News
Study uncovers protective function of morning sickness
Morning sickness symptoms such as nausea and food aversions are linked to healthy inflammatory responses that help protect both mother and fetus during pregnancy, new research shows.
Up to 80 per cent of early-stage pregnant women experience nausea, vomiting and aversions to certain foods or smells.
Researchers say these symptoms point to a delicate immune balance rather than health problems.
The responses appear to be part of the body’s mechanism for tolerating the half-foreign fetus while avoiding potentially harmful substances.
UCLA researchers studied blood samples from 58 Latina women in Southern California, measuring cytokines — proteins that regulate immune responses — while tracking morning sickness symptoms through questionnaires.
Sixty-four per cent reported odour or food aversions, mainly to tobacco smoke and meat. Sixty-seven per cent experienced nausea and 66 per cent vomiting.
Women with aversions to tobacco smoke showed a stronger shift toward inflammatory responses. Nausea, vomiting and food aversions were also tied to more pro-inflammatory immune activity.
Molly Fox, UCLA anthropology professor and corresponding author, explained the challenge for the immune system in pregnancy.
She said: “During pregnancy, a mother’s immune system faces a tricky challenge: it has to protect both her and the fetus from infection, but without accidentally attacking the fetus, whose genetic identity is half-foreign because it is half derived from the father.
“Normally, the immune system attacks anything that seems foreign, so in pregnancy, it has to carefully adjust to keep the fetus safe while still defending against infection.”
The researchers believe this immune balance protects mother and fetus while behavioural responses — such as avoiding certain foods — add another safeguard, especially in the first and second trimesters.
Daniel Fessler, UCLA anthropology professor and co-author, stressed the protective role of these symptoms.
He said: “Nausea, vomiting or aversions to foods or smells are not indications that something is going wrong for the mother or the fetus.
“It’s likely an indication that everything is moving along normally, and a reflection of the body’s healthy and helpful immune response.”
Fox noted that human pregnancies face unique challenges.
In many mammals, the fetal compartment has barriers separating it from the mother’s blood supply, where her immune cells are.
But in humans, we have a unique setup — fetal cells are bathed in maternal blood. Humans have the most invasive of all placentas, burrowing deep into maternal tissue.
So humans need unique strategies to prevent the mother’s immune system from attacking the fetus.”
Fessler added that these responses may be evolutionary adaptations.
The researcher said: “Nowadays, you will see labels on packages of ground beef or soft cheese that warn pregnant women to be cautious about these products because of the risks of foodborne illness during pregnancy.
“Aversions to certain odours and foods, and nausea and even vomiting, appear to be evolution’s way of achieving that same objective.”
The team said their findings could help reinforce the idea that nausea and vomiting are normal pregnancy symptoms with biological roots, potentially supporting calls for workplace adjustments and reducing stigma.
Hormone therapy started in peri- or early post-menopause was linked to a 22 per cent lower risk of cardiovascular events in women with vasomotor symptoms in a recent study.
The findings came from an observational analysis of 20 years of health data and do not show that hormone therapy caused the reduction in cardiovascular risk.
The association was strongest among Black women and women who started treatment within 10 years of menopause onset, although researchers cautioned that the findings should not guide clinical practice.
The study is the first of its kind in the US to assess the risk of future cardiovascular events among women with vasomotor symptoms who use hormone therapy during peri- and early postmenopause.
Samar R. El Khoudary, professor and chair of the Department of Epidemiology at the VCU School of Public Health and one of the study’s senior researchers, said: “The menopause transition represents a critical window for understanding how hormone therapy may relate to cardiovascular disease risk. Our findings suggest that timing of initiation may influence cardiovascular outcomes.”
The researchers stressed that the findings do not support using hormone therapy to prevent cardiovascular disease.
Potential benefits must also be weighed against risks, including the increased breast cancer risk observed with longer-term use.
The study was not a randomised controlled trial, the gold-standard method for testing biomedical treatments.
Rebecca C. Thurston, associate dean for Women’s Health Research at the University of Pittsburgh School of Medicine and one of the study’s senior researchers, said: “These findings point to women with vasomotor symptoms as those who may show cardiovascular benefit from hormone therapy initiated during the perimenopause and postmenopausal years.
“However, conclusions should be tempered by the observational nature of the study, and findings should not guide clinical practice.”
Vasomotor symptoms, meaning hot flushes and night sweats, affect up to 80 per cent of women during the menopause transition and last for an average of seven to ten years.
Their frequency and severity build through perimenopause and typically peak in early postmenopause.
Hormone therapy replaces oestrogen and progesterone that women’s bodies stop producing after menopause and is currently the most effective treatment for these symptoms.
Clinical trials led by the Women’s Health Initiative in the early 2000s raised concerns about hormone therapy’s impact on heart disease, stroke, breast cancer and other risks, leading to years of reluctance among patients and providers to use the treatment.
El Khoudary said: “Hot flashes and night sweats have a significant impact on a woman’s quality of life and ability to work productively.
“While hormone therapy is an effective treatment for these symptoms, questions have remained about its cardiovascular effects, particularly the importance of when treatment is initiated during the menopause transition.”
More recent research suggests the effects of hormone therapy on the heart and vascular system may vary by age and treatment timing, with women younger than 60 who start treatment closer to menopause onset having different levels of risk.
In 2026, the US Food and Drug Administration removed “black box” warnings from hormone therapy products, reflecting evolving evidence on the benefits and risks of treatment.
Researchers from Virginia Commonwealth University and the University of Pittsburgh analysed data from more than 2,700 women taking part in the Study of Women’s Health Across the Nation (SWAN).
The women reported vasomotor symptoms and had not previously experienced cardiovascular events.
Clinical data collected between 1997 and 2017 were used to examine whether women who started hormone therapy for vasomotor symptoms were more or less likely to experience stroke, congestive heart failure, heart attack or revascularisation procedures than women who did not start treatment.
El Khoudary said: “By using data from the SWAN study, we essentially were able to emulate a series of hypothetical clinical trials to gain a deeper understanding into how hormone therapy taken to mitigate vasomotor symptoms during peri- and early postmenopause influences cardiovascular risk over time.
“It allowed us to examine clinically meaningful cardiovascular disease events over long-term follow-up in a population and treatment window that has been challenging to study prospectively.”
Starting hormone therapy during peri- or early postmenopause was associated with an estimated 22 per cent lower risk of cardiovascular disease events.
Women who began hormone therapy within 10 years of menopause onset had an estimated 27 per cent lower risk compared with women who did not start treatment.
Among Black women, starting therapy during peri- or early postmenopause was associated with an estimated 49 per cent lower risk of cardiovascular disease events.
No clear reduction was seen among women who started therapy more than 10 years after menopause onset or among White women and other racial and ethnic groups.
El Khoudary said: “The differences in cardiovascular outcomes by race and ethnicity are notable, particularly because Black women are more likely to experience severe vasomotor symptoms.
“These findings highlight the need to better understand how hormone therapy timing may influence cardiovascular outcomes across diverse populations.”
It remains unclear why cardiovascular risk differed according to when hormone therapy was started, although researchers believe differences in blood vessel health with age may play a role.
Small bowel microbiome differences between women and men may help explain why some conditions are more common in women, a study suggests.
The small bowel microbiome is the community of microorganisms living in this part of the digestive tract, where they play vital roles in immune function, metabolism and hormonal regulation.
Researchers found differences between women and men in the composition and organisation of these microbial communities. One bacterial community containing Granulicatella was found only in women.
The study was conducted by investigators at Cedars-Sinai Health Sciences University.
Ruchi Mathur, director of clinical research and clinical operations for the Medically Associated Science and Technology (MAST) Program at Cedars-Sinai and corresponding author of the study, said: “One intriguing finding was a bacterial community containing Granulicatella, which we found only in women.
“Bacteria in this community appear at increased levels in women with polyendocrine metabolic ovarian syndrome, formerly known as polycystic ovary syndrome.”
The researchers also identified differences between women and men in how microbes in the small bowel produce fructans, complex carbohydrates known to trigger digestive symptoms in irritable bowel syndrome (IBS).
IBS is far more common in women than men.
Mathur, who is also a professor of medicine, said: “Our findings show that biological sex is a critical variable in the small bowel microbiome.
“We must consider it as we move toward more personalised approaches to understanding and treating disease.”
An experimental cancer drug reduced bone loss and body fat in mice modelling post-menopausal changes, early research suggests.
The compound, CADD522, appeared to strengthen bones and help the animals stay leaner after surgery designed to mimic hormonal changes seen after menopause.
The treatment remains at an early experimental stage and has so far only been tested in animals.
The study, led by the University of East Anglia, investigated CADD522, which was originally developed to block a protein involved in the growth and spread of several cancers.
Mice treated with the compound for eight weeks showed significant improvements in bone health. Scans found increased bone volume and better preservation of the honeycomb-like structures inside bones that are crucial for strength and resilience.
Blood tests suggested the treatment stimulated new bone growth without interfering with the body’s normal process of breaking down and rebuilding bone.
Dr Darrell Green, lead researcher from UEA’s Norwich Medical School, said: “Osteoporosis affects around one in three women over the age of 50, leaving sufferers vulnerable to painful fractures that can seriously impact quality of life.
“Current treatments exist, but many are plagued by side effects, safety concerns or inconvenient dosing schedules that make long-term use difficult.”
The researchers also found that mice receiving CADD522 weighed less than untreated mice despite eating the same amount of food.
They had less body fat and fewer fat deposits in their bone marrow, a process commonly seen after menopause and linked to declining bone health.
The team also examined brain tissue and found that the drug appeared to reverse several menopause-related changes in fatty acids.
Levels of omega-3 fats including DHA remained largely intact, while several other lipid abnormalities shifted back towards healthier patterns.
Green said: “We didn’t directly test for memory or thinking ability, but our work raises questions about whether this drug could one day help address wider menopause-related health problems.”
Safety experiments in mice, rats and dogs found that CADD522 could be taken orally and was well tolerated.
The compound also appeared to be metabolised more slowly in human tissue than in rodents, potentially improving its performance in people.
“This is still in the early stages and has so far only been tested in animals but we hope that the benefits will translate to humans to ultimately reduce fracture rates,” added Green.
The research was led by UEA in collaboration with the University of Maryland, the Scintillon Research Institute in San Diego and the University of Stirling.
Safety testing was funded by The Sir William Coxen Trust as part of the development of CADD522 as a childhood cancer treatment.
Diagnosis2 weeks agoMajor UK study could be a ‘game-changer’ for heavy periods and endometriosis
Entrepreneur1 week agoKOVE Medical raises €1.7 million to improve safety of foetal surgery
Fertility2 weeks agoOne week left to apply: W Accelerate with Merck KGaA and M Ventures
Pregnancy1 week agoUK study aims to transform maternity care for high-risk pregnancies
Mental health2 weeks agoPMDD after SSRIs or hormones: Why the brain may be the missing treatment target
Diagnosis2 weeks agoArk Surgical secures further institutional backing to accelerate US expansion
Menopause5 days agoMenopause hormone treatment may ease brain fog, study suggests
Motherhood2 weeks agoThousands of UK women develop undiagnosed PTSD after childbirth each year – study