pregnancy

Around 15% of recognized pregnancies end in miscarriage, and it is estimated that almost half of all conceptions are lost in early stages, without people even realizing it. Now, a team from the United States and Denmark has analyzed data from more than 139,000 embryos from in vitro fertilization of nearly 23,000 couples and has found several genetic variants associated with a higher risk of miscarriage. Many of these are associated with meiosis, a key cell division process in sex cells. The authors, whose study is published in Nature, acknowledge that the new data will not allow for a precise estimation of individual risk, because the most important factors remain age and environmental elements.

There is no link between the use of paracetamol during pregnancy and an increased risk of autism, attention deficit hyperactivity disorder (ADHD) or intellectual disability among children, according to a meta-analysis published in The Lancet Obstetrics, Gynaecology, & Women’s Health. 

The BMJ has published a meta-analysis about weight gain in pregnant women and the risks it poses to their health and that of their babies. According to the study, 68% of pregnancies involve weight gain that is either above or below the recommended level, which is associated with complications such as premature birth, high birth weight, and admission to intensive care. The review included data from 1.6 million women from various regions of the world and different income levels, recorded between 2009 and 2024.

A team has analysed estimated data on exposure to pollution during and after pregnancy and its possible link to a diagnosis of autism in more than two million births in Canada between 2002 and 2022. Their findings are that greater exposure to small PM_2.5 particles containing sulphate or ammonium is associated with a higher likelihood of receiving a diagnosis of autism in the first five years of life. A slightly increased proportion was also observed with greater exposure to ozone during certain weeks of pregnancy and in the first year of life. The results are published in the journal JAMA Network Open.

On Monday, US federal health authorities will advise pregnant women against taking paracetamol in the early stages of pregnancy, unless they have a fever, as reported yesterday by The Washington Post. The announcement will be accompanied by a recommendation for a drug called leucovorin as a treatment for autism, the article adds. Donald Trump said yesterday: ‘Tomorrow we are going to have one of the most important announcements... from a medical standpoint, I think, in the history of our country. I think we have found an answer to autism.’

A Canadian team analysed samples from women undergoing in vitro fertilisation and found that higher concentrations of THC metabolites—the main psychoactive substance in cannabis—were associated with a higher rate of oocyte maturation and a lower number of embryos with the correct number of chromosomes. The latter could be replicated at similar concentrations under laboratory conditions. The authors, who published their findings in the journal Nature Communications, acknowledge that the study does not have sufficient statistical power to draw conclusions, but it does warn of possible risks to women's fertility.

The miscarriage rate is higher in women who have had a computed tomography scan before pregnancy than in those who have not been exposed before conception, according to a study published in the Annals of Internal Medicine. The research includes data on more than five million pregnant women in Canada between 1992 and 2023. According to the study, the miscarriage rate increases with the number of scans: from 117 miscarriages per 1,000 pregnancies in women who have had a single test, to 142 in those who have had three or more – compared with 101 miscarriages per 1,000 pregnancies in women who have not had a previous scan.

Prenatal exposure to triptans—alone or in combination with other migraine medications—does not increase the risk of developmental disorders in children up to age 14, according to research published in Neurology. The study is based on data from more than 26,000 pregnancies in a national registry in Norway and includes autism spectrum disorders, language disorders, and attention deficit hyperactivity disorder, among other diagnoses.

In humans, larger birth canals are associated with slower labour and less back pain, but a higher risk of osteoarthritis of the hip, while narrower birth canals are associated with a lower risk of pelvic floor disorders, but a higher risk of obstructed labour, according to one study. The analysis published in Science is based on genetic and clinical data and bone densitometry images from more than 31,000 people in the UK Biobank to identify 180 genetic positions associated with seven ‘highly heritable’ pelvic characteristics.

A review of 202 studies involving more than 56 million mother-child pairs has observed an association between maternal diabetes — including pre-pregnancy and gestational diabetes — and an increased risk of neurodevelopmental disorders in children, such as autism spectrum disorders, attention deficit hyperactivity disorder or intellectual disability. The authors, who publish the results in the journal The Lancet Diabetes & Endocrinology, call for a cautious interpretation of the association, as there is currently little evidence of a causal relationship.