Examination not sensitive enough to detect breech babies

Aug 3 2006

The routine examination doctors use to check if a baby is lying in the correct position before birth is not sensitive enough, concludes a study published on bmj.com today.

The authors suggest that there is room for improvement by all pregnancy care providers.

The position of a baby in the womb in late pregnancy is important because if it is not lying in the normal head-down position (known as cephalic presentation) vaginal delivery may be difficult or impossible. Diagnosis of non-cephalic presentation after the onset of labour is associated with increased complications and death.

Fetal presentation is usually assessed by palpating the abdomen, but little is known about the accuracy of this in late pregnancy. So researchers in Australia decided to examine the diagnostic accuracy of this procedure.

They identified 1633 women with a single pregnancy at 35-37 weeks’ gestation attending an antenatal clinic at an obstetric hospital in Sydney. Each woman underwent clinical examination to assess the position of their baby. This was followed by an ultrasound scan to confirm the diagnosis.

Clinical examination detected 70% of non-cephalic presentations. Correct diagnosis was greater for women with a previous pregnancy and lower body mass index.

If this figure was applied to a general maternity population of 1000 women, clinical examination would identify 101 women as having a non-cephalic presentation but in only 56 would this be correct; 24 women with non-cephalic presentation would be missed altogether, say the authors.

Introduction of routine ultrasonography to assess fetal presentation in late pregnancy would improve diagnostic accuracy, but costs, resource availability, and feasibility need to be considered, as well as the potential deskilling of care providers in performing clinical examination, they write. However, lower rates of accuracy found among overweight or obese women suggest that ultrasonography in late pregnancy for these women is required.

Clinical examination to assess fetal presentation is a relatively simple procedure and, with ongoing diligence and regular audit and feedback, accuracy may be increased. Variability in accuracy rates by examiner and level of experience also suggest there is room for improvement by all pregnancy care providers, they conclude.