Category: Obstetrics & Gynaecology

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Rate of Twin Births At A Global High

On By ModernMedia
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The first comprehensive global survey of twinning has reported an enormous increase in the number of twin births around the world, but appears to be plateauing.

One main reason for the increase is that, due to IVF and other fertility services being more readily available, the number of non-identical twin births is increasing. This is due to practices such as hormone stimulation releasing multiple ova, as well as the now discouraged practice of releasing multiple embryos into the womb in IVF. A systematic review also found that with IVF, letting embryos mature before implantation is also linked to increased odds of monozygotic twins. as well as women becoming pregnant later in life – age increases the likelihood of having natural, non-identical twins, peaking at age 35 to 39.

However, instead of continuing to climb, there are signs that twin births have reached a maximum.

“The trends are really quite striking,” said Christiaan Monden, a professor of sociology and demography at Oxford University. “Over the past 40 to 50 years we’ve seen a strong increase in twinning rates in rich, developed countries, and that has led to more twins in both a relative and an absolute sense than we’ve seen ever before.”

The researchers analysed twinning rates from 2010 to 2015 in 165 countries, which covered 99% of the world’s population. In 112 of those countries, they examined further birth records for 1980 to 1985. 

Although Africa is still the leading continent for twin births, other regions are catching up. The researchers found that, since the 1980s, twinning rates have risen from 9 to 12 per 1000 births, with the greatest rise in more developed regions such as  America (71%), Europe (60%) and Asia (32%).

In the UK, twinning rates rose about 62% but are thought to have fallen since the launch of a campaign to reduce multiple births in 2007. 

Raj Mathur, the chair of the British Fertility Society and a consultant gynaecologist at St Mary’s Hospital, said: “It doesn’t surprise us that twinning rates have increased because the availability of assisted reproduction has increased and also because women are slightly older when they have their first children, and both those things will increase the twin rate.[…]

“I think we’ve reached a peak in terms of twinning rates from medical interventions, certainly in the developed world, but the spread of IVF in Africa and South America is still rather limited on a per capita basis, and there are vast numbers of sub-fertile people in Africa particularly who don’t have access to IVF.

Dr Mathur added a note of caution about IVF, as twins have more risks such as lower birth weights and higher still birth and infant mortality rates

“The challenge will be how to spread IVF to them without also giving them higher twin rates. The majority of twin babies are absolutely fine, but there is no doubt that a twin pregnancy carries greater risks for the mother and the baby, so when we can avoid it we should avoid it. The principle we follow is neatly summed up by the phrase ‘one at a time’,” Mathur said.

Source: The Guardian

Categories : Obstetrics & GynaecologyTags :

New Study Finds Marijuana THC Persists in Breast Milk

On By ModernMedia


A new study has found that tetrahydrocannabinol (THC) from marijuana can linger in breast milk for up to six weeks after ceasing marijuana use.

Marijuana is the most commonly used dependent substance in pregnancy, with up to half of users continuing through pregnancy. The use of marijuana through pregnancy is likely due to its perceived safety as well as   THC readily crosses the placental barrier, and cannabinoid receptors have been identified in both the placenta and the foetus. However, most studies done on marijuana and pregnancy dates from the 1980s –  this study is the first of its kind to examine the levels of THC in breast milk since one in 1982.

“With the increasing utilisation of marijuana in society as a whole, we are seeing more mothers who use marijuana during pregnancy,” said primary investigator Erica Wymore, MD, MPH, Neonatologist, Children’s Colorado and Assistant Professor of Pediatrics, University of Colorado School of Medicine. “However, given the lack of scientific data regarding how long THC persists in breast milk, it was challenging to provide mothers with a definitive answer regarding the safety of using marijuana while breastfeeding and simply ‘pumping and dumping’ until THC was no longer detectable in their milk. With this study, we aimed to better understand this question by determining the amount and duration of THC excretion in breast milk among women with known prenatal marijuana use.”

The researchers screened women at the Children’s Colorado and UC Health’s University of Colorado Hospital for reported marijuana use or detected THC, who were willing to abstain from marijuana for the six week duration of the study. Of the 394 women screened, 25 enrolled in the study. Seven of these women were able to abstain from their marijuana use, while the others were not able to due depending on it for stress, sleep, and pain relief.

“This study provided invaluable insight into the length of time it takes a woman to metabolise the THC in her body after birth, but it also helped us understand why mothers use marijuana in the first place,” said Maya Bunik, MD, MPH, senior investigator, medical director of the Child Health Clinic and the Breastfeeding Management Clinic at Children’s Colorado and professor of pediatrics at the CU School of Medicine. “To limit the unknown THC effects on foetal brain development and promote safe breastfeeding, it is critical to emphasise marijuana abstention both early in pregnancy and postpartum. To help encourage successful abstention, we need to look at – and improve – the system of supports we offer new moms.”

While the study was not about the impact of maternal marijuana use on childhood development, longitudinal studies dating from the 1980s show that for children born to mothers who smoked marijuana during pregnancy, there are long-term issues with cognitive and executive functioning, including impulsivity, as well as deficits in learning, sustained attention and visual problem-solving skills. One recent retrospective study has also linked marijuana use in pregnancy to autism in children. Dr Wymore points out that this is cause for concern as currently available marijuana has a potency five to six times greater than what was available prior to legalisation.

Source: News-Medical.Net

Journal information: Wymore, E.M., et al. (2021) Persistence of Δ-9-Tetrahydrocannabinol in Human Breast Milk. JAMA Pediatrics. doi.org/10.1001/jamapediatrics.2020.6098.

Categories : Neurology Obstetrics & GynaecologyTags :

Brain ‘Rewired’ by Sound Early in the Womb

On By ModernMedia

Playing music to foetuses in the womb to enhance their brain development is a popular practice even if thus far not grounded in science, but new research has shown that there may be some effect even at very early stages.

New research from John Hopkins University indicates that ‘wiring changes’ made in response to sounds occur even earlier than thought before. The ear canals of newborn mice only open after 11 days, while in humans, the ear canals open at 20 weeks’ gestation. The researchers used the mice as a model for human foetuses, and examined their neural connections at one week old.

“As scientists, we are looking for answers to basic questions about how we become who we are,” said Patrick Kanold, PhD, professor of biomedical engineering at The Johns Hopkins University and School of Medicine. “Specifically, I am looking at how our sensory environment shapes us and how early in foetal development this starts happening.”

Prof Kanold started out in electrical engineering before switching to neuroscience. His field of research is on the cortex, the outer layer of neurons underneath which lies the white matter which consists of connective neurons.

In developing foetuses, in the white matter, subplate neurons can be found at 12 weeks in human gestation and the second embryonic week in mice. This subplate neurons are the precursors to neurons and die off over a period lasting from before birth to several months old. Before they disappear, they make a connection between the thalamus, which is an important sensory gateway, and the middle layers of the cortex.

“The thalamus is the intermediary of information from the eyes, ears and skin into the cortex,” explained Prof Kanold. “When things go wrong in the thalamus or its connections with the cortex, neurodevelopmental problems occur.”

The subplate neurons respond to sound before the cortical neurons, prompting two questions for Prof Kanold: When sound signals reach the subplate neurons, does anything happen, and can a change in sound signals reflect changes in the brain circuits at these young ages?

To answer these questions, the researchers used mice genetically engineered to be deaf, unable to convert sound into nerve signals. In deaf, week-old mice, there were 25-30% more connections between subplate and cortical neurons.

“When neurons are deprived of input, such as sound, the neurons reach out to find other neurons, possibly to compensate for the lack of sound,” said Prof Kanold. “This is happening a week earlier than we thought it would, and tells us that the lack of sound likely reorganises connections in the immature cortex.”

To compare the difference extra auditory stimuli made, the researchers put 2-day old pups in a quiet enclosure or an enclosure with a constant beeping sound. There were differences between the subplate neuron connections for beeping and quiet enclosure mice, but not as great as between the deaf and hearing mice. The quiet enclosure mice had stronger connections between the subplate and cortical neurons, similar to the deaf mice. The mice in the beeping enclosure also had a greater diversity in neural circuitry.

“In these mice we see that the difference in early sound experience leaves a trace in the brain, and this exposure to sound may be important for neurodevelopment,” explained Prof Kanold.

The researchers are planning to examine how sound in early development impacts the brain in later life, as well as how sounds in the womb influences neural wiring. This has application for cochlear implants for children born deaf. They also plan to study premature infants neural wiring problems and develop biomarkers for abnormal subplate neuron development. 

Source: Medical Xpress

Journal information: Early peripheral activity alters nascent subplate circuits in the auditory cortex, Science Advances (2021). DOI: 10.1126/sciadv.abc9155

Categories : Obstetrics & GynaecologyTags :

Onset of Morning Sickness Narrowed Down

On By ModernMedia

The onset of “morning sickness”, the nausea and vomiting that often occurs near the beginning of pregnancy and normally resolves at 12-14 weeks, has been narrowed down in a new study from researchers at the University of Warwick.

The cause of nausea and vomiting of pregnancy (NVP) had historically been ascribed to psychological conditions, but currently is believed to have a multifactorial basis, involving various genetic, endocrine and gastrointestinal factors.

The study involved 256 women who became pregnant, keeping a diary recording the onset of nausea and vomiting, their last menstruation and date of ovulation as measured by a urine test.Determining the date of the start of pregnancy as determined by the date of their last ovulation, the first onset of NVP was 8 to 10 days, compared to 20 to 30 days as measured from the date of their last menstruation.

Lead author Prof Roger Gadsby, Warwick Medical School, said: “The precise course of pregnancy sickness is unknown, but this research shows that it occurs at a specific developmental stage, in a specific timeslot. For researchers it narrows our focus in terms of where we look for the cause. If we know that symptoms occur in a very narrow window 8-10 days after ovulation, researchers can concentrate their efforts on that particular stage of development to find the cause of the condition, both anatomically and biochemically.”

Knowing that the onset of NVP has such a tight timeframe will help future research narrow down a biological cause behind it, and help generate targets for treatment development.

An unexpected outcome of the study was a very high prevalence of NVP of 94%, compared to the 80% calculated in prior research. This is explained by the fact that data were regularly collected from participants from before they became pregnant to 60 days after their last menstruation, as opposed to most studies asking women to recall symptoms after they became pregnant.

Prof Gadsby added, “What we’ve shown is that more people get symptoms of pregnancy sickness than has ever been shown before, and one of the reasons for that is that this research has picked up mild early symptoms that tend to fade by 7-8 weeks. In other studies those symptoms would have faded by the time the research started.”

Source: News-Medical.Net