Ultrasound during pregnancy are done to:

Confirm the pregnancy and its location: Sometimes the embryos can develop in the fallopian tube instead of the uterus. It helps to detect tubal pregnancy.

• To determine your baby's gestational age:
• To confirm the number of babies.
• To evaluate the baby's growth.
• To study the details of the placenta
• To identify the possible fetal abnormalities.
• Screening for Down syndrome.
• To investigate the bleeding and other symptoms.
• To perform prenatal tests like amniocentesis. Chorionic villus sampling.

Different types of ultrasound:

• Standard ultrasound: It is two-dimensional images to determine gestational age and evaluate baby's growth and development.
• Advanced ultrasound.
• Trans vaginal ultrasound.
• Tree-dimensional (3-D) ultrasound.
• Doppler imaging.
• Fetal electrocardiography.

When are ultrasounds done?

• Fetal ultrasound can be done at any point during pregnancy.
• If there is suspicion of ectopic pregnancy or other problems, you need a transvaginal ultrasound soon after you find out you're pregnant. A doppler ultrasound may detect the baby's heartbeat as early as six weeks.
• Routine fetal ultrasounds are typically done between 18 to 20 weeks. If baby's health needs to be monitored closely, ultrasounds may be repeated throughout the pregnancy.

Ultrasound in first trimester is done:

• To detect the viability of the pregnancy.
• To rule out tubal or ectopic pregnancy.
• To look for twins or multiple pregnancies.
• To look for abnormalities in the baby and in the uterus.

Ultrasound scan in the second trimester is done (weeks 12-28 )

• To measure the baby's growth.
• To determine the baby's position.
• To measure amniotic fluid.
• To identify abnormalities.
• To determine the position of the placenta.