Even twins are more likely to suffer birth defects, such as blindness and cerebral palsy, and are less likely to survive than single births. To reduce the risks, doctors try to get mothers to have the babies one at a time, but this is not possible in all cases. In some multiple pregnancies, doctors may recommend that some of the embryos be aborted so that the others have more chance of survival because they have more space to develop. But there is a high chance of major problems. Drugs The most common fertility treatment is drugs which produce extra eggs.
Most women produce only one egg per monthly cycle.
Doctors can increase this number to more than 20, but most prefer to put a limit of two or three because of the risks of multiple births. The eggs are fertilised in a test tube and doctors normally return the embryos to the womb and wait to see if they develop. Many doctors are worried that they are being put under increasing pressure to use more of the fertility drugs to produce more eggs and so increase the chance of the woman getting pregnant. US research shows people undergoing fertility treatment would prefer to have multiple births than have no children. This is despite reports that those who have multiple births are more likely to suffer depression, anxiety and emotional problems and more prone to divorce.