Is there an effect of prenatal breech position on locomotion at 2.5 years?

Abstract

The long-term effects of intra-uterine breech position on postnatal development of motor functions have not been systematically investigated. The aim of the present study was to investigate the possible effect of prenatal breech position on locomotion. Two complementary studies were conducted. Firstly, a gait analysis was carried out. Secondly, in a functional task the children were challenged to cross a gap until their maximum attainable crossing distance was reached. The mean age of the twenty-one children who participated in this study was 32.1 months (SD = 4).

Children who lied in prenatal breech position (n = 10) had a walking pattern comparable to the control group (n = 11). There were no differences in step length, step width, foot rotation, foot rotation asymmetry, hip flexion, hip extension and range of motion of the hip. Thus, prenatal breech position, although a long-term effect was found, does not seem to have functional consequences on locomotion.

However, the total amount of extra hip motion during the gap crossing was significantly smaller in children who lied in breech position compared to the control group. This was due to significant less extra hip flexion at the side of the leading leg. Nevertheless, comparable maximum gaps were crossed in both groups. Apparently, these children had a different solution of the challenging task of gap crossing. They compensated the lack of extra hip flexion by applying more extra hip extension.

Introduction

Breech presentation is defined as an intra-uterine fetal position in which the fetal head is at the top of the uterus and the fetal tail bone is at the bottom of the uterus. At 30–32 weeks of pregnancy about 10–15% of all fetus are in breech presentation. At a term delivery (between 37–42 weeks of pregnancy) the majority of fetuses assume the vertex position, with the fetal head being the lowermost part of the fetus, situated at the bottom of the uterus. Only 3% of fetuses remain in breech at term. There is a well-established relationship between breech presentation and dysplasia of the hip [24], [26] resulting in hip joint instability [6], [14] and hip dislocation of the new-born baby [17]. These problems are not due to the mode of delivery [13] as has been previously suggested [8], [25], but appear to be the consequences of intra-uterine position. Intra-uterine breech position in conjunction with weeks of gestational age at birth was shown to be the only factor that significantly predisposes for hip joint instability [21]. This relationship between weeks of gestation and hip joint instability due to prenatal breech position [7], [14] can be explained by the fact that during the final weeks of pregnancy the fetus is growing in size and the amount of amniotic fluid decreases, resulting in a confined intra-uterine environment restricting hip extension during rest and activity. Because the lower segment of the uterus is smaller than the corporal part of the uterus, and surrounded by bony structures, the pelvis and the hips of a fetus in breech position are much more enclosed than those of a fetus in vertex position. This environment [22] has mechanical consequences, which can lead to dislocation and even deformation of the hips [16]. For example, it was shown that fetuses in breech position have a 10° greater anteflexion of the femoral neck than fetuses in vertex position [15].

Sival et al. [28] were the first to look into the effect of intra-uterine breech position on postnatal motor functioning in healthy infants. They reported a significant limitation of passive hip extension for all infants born in breech position in the first 12 weeks after birth. They also found that, up to 12 weeks, breech infants kept their hips significantly longer in flexion compared to infants born in vertex position. Although the age at which developmental milestones, for example walking, were reached was not different between both groups, observation of the posture at 12–18 months, while walking unsupported showed that seven out of twelve infants who were in breech showed an abnormal walking pattern with a small flexion in the hips resulting in a slight forward bending of the trunk. Based on these findings Sival et al. suggest a long-term effect of prenatal breech position on functional hip dynamics during locomotion. However, Sival et al. based their conclusions on inspection of video recordings. Bartlett et al. [9] reported minor transient differences in breech-presenting infants compared with cephalic-presenting infants. The breech infants showed more open popliteal angles at birth and they had significantly lower motor scores at 6 weeks than the normative sample. Bartlett et al. reported that these differences were transient, but in view of the findings of Sival et al., we were interested in a possible long-term effect on functional tasks of the lower limbs.

The aim of the present study was to investigate further the possible role of prenatal breech position, and thus prenatal environmental constraints, on qualitative aspects of locomotion. Two complementary studies were conducted in children ranging in age from 25–38 months. Firstly, a gait analysis based on footprint patterns and gait kinematics around the hip joint, measured by goniometers, was carried out. Gait analysis based on footprint patterns is a common method to determine walking parameters in toddlers [1], [2], [3], [10], [19], [20], [23], [27]. Secondly, in a functional task the children were challenged to cross a gap that was widening with every successive trial until their maximum attainable crossing distance was reached. This second study was especially carried out because possible differences in flexion and extension capabilities between children who lied in breech position and children who lied in vertex position during pregnancy might show up in a functional task, which requires a large range of motion of the hip joint, rather than in a conventional gait study.