This leaflet is to help you understand the ultrasound determination of fetal lie and presentation.

What is fetal lie?

Fetal lie refers to the orientation of the fetus in the womb in relation to the mother and uterus. A vertical orientation (with the baby's spine aligned parallel to the mother's spine, known as a longitudinal lie) is typical, although occasionally, the position may be horizontal (transverse) or at an incline (oblique).

What is the most frequent fetal lie?

The most frequent fetal lie is the longitudinal lie, accounting for 99% of pregnancies after 28 weeks’ gestation.

How is fetal lie evaluated?

Traditionally, your obstetric caregiver using standardized manual palpation techniques, commonly known as Leopold’s maneuvers, evaluates the fetal lie. However, these maneuvers are not consistently precise. Conversely, ultrasound scanning offers an objective and reliable approach to determining fetal lie, now widely regarded as the gold standard.

What is fetal presentation?

The fetal presentation describes the fetal part that is lowest in the maternal abdomen. In case of labor, it is the lowest fetal part in the birth canal. Many fetal presentations are possible:

  • Cephalic presentation: the fetal head is the lowest fetal part. This is by far the most common presentation at term of pregnancy and in labor.
  • Breech: the fetal buttock or feet are the lowest fetal part.
  • Shoulder: the fetal shoulder is the lowest fetal part.
  • Compound: a combination of more than one fetal structure lies closest to the pelvic inlet.

How can the fetal presentation be evaluated?

Traditionally, fetal presentation is assessed using clinical examination. This can include maternal abdominal palpation and vaginal examination. The latter is particularly useful in labor, when cervical dilatation allows the examiner to directly feel the lowermost fetal part.

In case of uncertainty, mainly when the fetal lowermost part is difficult to appreciate by abdominal or vaginal examination, fetal presentation can be easily evaluated by transabdominal ultrasound.


Last updated April 2024

Ultrasound determination of fetal lie and presentation