Scientists from the Centre for Primary Care and Public Health have analysed the twin pregnancies of more than 30,000 women to identify the ideal delivery period in an attempt to reduce rates of stillbirth.

Credit: Jenn Lewald
Credit: Jenn Lewald

In the largest review of its kind the researchers recommend that in the case of pregnancies without complications, women with dichorionic twins (twins with separate placenta) should be offered delivery after 37 weeks. They also recommend that women with monochorionic twins (twins that share the same placenta) should not be offered delivery before 36 weeks.

The study was published in the British Medical Journal.

Twin pregnancies are high risk with a thirteen-fold increase in rates of stillbirth in monochorionic twins, and a five-fold increase in dichorionic twins, compared with singleton pregnancies.

Uncomplicated twin pregnancies are often delivered early in an attempt to prevent late stillbirth but delivery before term can lead to neonatal complications associated with prematurity.

Professor Shakila Thangaratinam, of the Women’s Health Research Unit here at the Blizard Institute, said: “Until now, we did not have clear recommendations on the best time to offer delivery to mothers with twin pregnancies. We know that women with twin pregnancies have a higher risk of stillbirth compared to women with singleton pregnancies, and this risk gets higher the later they are in pregnancy. However, earlier delivery can put the babies at risk of problems associated with being born prematurely including neonatal death.”

Since 2005, the number of patient safety incidents involving multiple pregnancies, including unexpected stillbirth and neonatal death, has risen by 419 per cent in the UK, and peaked in 2013-14, resulting in payouts of over £90m.

Professor Thangaratinam added: “There is a global drive to prevent stillbirths and we know that twin pregnancies are a major risk factor for stillbirths in high income countries. We hope that this research will help to complement national and international efforts to reduce the rates of stillbirth and unexpected neonatal complications in babies from women with twin pregnancies and will be useful to national guideline and hospital policy makers.”

The research was carried out in collaboration with the Global Obstetrics Network (GONET).

More information

  • Research paper: ‘Prospective risk of stillbirth and neonatal complications in twin pregnancies: A systematic review and meta-analysis’. Fiona Cheong-See, Ewoud Schuit, David Arroyo-Manzano, Asma Khalil, Jon Barrett, KS Joseph, Elizabeth Asztalos, Karien Hack, LIesbeth Lewi, Arianne Lim, Sophie Liem, Jane E Norman, John Morrison, C Andrew Combs, Thomas J Garite, Kimberly Maurel, Vicente Serra, Alfredo Perales, Line Rode, Katharina Worda, Anwar Nassar, Mona Aboulghar, Dwight Rouse, Elizabeth Thom, Fionnuala Breathnach, Soichiro Nakayama, Francesca Maria Russo, Julian Robinson, Jodie M Dodd, Roger B Newman, Sohinee Bhattacharya, Selphee Tang, Ben Willem J Mol, Javier Zamora, Basky Thilaganathan, Shakila Thangaratinam.British Medical Journal.

Taking an oral vitamin D supplement in addition to standard asthma medication is likely to reduce severe asthma attacks, according to research led by Prof Adrian Martineau in the Centre for Primary Care and Public Health here at the Blizard Institute.

Asthma is a common chronic disease affecting about 300 million people worldwide, with symptoms including wheezing, coughing, chest tightness and shortness of breath.

Low blood levels of vitamin D have been linked to increased risk of asthma attacks in children and adults with asthma. There has been a growing interest in the potential role of vitamin D in asthma management because it might help to reduce upper respiratory infections (such as the common cold) that can lead to exacerbations of asthma.

Lead author of the Cochrane Review study, Professor Adrian Martineau from the Asthma UK Centre for Applied Research in the Blizard Institute's Centre for Primary Care and Public Health, said: “We found that taking a vitamin D supplement in addition to standard asthma treatment significantly reduced the risk of severe asthma attached, without causing side effects.”

The team of Cochrane researchers looked at seven trials involving 435 children and two studies, involving 658 adults, from a broad range of countries including Canada, India, Japan, Poland, the UK, and the US. The majority of people recruited to the studies had mild to moderate asthma, and a minority had severe asthma. Most people continued to take their usual asthma medication while participating in the studies.

Based largely on trials in adults, the researchers found that giving an oral vitamin D supplement reduced the risk of severe asthma attacks requiring hospital admission or emergency department attendance from 6 per cent to around 3 per cent. They also found that vitamin D supplementation reduced the rate of asthma attacks needing treatment with steroid tablets, but that vitamin D did not improve lung function or day-to-day asthma symptoms.

Professor Adrian Martineau added: “This is an exciting result, but some caution is warranted. First, the findings relating to severe asthma attacks come from just three trials: most of the patients enrolled in these studies were adults with mild or moderate asthma. Further vitamin D trials in children and in adults with severe asthma are needed to find out whether these patient groups will also benefit.

“Second, it is not yet clear whether vitamin D supplements can reduce risk of severe asthma attacks in all patients, or whether this effect is just seen in those who have low vitamin D levels to start with. Further analyses to investigate this questions are on-going, and results should be available in the next few months.”

More information

  • Research paper: Martineau AR, Cates CJ, Urashima M, Jensen M, Griffiths AP, Nurmatov U, Sheikh A, Griffiths CJ.Vitamin D for the management of asthma. Cochrane Database of Systematic Reviews 2016, Issue 8. Art. No.: CD011511. DOI:10.1002/14651858.CD011511.pub2

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