Giles and Ylaria, the term you’re looking for is missed abortion or missed miscarriage. It’s relatively common in early pregnancy, often an empty sac or a baby without a heartbeat is seen on the 12 week scan, although the woman has no bleeding, pain or other symptoms of miscarriage.
Usually the woman undergoes a surgical evacuation of the uterus (either a D&C or suction curettage) or a medical evacuation with misoprostol (essentially “labour” is induced with drugs).
There is a risk of infection if the problem is not treated, and as the foetus is not viable the procedure is not an abortion, either medically or legally speaking.
Nowadays someone is presumed to have a right to consent, and this can only be breached if it is demonstrated they haven’t got the capacity to refuse or consent to treatment. If one cannnot understand information, or retain information, or weigh information in order to reach a decision, one cannot give informed consent, nor can one refuse consent.
In the UK at least no adult person can give or deny consent for another person. Mentally incapacitated adult persons must have their capacity assessed for each separate medical procedure, and the courts decide based on psychiatric and medical evaluations if the person is able to consent or not.
For example, a person with Down’s syndrome may have capacity to consent or refuse a simple cannula insertion as they may understand the procedure and implications of refusal, however they may not have the capacity to refuse a blood transfusion, as they do not fully understand the risks involved.
One of my patients is severely mentally disabled, and requires a surgery to remove a tumour. Although we have explained what we wish to do and why, and she has agreed, we are waiting for her psychiatrist to evaluate her in order to see if she fully has capacity to consent before we proceed. If her psychiatrist feels she does not, the court will decide what is in her best interest.