18 weeks pregnant but ultrasound unable to detect baby?

It is unlikely that an ultrasound would not be able to detect a baby at 18 weeks of pregnancy, as the baby is typically large enough to be seen by this stage. However, there are some cases where an ultrasound may not be able to detect a baby, such as:

- Early pregnancy. If you are earlier in your pregnancy than you think you are, the baby may not be visible on an ultrasound yet.

- Implantation issues. If the fertilized egg implants in an unusual location, such as the fallopian tube, it may not be visible on an ultrasound.

- Ectopic pregnancy. An ectopic pregnancy occurs when the fertilized egg implants outside of the uterus, such as in the fallopian tube. This can be dangerous and requires medical attention.

- Fetal demise. If the baby has died, it may not be visible on an ultrasound.

If you are concerned that your ultrasound did not detect a baby, it is important to talk to your doctor. They can determine if you are pregnant and, if so, whether there are any problems with the pregnancy.