Tag: premature delivery

Categories : Obstetrics & GynaecologyTags :

Blood Type Linked to Risk of Premature Birth, New Study Suggests

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A new study, led by clinical researchers from Imperial’s Department of Metabolism, Digestion and Reproduction and Imperial College Healthcare NHS Trust, has uncovered a link between a pregnant woman’s blood group and her risk of spontaneous premature birth, which the team hopes could in future lead to more personalised approaches to preventing early labour.

“The treatments we currently offer to prevent preterm birth have barely changed in decades. This research opens the door to more targeted, biologically-informed interventions.”

Dr Lynne Sykes Clinical Associate Professor, Department of Metabolism, Digestion and Reproduction

The findings, published in npj Biofilms and Microbiomes, draw on more than 74 000 anonymised maternity records from Imperial College Healthcare NHS Trust and data from high-risk pregnancies. The team found that women with blood groups B and O were associated with a higher risk of spontaneous preterm birth, while those from blood group A were associated with a lower risk. 

The clinical researchers believe this is because women with blood group A are more likely to carry higher proportions of a protective bacterium and show less inflammation, both associated with healthy pregnancies.

The research also found that the blood group associations vary depending on underlying risk factors, including previous cervical surgery or a history of late miscarriage or premature birth. In women whose only risk factor was previous cervical surgery, blood group B was associated with a higher likelihood of preterm delivery. In contrast, in women with a history of late miscarriage or prior premature birth, blood group O was associated with the highest risk.

The team used advanced microbiome analysis on a subset of 596 high-risk women to investigate possible biological mechanisms at work. They found that women with blood group A were more likely to carry higher proportions of Lactobacillus crispatus, a ‘good’ bacterium associated with healthy pregnancies. In contrast, women of blood group B and O were more likely to harbour a more diverse bacterial signature. In women with blood group O, a direct link was observed between this bacterial signature, inflammation, and spontaneous preterm birth.

Speaking about the findings, Dr Lynne Sykes, lead researcher and Clinical Associate Professor at Imperial College London, and Consultant Obstetrician at Imperial College Healthcare NHS Trust, said: “Although we did not establish causation, we have identified a genetic link that can influence the risk of spontaneous premature birth in women. This could potentially impact women in the future by identifying risk earlier in pregnancy and by offering more tailored interventions. While we need further research, the prospect of moving towards personalised care in this area is hugely exciting.” 

Next steps

The team demonstrated that blood group sugars are secreted into the vaginal fluid and that binding of these sugars can occur to key good and bad bacteria found in the vagina. However, one important limitation of the study was that researchers did not have “secretor status” data for participants, a genetic factor that affects whether blood group sugars are secreted in vaginal fluid. 80% of the population are “secretors”, whereas 20% do not secrete blood group sugars, so future studies that incorporate this information may strengthen the findings.

The research suggests that the ABO blood group, routinely tested early in pregnancy, could be used to help stratify preterm birth risk, especially when considered alongside other clinical factors. Importantly, the team accounted for ethnicity, known to affect both blood group prevalence and preterm birth risk, ensuring these results were not driven by population differences.

Dr Sykes added: “What excites me most is the opportunity this presents for truly personalised medicine in pregnancy, something that has been sorely lacking in our field. The treatments we currently offer to prevent preterm birth have barely changed in decades. This research opens the door to more targeted, biologically-informed interventions.”

The study also lays the groundwork for new therapeutic approaches. A clinical trial beginning this autumn, funded by March of Dimes in the US, will explore whether probiotic treatment with Lactobacillus crispatus (Lactin-V) can help reduce premature birth in high-risk women – and whether response to the treatment may vary by blood group.

Source: Imperial College London

Categories : Environmental Effects Obstetrics & GynaecologyTags :

Excess Heat Linked to Preterm Delivery in Study of over a Million Births

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As global temperatures continue to rise, a new study of 1.2 million births in Sydney over two decades has shown a strong association between the risk of pre-term birth and exposure to extreme hot temperatures in the third trimester of pregnancy. The data suggested that this association with extreme temperature might be reduced by greenery.

The findings suggest health services should consider preparing for an increase in preterm births as our climate warms.

The Monash University-led study, published in JAMA Pediatrics, looked at the relationship between preterm birth, exposure to high temperatures as well as the mitigating factor of exposure to trees and overall greenness. Excess heat was defined as trimester temperatures higher than the 95th percentile of trimester distributions over the 20-year period.

The study, led by A/Prof Shanshan (Shandy) Li from the Monash School of Public Health and Preventive Medicine, looked at 1.2 million births – including 63 144 preterm births – occurring in Sydney, between 2000 and 2020, using the New South Wales Midwives Data Collection.

The research team cross-referenced this data with historical temperature data, as well as tree cover and overall greenness levels derived from satellite images.

The research concluded that exposure to both daytime and night-time extreme heat in the third trimester was strongly associated with increased preterm birth risks, unlike the same exposure in either the first or second trimesters.

This association existed for all levels of area-level greenness, although the strength of the association was slightly diminished for women living in areas with more trees and other greenery, raising the intriguing possibility that greenness might ameliorate some of the excess risk from extreme heat exposure in the third trimester that deserves further study.

First author A/Prof Li is an expert in environmental impacts on children’s health.

She says, “The presence of greenery, especially trees, has the potential to mitigate heat levels and lower the risks of preterm birth associated with heat. Greenery also has positive physical and mental health impacts beyond just pregnancy and birth outcomes. We should be integrating heat mitigation strategies such as increasing green spaces into urban planning, to improve public health.”

According to Professor Yuming Guo, senior author on the study, and also from Monash University, there has been increasing but still limited epidemiological evidence linking prenatal environmental temperatures with birth outcomes.

“Emerging evidence suggests that night-time air temperature, particularly extreme night-time heat, significantly impacts health, including sleep and rest. Sleep quality and duration affects various aspects of health, and disturbances in these factors may have consequences for pregnancy outcomes,” he said.

“High night-time temperatures can disrupt circadian rhythms and potentially influence blood pressure, which may be an issue for pregnant individuals. Given the projected increase in extreme temperatures as our planet warms, understanding its impacts on birth outcomes and developing strategies to mitigate the risks becomes crucial.”

Source: Monash University

Categories : Lab Tests and Imaging Obstetrics & GynaecologyTags :

New Ultrasound Method can Predict Risk of Preterm Delivery

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Researchers have developed a way to use ultrasound to estimate the risk of delivering a baby preterm. The new method measures microstructural changes in a woman’s cervix using quantitative ultrasound. The method works as early as 23 weeks into a pregnancy, according to the research, which is published in the American Journal of Obstetrics & Gynecology Maternal Fetal Medicine.

The current method for assessing a woman’s risk of preterm birth is based solely on whether she has previously given birth prematurely. This means there has been no way to assess risk in a first-time pregnancy.

“Today, clinicians wait for signs and symptoms of a preterm birth,” such as a ruptured membrane, explained lead author Barbara McFarlin, a professor emeritus of nursing at University of Illinois Chicago.

“Our technique would be helpful in making decisions based on the tissue and not just on symptoms.”

The new method is the result of more than 20 years of collaboration between researchers in nursing and engineering at UIC and University of Illinois Urbana-Champaign. In a study of 429 women who gave birth without induction at the University of Illinois Hospital, the new method was effective at predicting the risk of preterm births during first-time pregnancies.

And for women who were having a subsequent pregnancy, combing the data from quantitative ultrasound with the woman’s delivery history was more effective at assessing risk than just using her history.

The new approach differs from a traditional ultrasound where a picture is produced from the data received.

In quantitative ultrasound, a traditional ultrasound is performed but the radio frequency data itself is read and analysed to determine tissue characteristics.

The study is the culmination of a research partnership that began in 2001 when McFarlin was a nursing PhD student at UIC. Having previously worked as a nurse midwife and sonographer, she had noticed that there were differences in the appearance of the cervix in women who went on to deliver preterm.

She was interested in quantifying this and discovered that “no one was looking at it.”

She was put in touch with Bill O’Brien, a UIUC professor of electrical and computer engineering, who was studying ways to use quantitative ultrasound data in health research.

Together, over the past 22 years, they established that quantitative ultrasound could detect changes in the cervix and, as McFarlin had suspected long ago, that those changes help predict the risk of preterm delivery.

The preterm birth rate hovers around 10-15% of pregnancies, O’Brien said.

“That’s a very, very high percentage to not know what is happening,” he said.

If a clinician could know at 23 weeks that there was a risk of preterm birth, they would likely conduct extra appointments to keep an eye on the foetus, the researchers said.

But since there had previously been no routine way to assess preterm birth risk this early, there have been no studies to show what sort of interventions would be helpful in delaying labour.

This study, O’Brien explains, will allow other researchers to “start studying processes by which you might be able to prevent or delay preterm birth.”

Source: University of Illinois Chicago