matter, she granted an order confirming the agreement.

Written by Tania Broughton for GroundUp.

Source: GroundUp

Caesarean and Induced Deliveries Fell During Pandemic

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During the first few months of the COVID pandemic, premature births from caesarean and induced deliveries fell by 6.5% – and remained consistently lower throughout, according to research reported in the journal Pediatrics. This is likely a result of fewer prenatal visits due to lockdown and social distancing rules, the researchers suggested, and call into question how many such interventions are necessary.   

The study, the first to examine pandemic-era birth data at scale, raises questions about medical interventions in pregnancy and whether some decisions by doctors may result in unnecessary preterm deliveries, according to Assistant Professor Daniel Dench, the paper’s lead author.

“While much more research needs to be done, including understanding how these changes affected fetal deaths and how doctors triaged patient care by risk category during the pandemic, these are significant findings that should spark discussion in the medical community,” A/Prof Dench said.

In effect, the study begins to answer a question that never could have been resolved in a traditional experiment: What would happen to the rate of premature C-sections and induced deliveries if women didn’t see doctors as often, especially in person, during pregnancy?

Doing such a study would be unethical, but lockdown had a side effect of reducing prenatal care visits by more than a third, according to one analysis. That gave A/Prof Dench and colleagues an opportunity to evaluate the impacts, after all.

The researchers took records of nearly 39 million US births from 2010 to 2020, and compared them to expected premature births (born before 37 weeks) from March to December 2020. 

The researchers found that in March 2020, when lockdowns began in the US, preterm births from C-sections or induced deliveries immediately fell from the forecasted number by 0.4%. From March 2020 to December 2020, the number remained on average 0.35% below the predicted values. That translates to 350 fewer preterm C-sections and induced deliveries per 100 000 live births, or 10 000 fewer overall.

Before the pandemic, the number of preterm C-sections and induced deliveries had been rising. Spontaneous preterm births also fell by a small percentage in the first months of the pandemic, but much less than births involving those two factors. The number of full-term caesarean and induced deliveries increased.

“If you look at 1000 births in a single hospital, or even at 30 000 births across a hospital system, you wouldn’t be able to see the drop as clearly,” said A/Prof Dench. “The drop we detected is a huge change, but you might miss it in a small sample.”  

The researchers also corrected for seasonality, for example, preterm births are higher on average in February than in March, which helped them get a clearer picture of the data.

The research comes with caveats. Up to half of all preterm C-sections and induced deliveries are due to a ruptured membrane, which is a spontaneous cause. But in the data Dench and his team used, it’s impossible to distinguish these C-sections from the ones caused by doctors’ interventions. So, Dench and co-authors are seeking more detailed data to get a clearer picture of preterm deliveries.

Still, these findings are significant because the causes for preterm births are not always known.

“However, we know for certain that doctors’ interventions cause preterm delivery, and for good reason most of the time,” A/Prof Dench said. “So, when I saw the change in preterm births, I thought, if anything changed preterm delivery, it probably had to be some change in how doctors were treating patients.”

The researchers’ findings raise a critical question: Was the pre-pandemic level of doctor intervention necessary?

“It’s really about, how does this affect foetal health?” said A/Prof Dench. “Did doctors miss some false positives – did they just not deliver the babies that would have survived anyway? Or did they miss some babies that would die in the womb without intervention?”  

A/Prof Dench plans to use foetal death records from March 2020 to December 2020 to answer this question. If he finds no change in foetal deaths at the same time as the drop in preterm births, that could point to “false positives” in doctor intervention that can be avoided in the future. Learning which pregnancies required care during the pandemic and which ones didn’t could help doctors avoid unnecessary interventions in the future.  

“This is just the start of what I think will be an important line of research,” A/Prof Dench said.

Source: Georgia Institute of Technology

Scientists Discover the Neurological Basis of Food Cravings in Pregnancy

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By examining mice, which get pregnancy cravings similar to humans, scientists have identified the neurological basis of food craving during pregnancy.

During pregnancy, the mother’s body undergoes a series of physiological and behavioural changes to create an environment facilitating the embryo’s development. Frequent consumption of tasty, high calorie foods driven by the cravings contributes to weight gain and obesity in pregnancy, with possible negative consequences for the baby’s health.

“There are many myths and popular beliefs regarding these cravings, although the neuronal mechanisms that cause them are not widely known,” noted study leader March Claret, at the University of Barcelona and leader of the study published in the journal Nature Metabolism.

The researchers found that the brains of pregnant female mice undergoes changes in the functional connections of the brain reward circuits, as well as the taste and sensorimotor centres. Mice, like pregnant women, are also more sensitive to sweet food, and develop binge-eating behaviours towards high calorie foods. “The alteration of these structures made us explore the mesolimbic pathway, one of the signal transmission pathways of dopaminergic neurons. Dopamine is a key neurotransmitter in motivational behaviours,” notes Claret, member of the Department of Medicine of the UB and the Diabetes and Associated Metabolic Diseases Networking Biomedical Research Centre (CIBERDEM).

The team saw that dopamine levels and dopamine receptor (D2R) activity increased in the nucleus accumbens, a brain region involved in the reward circuit. “This finding suggests that the pregnancy induces a full reorganisation of the mesolimbic neural circuits through the D2R neurons,” noted study leader Roberta Haddad-Tóvolli. “These neuronal cells – and their alteration – would be responsible for the cravings, since food anxiety, typical during pregnancy, disappeared after blocking their activity.”

The team demonstrated that persistent cravings have consequences for the offspring, affecting the metabolism and development of neural circuits that regulate food intake, leading to weight gain, anxiety and eating disorders. “These results are shocking, since many of the studies are focused on the analysis of how the mother’s permanent habits – such as obesity, malnutrition, or chronic stress – affect the health of the baby. However, this study indicates that short but recurrent behaviours, such as cravings, are enough to increase the psychological and metabolic vulnerability of the offspring,” concluded Claret.

The conclusions of the study could contribute to the improvement of nutritional guidelines for pregnant women in order to ensure a proper prenatal nutrition and prevent the development of diseases.

Source: University of Barcelona

IVF Babies Have Better Quality of Life as Adults

Pregnant with ultrasound image
Source: Pixabay

Being conceived via assisted reproductive technology (ART), such as IVF, could boost quality of life in adulthood, according to the results of a new study published in Human Fertility. The findings offer reassuring news for people who have been conceived with ART, and those who need to use the technology to conceive.

“Our findings suggest that being ART-conceived can provide some advantages on quality of life in adulthood, independent of other psychosocial factors,” said lead author Karin Hammarberg of Monash University. “Together with previous evidence that adults conceived by ART have similar physical health to those who were naturally conceived, this is reassuring for people who were conceived with ART—and those who need ART to conceive.”

In the more than four decades since the first birth following in vitro fertilization (IVF) in 1978, more than 8 million children have been born as a result of ART. In that time, many studies have evaluated the physical health, development and psychosocial well-being of ART-conceived children compared with those naturally conceived (NC). But currently, there is less known about the health and quality of life of adults who were conceived by ART.

The study recruited 193 young adults conceived through ART and 86 through NC. These participants completed questionnaires, which included a standardised quality of life measure (World Health Organization Quality of Life – Brief Assessment [WHOQoL-BREF]), when aged 18–28 years (T1) and again when aged 22–35 years (T2). The WHOQoL-BREF assesses four domains of quality of life: 1) physical 2) psychosocial 3) social relationships and 4) environment.

The researchers looked at the associations between factors present at T1 (mode of conception, the mother’s age when the participant was born, sexual orientation, family financial situation in secondary school, perceptions of own weight, number of close friends, frequency of vigorous exercise and quality of relationships with parents) and the scores on the four domains of WHOQoL-BREF at T2.

After making statistical adjustments to account for other psychosocial factors present in young adulthood, the results showed that being ART-conceived was strongly linked with higher scores (better quality of life) on both the social relationships and environment WHOQoL-BREF domains at T2. In addition, having less psychological distress, a more positive relationship with parents, a better financial situation, and perceptions of being about the right weight at T1 were associated with higher scores on one or more WHOQoL-BREF domains at T2.

“Children conceived via ART are nowadays a substantial part of the population—and it’s important to continue to evaluate the long-term effects of ART on their physical health and well-being as they progress through adolescence into adulthood,” said Hammarberg. “When accounting for other factors present in young adulthood, being ART-conceived appears to confer some advantages in quality of life. Perhaps unsurprisingly, we also found that, independently of how the person was conceived, having a better relationship with parents, less psychological distress, and a better family financial situation in young adulthood contributed to a better adult quality of life.”

This is the first study to explore the contributions of being conceived with ART and psychosocial factors present in young adulthood to the quality of life of adults. While the findings are reassuring, they should be interpreted with caution because many of those who took part in the first study did not take part in the follow-up study.

Source: Taylor & Francis

COVID Vaccination During Pregnancy Does not Cause Complications

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COVID vaccination during pregnancy is not associated with a higher risk of pregnancy complications, according to a large scale Swedish and Norwegian study published in the journal JAMA.

The study, which comprised almost 160 000 pregnancies, found there to be no increase in the risk of preterm birth, growth retardation, low Apgar scores at birth or the need for neonatal care after vaccination against COVID during pregnancy.

“The results are reassuring and can hopefully make pregnant individuals more willing to get vaccinated,” said co-first author Anne Örtqvist Rosin, researcher at the Department of Medicine, Karolinska Institutet.

Studies have shown that, compared to non-pregnant peers, pregnant women are at risk of serious COVID requiring intensive care with a higher risk of death. Preterm births are also more likely in pregnant women with severe COVID. COVID vaccines have been available in Sweden and Norway since January 2021, and in May 2021 Sweden recommended all pregnant individuals to have a COVID jab, followed in August by Norway.

“We’re still seeing that vaccination rates are lower than in the rest of the population, so it’s likely that there’s some concern about how the vaccines affect the pregnant individual and the foetus,” explained Dr Örtqvist Rosin. “When the vaccines were produced, pregnant women were not included in the large clinical studies, and until now there have been no population-based data about any risk there might be to them.”

The researchers linked Sweden’s Pregnancy Register and Norway’s Medical Birth Register to each country’s vaccination register to obtain data on if and when pregnant individuals were vaccinated and with which vaccine. The study included a total of 157 521 individuals who gave birth between January 2021 and January 2022, of whom 18% had been vaccinated. It was found that vaccinated individuals were at no higher risk than unvaccinated of developing one of the studied complications.

The majority of the pregnant individuals included in the study were vaccinated after week 12 in accordance with current recommendations, and 95% received an mRNA vaccine. This should be factored in when interpreting the results, which were similar for the different mRNA vaccines regardless of whether one or two doses were given. Vaccination during the third trimester and vaccination with the Moderna vaccine was associated with a slightly lower risk of needing neonatal care.

A possible benefit of vaccination during pregnancy is that the antibodies generated pass through the placenta, conferring a certain degree of protection against COVID to the newborn baby.

“We’re now planning to study how long this protection lasts, and if SARS-CoV-2 infection or vaccination during pregnancy has any other lasting effects on the child’s health,” said joint last author Professor Olof Stephansson at the Karolinska Institutet .

Source: Karolinska Institutet

WHO Warns of Lethal Tranexamic Acid Mix-ups in Intrathecal Administration

Intravenous IV drip in woman's hand
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The World Health Organization is alerting health care professionals about the risk of lethal administration errors that can potentially occur with tranexamic acid (TXA) injection. There have been reports of TXA being mistaken for obstetric spinal anaesthesia used for caesarean deliveries resulting in inadvertent intrathecal administration.

Intrathecal TXA is a potent neurotoxin and neurological sequelae are manifested, with refractory seizures and 50% mortality. The profound toxicity of intrathecal TXA was described in 1980. In a 2019 review, Patel et al. identified 21 reported cases of inadvertent intrathecal injection of TXA since 1988, of which 20 were life-threatening and 10 fatal. It appears that mortality risk is greater after caesarean delivery. Sixteen were reported between 2009 and 2018.

WHO recommends early use of intravenous TXA within three hours of birth in addition to standard care for women with clinically diagnosed postpartum haemorrhage (PPH) following vaginal births or caesarean section. TXA should be administered at a fixed dose of 1g in 10 ml (100 mg/ml) IV at 1 ml per minute, with a second dose of 1g IV if bleeding continues after 30 minutes. In South Africa, the incidence of maternal bleeding after caesarean delivery has been characterised as a national emergency, and obstetric haemorrhage remains the third most common cause of maternal mortality at 17%.

However, problems can arise as TXA is frequently stored in close proximity with other medicines, including injectable local anaesthetics indicated for spinal analgesia (eg, for caesarean section). The presentation of some of the local anaesthetics is similar to the TXA presentation (transparent ampoule containing transparent solution), which can be administered in error instead of the intended intrathecal anaesthetic, and resulting in serious undesirable adverse effects.

Obstetricians from several countries have recently reported inadvertent intrathecal TXA administration and related serious neurological injuries. In a South African clinical alert, Bishop et al. highlighted the different appearances of TXA used in state and private hospitals, with one example in private hospitals appearing very similar (white label, red text) at first glance to spinal bupivacaine and stored in the same container. Applicable recommendations were provided by the authors.

TXA is a lifesaving medicine, however, this potential clinical risk should be considered and addressed by all operating theatre staff. Reviewing of existing operating theatre drug handling practice is required in order to decrease this risk, such as storage of TXA away from the anaesthetic drug trolley, preferably outside the theatre.

Source: World Health Organization

Severe COVID Raises Risk of Pregnancy Complications

Source: Pixabay

A University of Oxford study of over 4000 pregnant women indicates that severe COVID in pregnancy increases the risk of pre-labour caesarean birth, a very or extreme preterm birth, stillborn birth, and the need for admission to a neonatal unit.  

The study, published in Acta Obstetricia et Gynecologica Scandinavica, included 4436 pregnant women hospitalised in the UK with symptomatic COVID from March 1, 2020 to October 31, 2021, of whom 13.9% of had severe COVID. As well as having increased risks of adverse pregnancy-related outcomes, women with severe infection were more likely to be aged 30 years or over, be overweight or obese, be of mixed ethnicity, or have gestational diabetes compared with those with mild or moderate infection.  

“This new analysis shows that certain pregnant women admitted to a hospital with COVID face an elevated risk of severe disease. However, it shows once again the strongly protective effect of vaccination against severe disease and adverse outcomes for both mother and baby,” said senior author Marian Knight, FMedSci, of the University of Oxford. “This study emphasises the importance of ensuring that interventions to promote vaccine uptake are particularly focused towards those at highest risk.”

Source: Wiley

Endocrine-disrupting Chemicals Present in Many Pregnancies

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Researchers in Europe have shown that up to 54% of pregnant women in Sweden were exposed to complex mixtures of endocrine-disrupting chemicals disruptive to brain development.

While current risk assessment tackles chemicals and their allowable exposures on an individual basis, these findings show the need to take mixtures into account for future risk assessment approaches. The study was published in Science.

A growing body of evidence has shown that industrially produced chemicals have endocrine disrupting properties and can thus be dangerous to human and animal health and development. A huge number of new compounds is released every year into the environment during the production of plastic derivatives and other goods.

While exposures for individual chemicals falls below thresholds, exposure to the same chemicals in complex mixtures can still impact human health. However, all current exposure thresholds, are based on chemicals being examined individually. Therefore, an alternative strategy needed to be tested, in which the actual mixtures measured in real life exposures could be tested as such in both the epidemiological and experimental setting. The EDC-MixRisk project set out to tackle this unmet need.

“The uniqueness of this comprehensive project is that we have linked population data with experimental studies, and then used this information to develop new methods for risk assessment of chemical mixtures,” said Carl-Gustaf Bornehag, professor at Karlstad University, Project Manager of the SELMA study.

The study was conducted in three steps:

  1. A mixture of chemicals in the blood and urine of pregnant women was identified in the Swedish pregnancy cohort SELMA, associated with delayed language development in children at 30 months. This critical mixture included a number of phthalates, bisphenol A, and perfluorinated chemicals.
  2. Experimental studies uncovered the molecular targets through which human-relevant levels of this mixture disrupted the regulation of endocrine circuits and of genes involved in autism and intellectual disability.
  3. The findings from the experimental studies were used to develop new principles for risk assessment of this mixture.

“It is striking that the findings in the experimental systems well reflected what we found in the epidemiological part, and that the effects could be demonstrated at normal exposure levels for humans,” said Joëlle Rüegg, professor of environmental toxicology at Uppsala University.

“Human brain organoids (advanced in vitro cultures that reproduce salient aspects of human brain development) afforded, for the first time, the opportunity to directly probe the molecular effects of this mixture on human brain tissue at stages matching those measured during pregnancy. Alongside other experimental systems and computational methods, we found that the mixture disrupts the regulation of genes linked to autism (one of whose hallmarks is language impairment), hinders the differentiation of neurons and alters thyroid hormone function in neural tissue,” said Giuseppe Testa, principal investigator of the EDC-MixRisk responsible for the human experimental modelling.

“One of the key hormonal pathways affected was thyroid hormone. Optimal levels of maternal thyroid hormone are needed in early pregnancy for brain growth and development, so it’s not surprising that there is an association with language delay as a function of prenatal exposure,” said Barbara Demeneix, professor of physiology and endocrinology at the Natural History Museum in Paris.

By combining these techniques, the researchers were able to show that 54% of children included in the SELMA study were at risk of delayed language development (at age 30 months) as they were prenatally exposed to a mixture of chemicals at levels that were above the levels predicted to impact neurodevelopment. Yet this risk fell below the exposure limits for individual chemicals.

Source: EURION Cluster