Maternally perceived fetal movement patterns: The influence of body mass index

Maternal reports of decreased fetal movements are associated with adverse pregnancy outcome, but there are conflicting data about perception of fetal movements in women with obesity.

To compare perceived fetal movements in women with obesity (body mass index [BMI] ≥30 kg/m²) and women with normal BMI (<25 kg/m²).

Data from two separate pregnancy studies were used for this analysis; the Healthy Mums and Babies (HUMBA) trial, which recruited women with obesity and the Multicentre Stillbirth Study (MCSS), which recruited women from a general obstetric population. Fetal movement data were collected using identical interviewer-administered questionnaire in each study. We compared fetal movement strength, frequency and pattern between HUMBA and MCSS women with obesity and MCSS women with normal BMI.

Participants were 233 women with obesity and 149 with normal BMI. Mean (SD) gestation at interview was similar between groups (36.9 [2.2] vs 36.6 [0.9], P = 0.06). Perceived fetal movement strength and frequency did not differ between groups. In both women with obesity and normal BMI, a diurnal fetal movement pattern was present, with the majority reporting strong or moderate movements in the evening (88.7% vs 99.3%) and at night-time (92.1% vs 93.1%). Women with obesity, were more likely to report strong fetal movements when hungry (29.1% vs 17.7%, P = 0.001) and quiet fetal movements after eating (47.4% vs 32.0%, P = 0.001).

In women with obesity compared to normal BMI, strength and frequency of fetal movements were similar, although patterns were altered in relation to maternal meals.