This is the first ultrasound in the pregnant female. It is usually performed after 1 to 2 weeks of missed periods.
This is done to:

• See the uterus and the adjoining structures and to rule any uterine structural malformations which may hamper the pregnancy
• For confirmation of intrauterine pregnancy. Sometimes the developing baby (i.e the embryo at this stage) can be implanted outside the uterine cavity when it is known as ectopic pregnancy which if diagnosed early can be managed medically without any surgical intervention. An early ultrasound examination helps in reducing the morbidity caused because of ectopic pregnancies.
• For ascertainment of fetal viability
• For assessing the chorionicity and amnionicity in multiple pregnancies. In twins or higher order pregnancies it is essential to know the type of twinning as it can have an important impact on the outcome of the pregnancy and guide the doctor in the management of the pregnancy. The best time to assess the same is at early pregnancy scan at around 7-8 weeks