Few studies appear to have investigated the prevalence of constipation for all three trimesters of the gestative period, or indeed after birth. Using a prospective 4- to 7-day weighed food diary, International Physical Activity Questionnaire and 7-day bowel habit diary, dietary factors, physical activity levels and bowel habit parameters were assessed and examined concurrently at weeks 13, 25, 35 of pregnancy and 6 weeks post-partum. Ninety-four primiparous pregnant women were initially recruited, and 72, 59, 62 and 55 completed the first, second, third trimester and post-partum study stages, respectively. Key dietary factors and physical activity levels were compared between the constipated and non-constipated groups from each of the three trimesters and after parturition. Compared with non-constipated mothers-to-be, constipated participants consumed statistically significantly less water in the first trimester (P = 0.04), more food in the second trimester (P = 0.04), and less iron (P = 0.02) and food (P = 0.04) in the third trimester and after birth, respectively. No statistically significant differences were identified between light, moderate and vigorous physical activity levels when groups were compared. This study demonstrates that dietary factors may play a role in terms of preventing, or alleviating, bowel habit perturbations both throughout and after pregnancy. Further research is required to investigate the interrelationship between physical activity and constipation during and after pregnancy.