Sources of dietary recommendations and adherence to clinical guidelines in pregnant women in Germany | BMC Pregnancy and Childbirth

Out of the 4,351 women who began the survey, a total of 3,363 successfully completed it; thus, the completion rate was 77.00%. While 52.38% of the participants held academic qualifications, indicating a higher educational level than the average population, other characteristics such as age, BMI, and income closely mirrored the average German pregnant woman; thus, the results of the sample are deemed representative of the German pregnant population, with further details provided in Appendix 2 [55,56,57].

Table of Contents

Sources of dietary recommendations

Consultation by healthcare professionals

All 3,363 participants were asked about the extent to which they were advised by HCPs on nutrition and/or dietary supplements during their pregnancy. 52.10% (n = 1,031) of the respondents reported receiving “little” advice on nutrition during pregnancy, while 30.66% (n = 1,031) reported receiving no advice at all. By contrast, 13.74% (n = 462) of the participants reported receiving comprehensive advice, while only 3.51% (n = 118) reported receiving very comprehensive advice.

In summary, a majority of the pregnant women (> 80%) received little to no advice. At the same time, 68.66% (n = 2309) of the participants reported improving their diet since the beginning of their pregnancy compared to before. Thus, while most women did not receive professional guidance, two-thirds made changes to their dietary habits. Receiving (very) comprehensive advice was significantly correlated with other healthy lifestyle decisions. For instance, these women were more likely to exercise regularly during their pregnancy in the bivariate analysis (p < 0.001); however, in regression modeling this association was not statistically significant (OR = 1.08, 95% CI 0.90–1.30, p = 0.389). A consistent and significant effect was observed for dietary behavior: women receiving comprehensive advice more frequently reported paying attention to a healthy diet during pregnancy (OR = 1.59, 95% CI 1.24–2.06, p < 0.001). Additionally, a correlation was observed between the comprehensiveness of advice and reduced alcohol and nicotine consumption during pregnancy (both p < 0.001).

When participants indicated that they had received counseling from their HCP, they were requested to identify the specific provider. In response, 87.78% (n = 2,048) of respondents stated that the advice had come from an obstetrician or gynecologist. Midwives were the next most common source of dietary advice (34.33%, n = 801). Other medical professionals were comparatively less represented (Fig. 1). Within the “Others” category (n = 64), pharmacists were frequently cited; Only 1.69% (n = 57) of the pregnant women received advice from a nutrition specialist. Figure 1 presents the healthcare professionals providing dietary counseling within the sample.

Participants’ initiative in seeking nutritional information

Participants were also asked whether they had personally taken the initiative to inform themselves about nutrition and dietary supplements, which 80.79% (n = 2,717) of the women answered in the affirmative. A link between guidance from HCPs and personal initiative in seeking nutritional information was observed: Of those 118 women who received very comprehensive advice, 84.70% (n = 100) took the initiative to inform themselves further. This trend was consistent for women who received detailed (86.6%) or little advice (84.00%). Conversely, among women who received no advice from HCPs, only 72.20% had made the effort to inform themselves (p = 0.034).

Sources of information

Next, the participants were asked to identify their top three sources of information. As depicted in Fig. 2, 77.70% (n = 2,111) of the pregnant women primarily relied on Google searches for nutritional insights. Books and brochures followed as the second most frequently consulted source (53.81%, n = 1,462), while Internet forums were the third most popular source (33.24%, n = 903). Other sources of dietary information included friends and acquaintances (30.03%, n = 816), family members (15.02%, n = 408), and childbirth preparation courses (10.45%, n = 284). Moreover, 27.71% (n = 753) of the women turned to Instagram for guidance. By contrast, other social media platforms such as YouTube (6.55%, n = 178), Facebook (0.99%, n = 27), and TikTok (0.22%, n = 6) were used considerably less frequently. Figure 2 presents online and offline sources that were utilized by the participants to seek nutritional information.

Information quality and guideline conformity

Avoidance of foods

Participants were asked about the foods that they were advised to avoid and were given a list of 31 food items. Of these, current guidelines suggest that only nine are genuinely contraindicated during pregnancy [4, 22]. A significant proportion of participants indicated that they had received accurate advice regarding foods that pose potential health risks. Specifically, 95.33% (n = 3,206) were cautioned against consuming raw meat, 89.18% (n = 2,999) against unpasteurized milk and dairy, 92.42% (n = 3,108) against raw fish and seafood, and 85.16% (n = 2,864) against raw sausages (e.g., salami).

For other foods, however, the recommendations were less consistent. Only 44.37% (n = 1,492) of the participants were informed about the risks associated with wild game and offal, and a mere 25.33% (n = 852) were advised against beverages that contain quinine, such as tonic water and bitter lemon. The consensus was stronger regarding alcohol and nicotine, with 96.73% (n = 3,253) and 96.37% (n = 3,241) as well as Energy drinks with 72.79% (n = 2,448).

Noteworthily, some recommendations extended to foods that are not inherently hazardous during pregnancy. For instance, 31.22% (n = 1,050) were mistakenly cautioned against consuming coffee and 28.55% (n = 960) against consuming black tea. Furthermore, 19.30% (n = 649) were advised to abstain from sugar consumption, 16.06% (n = 540) received warnings about specific spices (e.g., cinnamon, cardamom, and cloves). Further items were honey (9.10%, n = 306), poppy seeds (9.66%, n = 325), and white flour products (13.53%, n = 455).

To examine these foods in more detail, we separately evaluated the number of foods avoided in alignment with the guidelines (termed “evidence-based avoidances”) and those avoided contrary to the guidelines (termed “non-evidence-based avoidances”).

Evidence-based avoidances

On average, expectant mothers were counseled to steer clear of almost seven (6.98; SD ± 1.53) of the nine foods that the guidelines recommend avoiding. There was no statistically significant difference based on educational levels (p = 0.06) or income levels (p = 0.08).

Furthermore, women who placed a higher emphasis nutrition during pregnancy or received comprehensive dietary counseling from HCPs were more accurately informed (7.03 vs 6.75, p < 0.001; 7.25 vs 6.93, p < 0.001, respectively). Midwife care was associated with the highest adherence (7.42 vs 4.95, p < 0.001), and self-informed participants also avoided more foods than those who did not (7.08 vs 6.54, p < 0.001; Fig. 3). Thorough details on this analysis can be found in the supplementary material (appendix 3). Figure 3 presents the number of evidence-based avoided foods in correlation to midwife care.

Non-evidence-based avoidances

In general, coffee was the food item mentioned the most (31.22%, n = 1,050), followed by black tea (28.55%, n = 960) and (refined) sugar (19.30%, n = 649). Figure 4 presents the 10 most frequently non-evidence-based avoided foods:

On average, the participants reported avoiding 1.88 (SD ± 2.1) foods that the guidelines do not explicitly caution against. In total, 20 foods on the provided list were not deemed necessary to completely avoid. Similar to the previous category, no significant differences were observed by education (academics: 1.93 vs non-academics: 1.83; p = 0.17) or income (below €2,500: 1.87 vs above €2,500: 1.89; p = 0.87). In contrast, women who prioritized a health-conscious diet, received comprehensive counseling, had midwife care, or self-informed about nutrition tended to avoid more non-evidence-based foods (1.96 vs 1.56; 2.07 vs 1.82; 1.99 vs 1.36; 2.04 vs 1.23; all p < 0.01).

Avoidance of foods for allergy prevention

Within the pregnancy cohort, women were questioned about food avoidance with the intention of allergy prevention. 25.48% (n = 857) of all participants indicated they had been advised or encountered this respective information during their self-informed endeavors.

This misinformation was associated with educational background and household income levels (see Fig. 5). Participants with higher income had a 31% lower likelihood of following such restrictions (OR = 0.69, 95% CI 0.56–0.85), and individuals with an academic degree a 35% reduced likelihood (OR = 0.65, 95% CI 0.55–0.77; p < 0.001). In contrast, women who received very comprehensive counseling from healthcare practitioners showed a pronounced inclination toward allergy prevention advice (39.83%, OR = 1.41, 95% CI 1.14–1.73; p < 0.001). The effect of midwife care remained nonsignificant (OR = 0.89, 95% CI 0.72–1.10; p = 0.07).

Intake of dietary supplements

Regarding the intake of dietary supplements during pregnancy, 89.03% of respondents (n = 2,994) reported either currently taking supplements or having taken them at some point during their pregnancy, while 10.97% (n = 369) did not.

Higher household income (> €2,500) was associated with 55% higher odds of supplement intake (OR = 1.55, 95% CI 1.18–2.03, p < 0.01), and women with an academic degree had 47% higher odds compared with those without (OR = 1.47, 95% CI 1.15–1.88, p < 0.01). Strong commitment to healthy eating was also a significant predictor (OR = 1.54, 95% CI 1.17–2.00, p < 0.01), as was receiving comprehensive nutritional counseling (OR = 1.59, 95% CI 1.12–2.31, p < 0.05). Self-initiated information seeking was the strongest predictor, tripling the odds of supplement use (OR = 3.26, 95% CI 2.54–4.18, p < 0.001). In contrast, alcohol consumption and smoking showed no significant influence (p = 0.86 and p = 0.26, respectively). Regular physical activity (OR = 1.17, 95% CI 0.90–1.52, p = 0.24) and midwife care (OR = 0.98, 95% CI 0.72–1.31, p = 0.88) were also not significantly associated with supplement intake (Fig. 6).

Intake of folic acid

Participants were instructed to specify the micronutrients in their supplements and to report the daily dosage directly from the packaging. Of the women who took dietary supplements (n = 2,994), 98.70% (n = 2,955) included folic acid, equating to 87.87% of all participants. This indicates that 408 women abstained from folic acid intake, contrary to guideline recommendations. The advised dosage varies depending on the time of initiation: 400 μg daily if commenced prior to pregnancy, or 800 μg upon the onset of pregnancy [4, 22]. However, a subset (n = 804) did not provide information on dosage or timing.

Overall, 40.71% (n = 1,369) of women adhered to the recommended dosage, 24.95% (n = 839) reported suboptimal intake, 22.21% (n = 747) supplemented without specifying dosage, and 12.13% (n = 408) did not supplement at all. This yields a conservative estimate that at least 40.71% met recommendations, while a minimum of 37.08% (n = 1,247) had insufficient intake. Figure 7 illustrates the distribution of folic acid supplementation within the sample.

Several factors were associated with folic acid supplementation. Women with higher household income (> €2,500) had greater odds of intake (OR = 0.67, 95% CI 0.53–0.84, p < 0.001), as did those who reported strong efforts toward a healthy diet (OR = 0.75, 95% CI 0.61–0.92, p = 0.005). Self-information was the strongest predictor, substantially increasing the likelihood of intake (OR = 0.54, 95% CI 0.43–0.68, p < 0.001). Academic education (OR = 0.84, 95% CI 0.70–1.01, p = 0.06), comprehensive counseling (OR = 0.87, 95% CI 0.70–1.08, p = 0.21), and midwife care (OR = 0.88, 95% CI 0.72–1.07, p = 0.19) showed no significant associations (Fig. 8).

Most women who supplemented with folic acid reported gynecologists as their primary source of advice (87.44%, n = 2,584), followed by midwives (27.72%, n = 819). Online information (26.76%, n = 791) and recommendations from family, friends, and peers (24.16%, n = 714) were also relevant sources.

Intake of iodine

Furthermore, participants reported whether they supplemented with iodine and, if applicable, specified their dosage. The primary source of the recommendation for iodine intake was their gynecologist, as noted by 1,434 participants. Overall, 66.10% (n = 2,223) of women reported taking iodine supplements, while 33.90% (n = 1,140) did not. Among those supplementing, 77.32% (n = 1,719) provided their specific dosage. Of these, 38.95% (n = 1,310) adhered to the recommended amount, whereas 12.16% (n = 409) reported suboptimal intake. The remaining 504 women (14.99%) supplemented without specifying their dosage, preventing exact evaluation (see Fig. 9). Taken together, these data allow a conservative estimate: at least 38.95% of participants supplemented with the recommended dosage, while insufficient intake is confirmed for the 224 women with suboptimal intake plus the 1,140 women who did not supplement at all. Conservatively combining these subgroups yields a minimum of 46.06% (n = 1,549) of women with inadequate iodine intake.

Comprehensiveness of professional counseling was strongly associated with iodine intake. Women who received comprehensive advice were more likely to supplement compared with those who received minimal or no guidance (p = 0.001). Notably, only 33.9% (n = 97) of women who neither received advice nor informed themselves took iodine, while supplementation was most frequent among women who both received professional advice and engaged in self-information (77.1%, p < 0.001). Midwife or nutrition specialist care was also associated with higher supplementation rates (both p = 0.001).

Binary logistic regression further highlighted that higher household income (> €2500; OR = 1.61, 95% CI [1.30–2.00], p < 0.001), comprehensive nutritional counseling (OR = 1.25, 95% CI [1.01–1.53], p = 0.037), and active self-information (OR = 2.36, 95% CI [1.90–2.95], p < 0.001) were significantly associated with iodine supplementation. In contrast, academic degree (OR = 1.16, 95% CI [0.99–1.37], p = 0.066), emphasis on a healthy diet (OR = 1.18, 95% CI [0.96–1.45], p = 0.125), and midwife care (OR = 1.13, 95% CI [0.92–1.40], p = 0.250) showed no statistically significant associations (Fig. 10).

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