The Effect of Maternal Diet on Neonatal Jaundice: A Case-Control Study

Summary

Objectives:

This study aims to investigate the influence of dietary heat intensity in maternal diets on the incidence of neonatal jaundice. Specifically, we examine whether maternal consumption of “dietary heat intensity” foods affects neonatal bilirubin levels, while controlling for potential demographic and obstetric confounding factors.

Methods:

This retrospective case-control study was conducted between October 2023 and September 2024. The study population consisted of mothers and their newborns attending healthcare centers in Alborz Province, Iran. Based on predefined inclusion and exclusion criteria, 152 newborns were enrolled, comprising 75 non-jaundiced and 77 jaundiced infants. Data were collected using an information-gathering form and a food frequency questionnaire. A total bilirubin level of ≥5 mg/dL was defined as the threshold for jaundice. The collected data were subsequently analyzed using SPSSv16 software.

Results:

Statistical analysis revealed significant differences between the two groups in several variables, including the number of pregnancies, delivery type, infant birth weight, gestational age, infant nutrition type, use of herbal medications in infants, and maternal age. Logistic regression analysis demonstrated a significant association between neonatal bilirubin levels and maternal consumption of “dietary heat intensity” foods, particularly warm-classified carbohydrates, fruits, and vegetables.

Conclusion:

The study results demonstrated that increased maternal consumption of hot-nature foods was significantly correlated with elevated bilirubin levels, suggesting a potential influence of maternal diet on neonatal jaundice incidence.

Advances in Knowledge

• This study highlights the crucial role of maternal dietary practices in influencing neonatal health outcomes, particularly about jaundice risk.

• These findings underscore the importance of healthcare providers prioritizing nutritional education for pregnant women, with a particular focus on dietary heat intensity and the selection of specific food groups.

• Through targeted nutritional guidance, healthcare professionals can promote healthier dietary behaviors that may reduce the incidence of neonatal jaundice and improve infant health outcomes.

Application to Patient Care

• This study revealed that the number of pregnancies, type of delivery, infant birth weight, gestational age, type of infant nutrition, use of herbal medications in infants, and maternal age differed significantly between neonates with jaundice and those without.

• This study showed that the heat intensity of maternal diet, overall intake, and consumption of warm-nature fruit groups (fruits, carbohydrates, and vegetables) during pregnancy could affect bilirubin levels in neonates.

1. Introduction

Neonatal jaundice is a prevalent clinical concern during the neonatal period, affecting approximately 80% of preterm infants and 60% of term infants.¹ Although hyperbilirubinemia is typically benign, severely elevated bilirubin levels may progress to kernicterus, potentially resulting in permanent neurological damage. The pathophysiology of neonatal hyperbilirubinemia involves three primary mechanisms: increased bilirubin production, impaired bilirubin elimination, and enhanced enterohepatic circulation, occurring either independently or in combination.² Despite its increasing prevalence, timely bilirubin monitoring and appropriate therapeutic intervention can substantially reduce the risks of kernicterus and neonatal encephalopathy, potentially preventing thousands of infant deaths worldwide.³ Primary prevention through risk factor modification represents the most critical intervention strategy prior to considering diagnostic and therapeutic approaches. Effective prevention requires the comprehensive identification of modifiable risk factors, thereby enabling targeted interventions to reduce the incidence of neonatal jaundice. However, the definitive etiological contributors to neonatal jaundice remain controversial within the scientific literature.⁴ Consequently, identifying modifiable risk factors associated with neonatal jaundice enables the implementation of targeted interventions to mitigate both its incidence and clinical severity.⁵

Predisposing factors for neonatal hyperbilirubinemia have been well-documented in the literature. Maternal-related risk factors include pregnancy complications such as gestational diabetes, hypertensive disorders (including preeclampsia), and preterm premature rupture of membranes.⁶ Additional established risk factors for neonatal hyperbilirubinemia include maternal-fetal blood group incompatibility, preterm birth, neonatal polycythemia, galactosemia, and sepsis. Furthermore, factors such as a family history of neonatal jaundice, postnatal hypernatremia with excessive weight loss, Asian ethnicity, and male sex have been consistently associated with increased hyperbilirubinemia risk.⁷ Genetic factors (UGT1A1 and G6PD variants),⁸ obstetric conditions (e.g., instrumental delivery, certain medications), administration of medications such as diazepam or oxytocin during labor, neonatal conditions (e.g., hypothyroidism, biliary anomalies, trisomy 21), environmental factors (e.g., altitude), and nutritional factors (e.g., breastfeeding difficulties), along with infections and hematologic disorders (e.g., spherocytosis, Gilbert syndrome) also contribute to risk.⁹ However, a crucial focus on the underlying etiological factors of this condition is warranted, particularly through an investigative lens that examines maternal behavioral patterns and lifestyle factors.¹⁰ Among these, dietary practices emerge as particularly significant. A comprehensive understanding of nutritional influences and their physiological effects is essential for maintaining homeostatic balance and optimal organ function.¹¹ During pregnancy, appropriate nutritional intake constitutes a critical determinant of health outcomes, with well-established links to (i) maternal wellbeing, (ii) fetal growth and development, and (iii) the mitigation of pregnancy-related complications and parturition risks.¹²

Bilirubin metabolism occurs primarily in the liver through conjugation by the enzyme uridine diphosphate-glucuronosyltransferase (UGT). Various nutritional factors can modulate the activity of this enzyme. Specifically, increased consumption of “hot-nature” foods may elevate serum bilirubin levels through two potential mechanisms: enhanced erythrocyte hemolysis or impaired hepatic elimination secondary to dietary-induced suppression of UGT activity.¹³ The dual classification of foods into “hot” and “cold,” which does not refer to temperature but rather to the quality of potential energy, suggests that “hot” foods are those that promote blood production, while “cold” foods, recognized for their low energy, counteract excess blood.¹⁴ Maintaining balance in the consumption of hot and cold foods is considered essential. Foods that possess both hot and cold characteristics are termed as “moderate” and are considered to have high nutritional value, with their consumption often recommended. Adherence to the hot/cold dichotomy varies according to season, gender, and life milestones.¹⁵

The traditional classification of foods into “hot” and “cold” categories includes items from both groups that may contribute to elevated bilirubin levels in newborns. Current evidence does not support the common assumption that exclusively hot-natured foods increase the risk of jaundice. The underlying mechanisms may involve either delayed intestinal motility, leading to enhanced enterohepatic bilirubin circulation, or inhibition of hepatic uridine diphosphate-glucuronosyltransferase (UGT) activity. Both pathways can reduce bilirubin clearance and consequently increase serum bilirubin concentrations.¹² Neonatal jaundice remains a clinically significant condition that is substantially influenced by sociocultural beliefs. Consequently, maternal understanding and perceptions of this condition play a crucial role in ensuring appropriate diagnostic evaluation, timely referral, adequate monitoring, and ultimately, favorable neonatal outcomes.³ The prevention of jaundice-related complications and promotion of infant health is strongly dependent on maternal health literacy, which encompasses knowledge, attitudes, perceptions, and healthcare-seeking behaviors related to this condition.¹⁶ Given both the high prevalence of neonatal jaundice and its potential for severe complications, this condition demands considerable clinical and public health attention.

Maternal beliefs that lead to the avoidance of certain foods may result in the exclusion of essential nutrients and micronutrients, potentially contributing to maternal and infant malnutrition and negatively impacting their overall health.¹⁷ Current scientific literature suggests that mothers should not experience dietary restrictions during pregnancy and lactation.¹⁸ Considering that both mothers and infants are vulnerable groups within the healthcare system, it is crucial to investigate maternal nutrition and the types of foods consumed during pregnancy, as well as the use of herbal remedies postpartum.¹⁹ This study aims to address the following research question: What is the relationship between the consumption of hot natural foods during pregnancy and bilirubin levels in newborns?

2. Methods

The present study is a retrospective case-control investigation designed to examine the impact of maternal diet on term infants within the first 15 days of life. The research was conducted at the pediatric clinics of Kamali and Imam Ali Hospitals, as well as affiliated health centers in Alborz Province, Iran. The study sample consisted of 152 mothers and their term infants who attended these healthcare facilities.

The inclusion criteria were as follows: term infants (defined as having a gestational age of ≥37 weeks), healthy, aged between 2 and 14 days, and exclusively breastfed. Infants younger than 2 days or older than 14 days were excluded to eliminate cases of jaundice attributable to pathological factors. For infants in the jaundiced group, hyperbilirubinemia was defined as a total serum bilirubin level exceeding 5 mg/dL.²⁰

The exclusion criteria included the presence of underlying medical conditions in infants (such as pathological jaundice occurring within the first 24 hours, enzymatic disorders, or ABO incompatibility), a birth weight of less than 2500 grams, any visible congenital anomalies on physical examination, lack of parental cooperation, incomplete maternal data regarding pregnancy or delivery, and maternal health conditions or medication use that could influence dietary intake or temperament.

The sample size for this study was determined based on the research conducted by Erjaee et al.¹² Using G*Power software, a confidence level of 95% and a statistical power of 80% were applied. Assuming a goodness-of-fit test with five degrees of freedom and a medium effect size of 0.3, the minimum required sample size was estimated to be 143 participants. To account for potential sample dropping, a total of 152 participants were enrolled, comprising 76 infants in each group.

The study was conducted from October 2023 to September 2024 and included two groups of term infants: those with physiological jaundice and those without. Dietary data were collected retrospectively through maternal recall, with a specific focus on dietary intake during the final two weeks of the third trimester of pregnancy.

Infants with physiological jaundice were identified through convenience sampling at the pediatric clinics of Kamali and Imam Ali hospitals in Alborz province. The researcher visited the clinics on various days and identified 77 eligible infants who met the inclusion criteria. To recruit healthy infants without jaundice, the health center's recording system was used to extract the contact information of mothers. After confirming eligibility based on the inclusion criteria, 75 infants who had not experienced jaundice by 15 days of age were enrolled as the control group at the health center.

2.1. Tools study

The research instrument comprised two distinct sections. The first (1) section included demographic characteristics of both mothers and infants and second (2) included maternal dietary intake during the final two weeks of pregnancy. These nutritional data were collected retrospectively through dietary recall interviews using a validated Food Frequency Questionnaire (FFQ), recognized as an instrument for evaluating long-term dietary patterns.²¹ This comprehensive tool assessed 86 food items, enabling the classification of participants according to their habitual food and nutrient consumption patterns. Mothers reported intake frequencies using standardized categories: daily (e.g., bread), weekly (e.g., rice, meat), monthly (e.g., fish), or never.

Mirmiran et al. evaluated the reliability and validity of the FFQ within the context of the Tehran Lipid and Glucose Study. Their findings demonstrated a high test-retest reliability coefficient (r = 0.81), indicating that the FFQ is a valid and reliable instrument for assessing dietary intake in Iranian populations.²²

In this questionnaire, food items are categorized into six distinct groups: (1) warm carbohydrates, fruits, and vegetables; (2) cold carbohydrates, fruits, and vegetables; (3) warm protein sources; (4) cold protein sources; (5) warm oils; and (6) cold oils. The frequency of consumption is classified on a scale from 1 (never) to 9 (four times a day or more). In this study, the “heat intensity” of food items consumed during the last month of pregnancy was classified into four categories. This classification was based on traditional dietary concepts rooted in Iranian culture²³ and Chinese medicine,²⁴ in which foods are categorized as “hot,” “cold,” or “moderate,” depending on their perceived physiological effects. Classification of foods by thermal properties in traditional Persian medicine is presented in Table 1. To quantify this concept, a numerical scoring system was developed, assigning values to food items based on traditional classifications and statistical quartile analysis: (1) scores ranging from 2–52 represented the cold group; (2) 53–64 the mildly cold group; (3) 65–76 the mildly warm group; and (4) 77–114 the warm group.

Table 1.

Classification of foods by thermal properties in traditional Persian medicine.

Category	Warm-nature foods	Cold-nature foods
Carbohydrates	Breads, pasta, snacks (chips, puffs), tea, sugar, salt	Rice, barley water, potatoes
Fruits	Grapes, apples, olives, bananas, melons, cherries, apricots, dates	Citrus fruits, watermelon, sour cherries, peaches, kiwi, pomegranate, plums
Vegetables	Fresh herbs, cooked greens, eggplant, celery, carrots, garlic, onions, bell peppers, cabbage	Squash, okra, cucumbers, tomatoes, lettuce
Protein Sources	Lamb, shrimp, organ meats (liver, tongue), processed meats, legumes (chickpeas, beans), walnuts, full-fat dairy	Beef, veal, fish, chicken, mushrooms, lentils, low-fat dairy
Oils/Fats	Solid vegetable oil, liquid vegetable oil, animal fat, butter	Mayonnaise

2.2. Statistical analysis

Following data collection, all information was entered into SPSS version 16 for statistical analysis. Descriptive statistics, including frequencies, means, and standard deviations, were calculated for each variable. Independent t-tests and chi-square tests were utilised to compare group differences. Additionally, regression analysis was conducted to evaluate the association between maternal nutrition and the occurrence of neonatal jaundice.

3. Results

The study population consisted of 152 neonates, comprising 78 females (51.3%) and 74 males (48.7%). Among jaundiced infants, the gender distribution was 36 females (46.2%) and 41 males (53.8%). Maternal age analysis revealed that 36% of mothers with jaundiced neonates were aged 26–30 years, compared to 32% of mothers in the non-jaundiced group [Table 2].

Table 2.

Comparative demographic characteristic in mothers and infants between two groups.

	Infants without jaundice	Infants with Jaundice
	n (%)		Confidence interval	P value
Number of pregnancies			1.004–1.042	0.05†
1	43 (57)	26 (33)
2	23 (30)	39 (50)
3	6 (8)	11 (14)
4	3 (4)	1 (1)
Mothers' blood type			0.79–1.81	0.7*
A+	24 (32)	23 (29)
A–	2 (2)	23 (29)
B+	20 (26)	1 (1)
O–	21 (28)	1 (1)
AB+	7 (9)	5 (6)
AB–	0 (0)	1 (1)
O+	1 (1)	23 (29)
Delivery type			1.045–1.83	0.02*
Natural delivery	22 (29)	24 (31)
C-section	53 (70)	53 (68)
Weight gain			0.92–1.07	0.41†
6–10	19 (25)	19 (24)
10.1–15	30 (40)	31 (40)
15.1–20	20 (26)	20 (25)
20.1–25	3 (4)	6 (7)
25.1–30	3 (4)	0 (0)
Birth weight			1.27–8.121	0.001*
2.5–3	55 (73)	75 (97)
3.1–3.5	16 (21)	1 (1)
>3.6	4 (5)	1 (1)
Gestational age			0.001–0.004	0.007*
38	48 (63)	67 (87)
39	18 (24)	6 (7)
40	9 (11)	4 (5)
Infants' nutrition			0.7–2.6	0.3*
Breast feeding	47 (62)	42 (54)
Breast feeding and milk powder	28 (37)	35 (45)
Infants' use of herbal medicine			1.45–7.89	0.04*
Yes	12 (16)	25 (33)
No	63 (84)	52 (67)
Jaundice child history in mothers			0.001–0.002	0.001*
Yes	12 (16)	31 (40)
No	63 (84)	46 (59)
Gender			0.76–2.7	0.25*
Girl	42 (56)	36 (46)
Boy	33 (44)	41 (53)
Mothers' age			0.02–2.27	0.31*
>20	6 (8)	1 (1)
21–25	11 (14)	5 (6)
26–30	24 (32)	28 (36)
31–35	25 (33)	21 (27)
<36	9 (12)	22 (28)
Mothers' education			0.63–2.27	0.59*
Illiterate	1 (1)	0 (0)
Diploma	36 (48)	41 (53)
Academic	38 (48)	36 (46)
History of disease			0.09–1.2	0.4*
Yes	48 (62)	47 (61)
No	27 (38)	30 (39)
Mothers' Employment			0.9–1.12	0.6*
Household	64 (85)	64 (83)
Employee	11 (14)	12 (15)
Student	0 (0)	1 (1)
Body mass index			0.85–1.006	0.37†
<18.5	5 (6)	2 (2)
18.6–24.4	36 (48)	31 (40)
25–29.9	24 (32)	29 (37)
>30	10 (13)	15 (19)
Maternal use of herbal medicine			0.27–1.004	0.12*
Yes	37 (50)	26 (34)
No	38 (50)	51 (66)
Infant' blood type			0.25–3.9	0.7*
A+	13 (17)	15 (19)	0.45–5.05
A-	7 (9)	6 (7)	0.18–2.2
B+	8 (10)	13 (16)	0.36–2.3
B-	12 (16)	7 (9)	0.34–16.6
O+	31 (41)	30 (38)	0.08–7.1
O-	2 (2)	4 (5)	0.25–3.9
AB+	2 (2)	2 (2)

^*Chi squared;

^†Independent T-test.

Statistical analyses revealed significant between-group differences in several key variables: number of pregnancies (p = 0.05), delivery type (P = 0.02), neonatal birth weight (P = 0.001), gestational age (P = 0.007), and infants' use of herbal medications (P = 0.04) [Table 2].

After confirming all assumptions for logistic regression and adjusting for significant confounders identified in bivariate analyses, the regression model revealed no significant associations between neonatal jaundice and infant blood group, gender, delivery type, or feeding method. However, we identified significant positive associations with three key variables: (1) herbal medication use in infants (OR = 1.22, P = 0.005); (2) birth weight (OR = –2.5, P = 0.03); and (3) reduced gestational age (OR = –1.64, P = 0.007) [Table 3].

Table 3.

The newborn jaundice prediction according to infant and maternal characteristics.

Jaundice	Odd ratio	Standard error	Confidence interval	P value
blood group
A-	0.99	0.7	0.25–3.9	0.99
B+	1.5	0.93	0.45–5.05	0.5
B-	0.65	0.41	0.18–2.2	0.51
O+	0.93	0.44	0.6–2.3	0.89
O-	2.3	2.3	0.34–16.6	0.38
AB+	0.79	0.88	0.08–7.1	0.83
Use of herbal medicine in infants	1.22	0.43	1.45–7.8	0.005
Birth weight	-2.5	1.16	1.27–8.21	0.03
Gender of the baby	0.37	0.32	0.76–2.7	0.25
Type of delivery	0.08	0.35	0.45–1.83	0.8
Birth rank	-0.38	0.22	0.44–1.04	0.08
Infants' nutrition	0.33	0.33	0.7–2.6	0.31
Maternal age	1.07	0.36	1.003–1.14	0.03
Gestational age	-1.64	0.59	-0.46– -2.82	0.007

The logistic regression analysis demonstrated no significant association between neonatal jaundice incidence and maternal demographic characteristics, including education, employment status, blood type, body mass index, gestational weight gain, maternal use of herbal medications, or number of pregnancies. However, higher maternal age showed a significant positive association (OR = 1.07, P = 0.03) [Table 3].

Linear regression analysis revealed significant positive associations between neonatal bilirubin levels and both: (1) overall consumption of “heat intensity” foods (β = 2.07, P = 0.04) and (2) warm-nature fruit intake specifically (β = 2.16, P = 0.03). In contrast, no significant associations were observed for warm-nature proteins, cold-ature proteins, warm-nature fats, cold-nature fats, or cold-nature fruits [Table 4].

Table 4.

Prediction of infant bilirubin levels according to maternal diet.

			Confidence interval
Food group	Standardized β	Unstandardized β	UPPER	LOWER	T value	P value
Heat intensity	2.07	5.9	0.78	0.0018	0.04	0.040
Warm protein	0.92	6.4	0.15	0.05	0.36	0.048
Cold protein	-0.28	8.9	-0.11	0.08	0.7	-0.013
Warm oil	0.47	7.6	0.27	0.17	0.6	0.052
Cold oil	-0.41	8.6	0.37	-0.57	0.6	0.099
Warm fruit	2.16	2.6	0.11	0.005	0.03	0.058
Cold fruit	0.2	7.9	0.11	-0.08	0.8	0.01
R2	0.03
Adjusted R2	0.0214

After adjusting for potential confounders (gestational age, maternal age, BMI, infant gender, and jaundice status), the linear regression model indicated that maternal dietary heat exposure significantly predicted neonatal bilirubin levels, a one-unit increase in dietary heat intensity associated with a 2.07 unit rise in bilirubin levels and explained 10% of the variance of bilirubin (adjusted R² = 0.10) [Table 5].

Table 5.

Prediction of infant bilirubin levels according to maternal diet with adjusted effect of maternal age, gestational age, jaundice, infant gender and body mass index.

		Confidence interval
Bill	Standardized β	UPPER	LOWER	T value	P value
Constant	65.05	11.2	18.8	2.78	0.006*
Heat intensity	0.040	0.07	0.002	2.11	0.03*
Maternal age	-0.003	0.15	-0.16	-0.05	0.96
Infant gender	0.60	2.18	-0.98	0.75	0.45
Gestational age	-1.6	-0.48	-2.82	-2.75	0.007
Jaundice	2.2	4.13	0.45	2.47	0.015*
BMI	0.09	0.13	-0.09	0.99	0.32
R2	0.13
Adjusted R2	0.10

BMI = body mass index.

4. Discussion

In this study, logistic regression analysis revealed significant associations between neonatal jaundice and several key variables: maternal age (OR = 1.07), infant use of herbal medications (OR = 1.22), baby's weight (OR = –2.5), and gestational age (OR = -1.64). Specifically, each additional year of maternal age was associated with a 7% increase in jaundice risk, while each week of gestational age reduced the odds by 64%. Similarly, every 1 kg decrease in birth weight increased the risk by 2.5 times higher, and infant herbal medication use was associated with a 22% reduction in the incidence of jaundice. Results of a study have demonstrated that 51.4% of jaundiced neonates were born to mothers aged >25 years. Moreover, low birth weight (<2500 g) and late preterm gestation (35–36 weeks) were identified as significant independent risk factors for neonatal hyperbilirubinemia.²⁵

This study revealed significantly higher herbal medication usage among jaundiced neonates compared to non-jaundiced infants (33% vs. 16%). Milk thistle and tragacanth were the most frequently administered herbal interventions. These findings reflect Iran's widespread cultural practice of using traditional herbal remedies for jaundice prevention, rooted in both historical medical traditions and contemporary physician recommendations. Notably, the observed association reflects a treatment-seeking bias rather than causal relationship, as infants with jaundice are more likely to receive herbal remedies. The higher prevalence of herbal supplement consumption among infants with jaundice or those considered at higher risk further supports the findings of this study.²⁶

A study identified milk thistle, tragacanth, chicory, and a combination of milk thistle and chicory as the top four therapeutic priorities used for infants diagnosed with jaundice.²⁷ Integrating traditional dietary practices with scientific research offers valuable insights into maternal and neonatal nutrition. This integrative approach is reinforced by recent studies that advocate for a culturally sensitive yet evidence-based framework. A framework that acknowledges the significance of traditional beliefs while promoting scientifically validated healthcare practices.²⁸ A systematic review further emphasized the importance of developing culturally sensitive dietary recommendations that integrate traditional beliefs with scientific evidence.²⁹

This study provides valuable insights into the relationship between maternal dietary patterns and the incidence of neonatal jaundice. The key findings suggest that increased consumption of “hot-natured” foods during pregnancy is positively correlated with elevated bilirubin levels in newborns. Specifically, the intake of warm-natured carbohydrates, fruits, and vegetables was found to be associated with higher bilirubin level, suggesting that maternal dietary choices may have a direct impact on neonatal health outcomes. After adjusting for potential confounders, sustained consumption of hot-nature foods was associated with a 2.1% increase in neonatal bilirubin levels.

A study conducted by Erjaee and colleagues examined the impact of maternal nutrition during the third trimester on total serum bilirubin levels in neonates. While the overall findings indicated no significant association between the general consumption of hot- or cold-natured food groups during the final trimester and neonatal bilirubin levels, further analysis of specific subcategories within these food groups revealed that certain items demonstrated a direct and statistically significant correlation with neonatal bilirubin concentrations.¹²

One study investigated the relationship between fatty acid content of maternal dietary and neonatal jaundice, concluding that variations in the fatty acid composition of maternal diets had no significant effect on bilirubin levels in neonates.³⁰ In contrast, a study conducted by Yi-Hao Weng et al., examined the association between maternal diets incorporating Chinese herbal medicines and prolonged jaundice in infants. The findings indicated that postpartum dietary practices involving Chinese herbal remedies were associated with breastfeeding-related jaundice.³¹ The study suggested that changes in maternal diet could alter the composition of breast milk, potentially contributing to prolonged jaundice among breastfed infants.

A study demonstrated that maternal consumption of capsaicin-rich diets which are analogous to traditional “hot” foods, led to a reduction in hepatic UDP-glucuronosyltransferase activity in neonatal rats.³² Similarly, the use of traditional “heating” herbs in Chinese diets was shown to alter neonatal gut motility patterns, supporting the hypothesis that enhanced enterohepatic circulation may contribute to elevated bilirubin levels in neonates.³³ In addition, a study investigating the role of epidermal growth factor (EGF) in human milk and maternal diet on late-onset breastfeeding jaundice found that dietary oils may influence the development of this condition by affecting EGF concentrations in breast milk.³⁴

One of the critical aspects of prenatal care pertains to dietary recommendations for mothers during pregnancy. While our hypothesis suggested that a higher intake of “hot nature” foods would increase bilirubin levels; it is essential to recognize that this relationship may not be universally applicable. Future research must investigate the complexities of dietary influences, as genetic predispositions, socioeconomic status, maternal health, and environmental variables may also significantly contribute to neonatal jaundice. One limitation of this study was its retrospective design, which may have introduced recall bias. Therefore, Future research should prioritize longitudinal studies that evaluate the impact of maternal diet over time, including postpartum dietary practices and their effects on breastfeeding and infant health. In addition, investigating the mechanisms underlying dietary influences on bilirubin metabolism will be essential, particularly regarding the roles of specific nutrients and their interactions with one another.

Furthermore, expanding the demographic scope of future studies to encompass more diverse populations may enhance the generalizability of the findings. Another limitation of the study was that categorizing food items based on “heat intensity” may not fully capture the complexity of dietary patterns across different regions of Iran, thereby limiting the applicability of our findings to other populations. The statistical analysis determined a minimum sample size of 152 participants in our study for the generalizability of the findings. This highlights the need for further research with larger and more diverse samples to validate our results. We suggest that further studies also assess additional contributing factors to neonatal jaundice.

5. Conclusion

This study highlights the significant role of maternal dietary choices in influencing neonatal bilirubin levels and the incidence of jaundice. By raising awareness about the potential effects of consuming “hot-natured” foods during pregnancy, healthcare providers can more effectively support maternal and infant health, ultimately contributing to a reduction in the prevalence of neonatal jaundice.

Authors' Contribution

Sara E. Saeieh: Conceptualization, Methodology, Supervision, Writing - Original Draft. Marzieh Mahdipoor: Conceptualization, Methodology, Investigation, Writing - Review & Editing. Alireza J. motlagh: Validation, Resources, Writing - Review & Editing. Hamid S. Baghbanan: Conceptualization, Methodology, Writing - Review & Editing. Zohreh Khodaii: Conceptualization, Writing - Review & Editing. Mahmood Bakhtiyari: Formal analysis, Methodology, Writing - Review & Editing.

Acknowledgement

The authors would like to thank the Kamali Research and development center, Alborz University of Medical Sciences, for their cooperation, as well as all the participants.

Ethics Statement

The study was approved by the Ethics Committee of Alborz University of Medical Sciences (Approval Code: IR.ABZUMS.REC.1402.118) and conducted by the principles outlined in the Declaration of Helsinki. Participants' parents or legal guardians were provided with both written and verbal information regarding the study's purpose and procedures. Informed consent was obtained prior to participation. Participation was entirely voluntary, and guardians were informed of their right to withdraw from the study at any time without any consequences.

Conflict of Interest

The authors declare no conflicts of interest.

Funding

This study was funded by Alborz University of Medical Sciences.

Data Availability

Data is available upon reasonable request from the corresponding author.