**3. Breech presentation**

Breech presentation is defined as a fetus in a longitudinal lie with the buttocks or feet closest to the cervix and the head closest to the fundus of the uterus. There are three types of breeches.

The incidence of breech presentation in neonates before the 28th gestation-week is 20%. This percentage decreases to 3-4% with advancing gestational age. These data show that most babies turn around during the third trimester of pregnancy. Under normal circumstances, as the shape of the uterus changes, the fetus turns simultaneously to headfirst position between the 28th and the 32nd week of pregnancy. As of this moment, the uterus will expand more vertically than transversely. This situation facilitates the previous fetal position. Although the simultaneous turn is more common during the weeks of pregnancy mentioned above, this turn is also possible at delivery. However, this is more common in multiparous women rather than in primiparous women. Thus, it seems that the fetus plays an active role at adopting the best position in the uterus.

et Hannah, 2003). This analysis concluded that the elective caesarean reduces both the perinatal and neonatal morbidity and mortality at the expense of a moderate increase in

This study led to a worldwide change in medical practice. Several national recommended the caesarean delivery in term breech babies. In fact, in many American and European

In view of this opinion about avoiding the vaginal delivery in breech babies by using the caesarian delivery, there has been a growing interest in retaking the external version

Definitely, the external version has become more and more relevant as well as a controversial and a topical issue since this is a valid option against the elective caesarian. It has been shown that its use significantly reduces the vaginal delivery frequency as well as the caesarian delivery frequency in breech presentation in full term pregnancies. In spite of

This review article aims to discuss the complications in breech babies and the use of external version as an alternative (regarding the process itself, the conditions and the right moment

Articles have been searched in *Medline* and *Pubmed* database as well as in the *Cochrane Database of Systematic Reviews*. The search has been limited to those studies in human beings and articles in English or Spanish developed between 1995 and 2007. Current clinical practice guidelines (from the –American, British, Canadian and Spanish national associations of obstetricians and gynecologists on external version and breech presentation have also been reviewed. Key words: Breech, cephalic version, external version, adverse

Breech presentation is defined as a fetus in a longitudinal lie with the buttocks or feet closest to the cervix and the head closest to the fundus of the uterus. There are three types of

The incidence of breech presentation in neonates before the 28th gestation-week is 20%. This percentage decreases to 3-4% with advancing gestational age. These data show that most babies turn around during the third trimester of pregnancy. Under normal circumstances, as the shape of the uterus changes, the fetus turns simultaneously to headfirst position between the 28th and the 32nd week of pregnancy. As of this moment, the uterus will expand more vertically than transversely. This situation facilitates the previous fetal position. Although the simultaneous turn is more common during the weeks of pregnancy mentioned above, this turn is also possible at delivery. However, this is more common in multiparous women rather than in primiparous women. Thus, it seems that the fetus plays

countries, this performance has become the only one to be considered.

this fact, the external version is still not implemented in many countries.

to perform it, its contraindications, its adverse effects, etc.).

an active role at adopting the best position in the uterus.

performances in order to reduce the caesarian delivery frequency.

maternal morbidity.

**2. Material and methods** 

event "and" cephalic version.

**3. Breech presentation** 

breeches.

Fig. 1. A. Frank breech (65-70%) The baby's legs are flexed at the hip, his or her knees are extended and feet next to the head. This is the most common type in pregnancies at term. **B.** Complete breech (5%) In this case, the baby's hips and knees are flexed. The fetus positions is the same as in the vertex presentation but, in this case, the polarity is reversed. **C.** Incomplete breech (-30%) The baby has one or both knees flexed so that baby's legs (not his or her bottom) are poised to deliver first. This type is common in preterm deliveries.

From the etiologic point of view, the breech presentation could be caused by situations avoiding or hampering the spontaneous cephalic version.


The incidence of breech presentation is closely related to the gestational age. In the case of single-gestation pregnancies, the preterm delivery is probably the aspect that contributes the most to a breech presentation at delivery. Before the 28th week, the incidence is almost 10 times higher than at term, and almost 12% of preterm deliveries show breech presentation. However, 50%-80% of the cases do not show any etiologic factor responsible for the breech presentation (Sociedad Española de Ginecología y Obstetricia [SEGO], 2001).
