Influence of pregnancy related anthropometric changes on plantar pressure distribution during gait-A follow-up study.

BACKGROUND: As foot constitutes the base of support for the whole body, the pregnancy-related anthropometric changes can result in adaptive plantar pressure alterations. The present study aimed to investigate how pregnancy affects foot loading pattern in gait, and if it is related to body adjustments to growing foetus that occur in the course of pregnancy. METHODS: A prospective longitudinal study included 30 women. Three experimental sessions in accordance with the same procedure were carried out in the first, second and third trimesters of pregnancy. First, the anthropometric measures of the body mass and waist circumference were taken. Then walking trials at a self-selected speed along a ~6-m walkway were registered with the FreeMED force platform (Sensor Medica, Italy). Vertical foot pressure was recorded by the force plate located in the middle of the walkway. FINDINGS: The correlation of individual foot loading parameters across different trimesters was relatively high. Nevertheless, our results revealed a longitudinal foot arch flattening with the strongest effect in late pregnancy (P = 0.01). The anthropometric characteristics also influenced the foot loading pattern depending on the phase of pregnancy. In particular, arch flattening correlated with the body mass in all trimesters (r≥0.44, P≤0.006) while the medial-lateral loading index correlated only in the first (r = 0.45, P = 0.005) and second (r = 0.36, P = 0.03) trimesters. Waist circumference changes significantly influenced dynamic arch flattening but only in the late pregnancy (r≥0.46, P≤0.004). In the third trimester, a small though significant increase in the right foot angle was observed (P = 0.01). INTERPRETATION: The findings provided the characteristics of the relative foot areas loading throughout pregnancy. Growing abdominal size increases the risk of medial arch flattening, which can result in less stable gait. The observed increase in foot angle in late pregnancy may constitute a strategy to enhance gait stability.

Does the first trimester of pregnancy induce alterations in the walking pattern?

INTRODUCTION: From among many studies observing the walking pattern throughout pregnancy, only two items monitor the influence of pregnancy on the movement system during gait considering the period before gestation. RESEARCH QUESTION: Does the women's gait pattern at the end of the first trimester undergo changes in comparison to body movement pattern before pregnancy? METHODS: All subjects who met the inclusion criteria gave signed and informed consent before the study. Two experimental sessions were arranged according to the same protocol: (P0) before pregnancy and (P1) at the end of the first trimester of pregnancy (12th week of gestation). At first the anthropometric measures were taken. Then, walking trials at a self-selected speed along a walkway were registered with Vicon 250 (Oxford Metrics Ltd.; Oxford, UK) and FreeMED force platform (Sensor Medica, Italy). RESULTS: An analysis of anthropometric parameters in 12th pregnancy week demonstrated significant changes in mean values of waist circumference and waist to hip ratio as well as waist to height ratio indexes compared to the results before pregnancy. No significant differences were found in the basic kinematic gait parameters between experimental conditions. Significant increase of mean inter-ankle distance during double support phase occurred during the first trimester of pregnancy. Also, the ratio of the ankle separation width to the pelvic width was noticeably higher in gestation. Then, angular changes of the pelvis in coronal and transverse planes throughout gait cycle during pregnancy demonstrated significant differences compared to those measured before pregnancy. At the same time in the first trimester of pregnancy no adaptive changes in the pattern of feet loading take place. SIGNIFICANCE: Since our study is of longitudinal character, in the course of pregnancy we expect compensatory mechanisms more clearly demonstrated. Therefore, we hope to identify a strategy of the gravid body progression in space.