Question

why vomiting is considered as first sign of preganancy? And how does it occur?

Answer 1

The exact cause of the sickness is not known. It is probably due to the hormonal changes of pregnancy. Feelings of sickness (nausea) and vomiting tend to be worse in twin and other multiple pregnancies. There are a number of risk factors that may make you more likely to experience nausea and vomiting in pregnancy.