To our knowledge, this is the first study to precisely characterize trimester-specific dietary intakes as well as diet quality in pregnant women with previous bariatric surgery. Energy intake did not differ significantly between groups. However, in women with previous surgery, there was a trend for energy intake to be higher with longer surgery-to-conception interval. During the third trimester, women with previous surgery consumed a significantly higher proportion of proteins than the control group. Conversely, carbohydrate as well as dietary fiber intakes for most women with previous surgery were below the recommendations and were significantly lower compared to the control group. Overall, women with previous surgery had a poorer diet quality compared to the control group.
Energy intakes did not differ significantly between women with and without bariatric surgery. This could be explained by the surgery-to-conception interval, which was greater than 18 months for 82% of the participants. The procedure associated with BPD and SG does involve a significant resection of the stomach volume and, consequently, a reduction in food intake, but mostly during the first months after the procedure. It is why it is generally recommended that women wait at least 12 months after a SG and 18 months after a BPD before conceiving [19, 20]. The lack of difference in energy intakes is similar to the findings of Jans et al., who noted no significant difference in energy intake (measured in the first and third trimesters) between women who became pregnant on average 45.6 months after surgery (mainly RYGB) and pregnant women without history of surgery [23]. In addition, in the present study, women with previous surgery tended to have higher energy intakes with increasing surgery-to-conception interval. As energy intakes appear to be influenced by the surgery-to-conception interval, healthcare professionals should consider this factor in nutritional monitoring of pregnant women with previous surgery.
In the third trimester, women with previous surgery reported a significantly greater proportion of energy intake from protein compared to the control group. Women with previous surgery may have been encouraged by health professionals to consume more protein-rich foods towards the end of their pregnancy, which could explain the difference observed between groups. Currently, there are no guidelines for specific macro- and micronutrient consumption for pregnant women with a history of surgery except for an unendorsed recommendation of a minimum daily protein intake of 60g, regardless of the surgical procedure [20, 24]. In the present study, women with previous surgery had protein intakes that were well above this recommendation. In contrast, daily protein intakes below 60g have been reported by Coupaye et al. in pregnant women with previous SG or RYGB while barely higher intakes were reported by Dias et al. in pregnant women with previous RYGB [25, 26]. The difference between their results and ours may be related to the type of surgery. Most women from our study had a BPD, a procedure known to induce a more pronounced protein deficiency than SG or RYGB, due to the short common limb [27]. Evaluating optimal protein requirements is a significant challenge for clinicians working with this population and the type of procedure should be considered in the elaboration of recommendations.
Carbohydrate and dietary fiber intakes of women with previous surgery were significantly lower than the control group and well below the DRI’s. Similar results were reported in Belgian pregnant women who had laparoscopic adjustable gastric banding (LAGB) or RYGB before pregnancy as well as in the non-pregnant bariatric populations [10, 28]. These results could be explained by the following: in the first post-surgery months, patients may have difficulty tolerating some complex carbohydrates and/or dietary fiber rich foods like bread, rice, pasta, vegetables and fruit skins [28]. Intolerances can persist for a few years after the procedure and may even cause food aversions [28]. Additionally, surgery can alter dietary preferences, which may also influence the patients’ food choices [29]. It is also of common practice to recommend that patients prioritize protein and micronutrient over starch intake after surgery [8, 24]. To date, the effects of a suboptimal carbohydrate intake on pregnancy outcomes in that population are under-studied.
Overall, diet quality of women with surgery was significantly lower than the control group in the first and second trimester. It is possible that food intolerances or aversions in women who had surgery influence dietary choices and therefore the overall diet quality [8]. Since the significant differences were observed for the adequacy components of the C-HEI, it could be hypothesized that food intolerances or aversions are more likely to affect ‘healthy’ foods. Indeed, the only components that differed significantly between groups was foods rich in complex carbohydrates or dietary fiber such as grain products and fruits and vegetables. According to some authors, being a younger and less educated woman is associated with a lower diet quality during pregnancy [30, 31]. In our study, women with previous surgery had a significantly lower level of education than the control group, which may partly explain the differences observed. Thus, food intolerances or aversions and the level of education of pregnant women with previous surgery should be considered when monitoring their diet quality.
Strength and limits
The use of a validated Web-based dietary assessment tool resulted in precise nutritional data at each trimester and the matched pairs design of the study considered the participants' pre-pregnancy BMI. Some limitations must be recognized including the small sample size and the large proportion of participants who did not complete the questionnaires at each trimester. Furthermore, the two types of surgery were not equally represented, which limits the generalization of our results. Moreover, supplement use was not assessed, which did not allow us to evaluate the real risks of micronutrients deficiencies. We did not have access to all medical records, which prevented us from assessing the association between diet and pregnancy outcomes. Finally, our study did not include questions about food intolerances or aversions developed following the operation.
What is already known on this subject?
Pregnant women with previous bariatric surgery are at greater risk of nutritional deficiencies but no study precisely characterized their eating habits at each trimester of pregnancy.
What this study adds?
This study showed that dietary intakes of pregnant women with bariatric surgery are suboptimal in terms of nutrient intakes and overall diet quality.