To our knowledge, this is the first study investigating the use of probiotics in constipated pregnant women. A significant increase in defecation frequency was observed. Furthermore, the presence of sensation of incomplete evacuation, sensation of anorectal obstruction, straining during defecation, abdominal pain and reflux episodes also improved significantly with the use of this probiotic mixture. No adverse effects were reported during the study.
The improvement of all important defecation characteristics in constipated pregnant women are in accordance with the results found by Bekkali et al. in 20 children with constipation using the same mixture of probiotics. The latter study reported a significant increase in bowel movements, a decrease in fecal incontinence episodes and a decrease in abdominal pain .
Our results are also in line with a recent review on the efficacy of probiotics by Chmielewska et al. . They found that Bifidobacterium lactis DN-173 010, Lactobacillus casei Shirota and Escheria Coli Nissle 1917, used in different randomised controlled trials in constipated men and non-pregnant women, increased the defecation frequency and improved stool consistency . A recent double-blind randomised placebo controlled trial in otherwise healthy constipated adults using different strains of lactobacilli and bifidobacteria also showed an increase in bowel movements, positive effects on stool consistency and on discomfort items such as abdominal bloating and anal itching . A randomised trial in constipated elderly using a mixture of probiotics including Lactobacillus rhamnosus and Propionibacterium freudenreichii showed positive results with respect to defecation frequency as well . It should be noted that the composition of the strains of probiotics used in the described studies is different and effects might therefore be strain- or product-specific. For this reason, one should be careful comparing these studies. Studies comparing the effects of these different strains are not available.
It has been suggested that the findings in men and non-pregnant women, elderly and children are not directly applicable to constipated pregnant women, because of differences in pathophysiology. The main difference is the changed hormone levels during pregnancy (e.g. progesterone) [3, 8, 9, 11, 12]. Our study was designed as a pilot study on the use of probiotics and not to elucidate the effect of probiotics on the different pathophysiological mechanisms in constipation. So, this hypothesis remains unresolved. The fact that our results are in line with published results in non-pregnant women, suggests that at least some of the pathophysiological mechanisms are independent of pregnancy and comparable to non-pregnancy, like low fibre and low fluid intake.
Pregnant women may experience constipation for the first time during pregnancy or their existing constipation symptoms increase in severity during pregnancy . Besides discomfort of constipation symptoms, straining during defecating can damage the pudendal nerve and impair the supportive function of the pelvic floor musculature [31, 32]. Furthermore disturbed defecation can result in the development of uterovaginal prolapse . Therefore it is important to recognize the symptoms of constipation and treat these complaints in an early phase of pregnancy. In clinical practice, laxatives and fibres are frequently used. Laxatives like Lactulose and Bisacodyl have proven to be safe for mother and fetus and should therefore be considered in the treatment of constipation during pregnancy . Unfortunately, their side effects, such as abdominal pain and diarrhoea, limit their use . Besides, changing dietary habits is difficult to accomplish and laxatives are considered pharmacological treatment and are not recommended as the first step in treatment of constipated pregnant women . Polyethylene glycol (PEG)-based laxatives technically meet the criteria for the ideal treatment in constipation . However, present data are insufficient to exclude any adverse effects on the foetus . Probiotics are non-pharmacological and widely used in an otherwise healthy population. Based on the results of our study, probiotics could be of additional value in the treatment of constipation in clinical practice in pregnant women.
This study was designed as a pilot study with inherent limitations. Due to the lack of a control group, an important placebo effect of probiotics cannot be excluded. Besides that, because of the uncontrolled design, there is no information available on the natural course of constipation during pregnancy. However, since this study shows positive results on constipation symptoms, it is worthwhile to perform a large randomised trial to unravel the efficacy of this mixture probiotic strains in constipated pregnant women.
It was difficult to include the 20 patients needed for this pilot study. We experienced that underreporting of defecation problems is a major issue due to a taboo among pregnant women, midwives and doctors to discuss defecation patterns. In addition, most pregnant women who refused participation to our study, did not experience constipation as a medical problem during their pregnancy, but believed constipation is part of being pregnant. Another frequently heard reason for not participating in the study is that pregnant women experience their pregnancy as a stressful time and do not want to worsen this experience by participating in scientific research.
Another limitation of this study is the non-validated questionnaire used at baseline, which could have caused recall bias resulting in possible underreporting of defecation frequency per week and other defecation related parameters prior to the study. This could partly explain the initial increase in defecation frequency as shown in Figure1. But we assume the main effect observed in this study could be contributed to the mixture of probiotics. Besides, Pamuk et al. showed that the recall bias in questionnaires used to report defecation pattern is negligibly low .
The powder used in this study contains very small amounts of inuline and fructooligosaccharides (FOS). These inuline-type prebiotics are considered bifidogenic, stimulating the growth of Bifidobacterium species in the gut . Studies on the effect of these prebiotics on defecation frequency and consistency of stools, show conflicting results . However, it cannot be excluded that small amounts of prebiotics used in this study do have an additive effect on our results in the improvement of constipation symptoms. Future studies should address this issue.