Older mothers and the risk of stillbirth
Dr Samantha Lean, Katie Stephens, Dr Rebecca Jones, Professor Alexander Heazell, Dr Mark Dilworth
Women who become pregnant when they are over 35 are more at risk of giving birth to babies that are too small, or stillborn. We’re not sure why older mothers are more likely to suffer stillbirth, but we think it might be to do with the placenta.
Older women often have placentas that aren’t working as well as they should. If we can understand how this might cause stillbirth, we can try and create treatments that stop stillbirths by helping women to have healthier placentas.
Tommy’s are supporting the Manchester Advanced Maternal age study (MAMAS) to try and find answers. Researchers are studying over 560 women of different ages from across the UK. We have confirmed that women over 35 are more at risk of pregnancy complications, and that this risk is even higher for women over 40.
Scientists took samples of the women’s blood and placentas, as well as collecting information about the women’s lifestyles. They found that placentas from older women showed signs that they were aging faster than those from younger women. The cells in the placenta were also under more stress: they were less able to repair damage, and showed signs of inflammation. We think that these factors might stop them working normally, meaning it is more difficult for the baby to get the oxygen and nutrients that it needs.
Meanwhile, researchers also looked at mice to see if age is related to stillbirth. Studying mice can be helpful, as it means scientists don’t have to worry about the complicated differences in lifestyles that humans have. Again, older mice had more stillbirths, and a larger number of babies that didn’t grow properly. They also had heavier placentas that were less able to transport nutrients to their growing babies.
Scientists are currently treating older pregnant mice with a substance called melatonin. This is a hormone that normally plays a part in controlling our sleeping patterns. Early findings from this are promising: so far, there have been no stillbirths in mice who were given melatonin. There are also signs that their babies are growing more, and their placentas working better.
Going forward, we will carry on looking at melatonin, along with other substances, to see if they can be used to prevent stillbirths. Results so far suggest that these could be promising ways of preventing stillbirth in older mothers.
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This study is fully funded by Tommy's and takes place in a Tommy's centre