In a University of Nottingham study, it has been found that the restricted growth of an embryo is in positive correlation with the chances of a spontaneous abortion; more commonly known as a miscarriage. Scientists found that 78% of single-baby pregnancies which ended in a miscarriage involved the smallest embryos.
The researchers took under account 500 cases of single and twin embryos, measuring them during the first trimester via an ultrasound scan (the crown-rump length was measured). Following this, each pregnancy was monitored until the children were born. Based on their measurements, the researchers were able to prove the hypothesis that poor growth of an embryo within the first trimester (or first 12 weeks) of a pregnancy was a good predictor for miscarriage.
This research was presented at the British Fertility Society annual meeting in Leeds.
In addition to calculating that 77.8% of single-baby pregnancies that ended in a miscarriage were due to restricted growth of embryos, researchers further supported this theory by stating that 98.1% of single embryo pregnancies did not miscarry when embryo growth went unrestricted.
Dr Shyamaly Sur, who was in charge of this study, said embryo growth should allow doctors to predict the risk of miscarriage. The BBC quoted Dr Sur saying, “There are various reasons why some embryos show restricted growth in the early stages of pregnancy. It could be down to an abnormality in the foetus or something in the environment of the womb.” Furthermore, a consulting gynaecologist, Dr Raj Mathur, stated; “We also need to look at blood supply to the embryo and whatever genes are passed on from the father too,” (The BBC quoted Raj Mathur) suggesting that more research needs to be done on why embryo growth can be restricted. He also stated that the mother’s health history should be taken under consideration.
In twin-pregnancies, the study showed a slightly different reading. Only 28.6% of twin pregnancies that miscarried were because of restricted embryo growth. However, 98% of twin pregnancies that did not miscarry were not growth restricted. The study also found that twin embryos grew at the same rate as single embryos during the first trimester.
“More research is now needed to investigate the relationship between growth and the underlying causes of miscarriage,” said Dr Sur. Additionally, he added, twin pregnancies seem to be slightly different in terms of miscarriage (as suggested by their study readings). “It could be that twins grow normally and then miscarry.”
Hopefully in the near future, after further research, scientists will be able to use the information they have gathered to save embryos from the risk of miscarriage.