There are many signs and indications that a mother's pregnancy started with twins (or more) but one of the twins (or all but one of a multiple pregnancy) died, either during the pregnancy or around birth. Research has revealed that for every pair of twins born with both alive, there are at least ten pregnancies where one twin dies. As twins make up about 1% of the population, that means that 1 in every 10 people is a womb twin survivor.
This slideshow will tell you most of what you need to know:
Medical
Signs of twin pregnancy
The mother’s pregnancy
Mother abnormally large around the waist in the first three months
First trimester bleeding
Complete miscarriage but pregnancy continued
Suspected miscarriage but pregnancy continued
Attempted abortion but pregnancy continued
Doctor or nurse suspected twin pregnancy
Another person suspected twins
Mother experienced blunt trauma in an accident or assault when pregnant
Mother experienced infection during pregnancy
Mother experienced severe trauma during pregnancy
Mother experienced starvation through illness, famine or hyperemesis
Mother took hyper-ovulation drug (eg. Clomid)
More that one embryo transplanted after IVF
Ultrasound evidence of second sac
Features of labour and delivery
Birth was traumatic
Breech birth
Small for dates
Placenta unusually large
Within body of survivor
Dermoid cyst
Teratoma
Foetus in fetu
Sexual organs of opposite sex
Secondary sexual characteristics of opposite sex
Cerebral palsy in the survivor
Birth defects in survivor
Split organs
Congenital abnormality