Vaginal delivery and longer labor duration tied to food sensitization in infants: Study
Japan: Vaginal delivery (VD) is associated with an increased risk of food sensitization (FS) in infancy, a recent study in Annals of Allergy, Asthma & Immunology has claimed. Further, longer labor duration may also promote the development of food sensitization. Considering the lack of clarity on the effects of delivery mode and labor duration on FS development in infancy,...
Japan: Vaginal delivery (VD) is associated with an increased risk of food sensitization (FS) in infancy, a recent study in Annals of Allergy, Asthma & Immunology has claimed. Further, longer labor duration may also promote the development of food sensitization.
Considering the lack of clarity on the effects of delivery mode and labor duration on FS development in infancy, Tetsuhiro Sakihara, Department of Pediatrics, Heartlife Hospital, Okinawa, Japan, and colleagues aimed to elucidate the potential effects of delivery mode and labor duration on FS development by 6 months of age.
For this purpose, the researchers performed a case-control trial of 462 participants who had undergone the final assessment at 6 months of age using data from a randomized controlled trial of a birth cohort from 4 Japanese hospitals that assessed cow's milk allergy development by 6 months of age.
Food sensitivity was defined as positive skin prick test reactions to cow's milk, hen's egg, wheat, or soy. For the primary outcome, the researchers calculated the adjusted odds ratio of VD relative to cesarean delivery for the development of food sensitivity by 6 months of age using multivariable logistic regression analysis. For the secondary outcome, labor duration was compared between participants with and without FS using the Mann-Whitney U test.
Key findings of the study include:
- The infants born through vaginal delivery tended to have a higher gestational age, with a higher proportion of them not ingesting any CMF in their first 3 days of life. Also, they had a lower parental age at delivery and lower maternal BMI before pregnancy.
- At age 6 months, the infants born through vaginal delivery had significantly higher incidences of food sensitization and hen's egg sensitization as indicated by one or more positive SPT reactions compared with those born through cesarean delivery.
- The researchers did not find any significant differences in sensitization incidences to cow's milk, wheat or soy.
- 1.5% of the infants had developed cow's milk allergy by age 3 months, including 1.1% of those delivered vaginally and 2.6% of those with cesarean delivery. By age 6 months, the overall proportion was 4.1%, with 4.2% among those delivered vaginally and 3.7% of those with cesarean delivery.
- The incidence of food sensitization development by 6 months of age was significantly higher in vaginal delivery-born infants than in CS-born infants. This positive association between vaginal delivery and food sensitization development remained statistically significant even after adjusting for other parental, perinatal, and environmental factors.
- Infants with food sensitization experienced significantly longer labor durations with a median of 5.7 hours (interquartile range [IQR], 2.7-10.1), compared with those without food sensitization, who experienced a median of 4.5 hours (IQR, 1.1-8.2).
- A significant association was found between longer labor durations and a higher proportion of infants with food sensitization as well.
- Infants born through vaginal delivery further experienced an adjusted odds ratio of 2.75 for hen's egg sensitization and 1.98 for cow's milk sensitization.
- The infants with hen's egg sensitization experienced significantly longer labor duration, with a median of 5.7 hours (IQR, 3.4-10.5) compared with those without hen's egg sensitization, who had a median of 4.5 hours (IQR, 1.1-8.2).
- There was no significant difference in the duration of labor between those infants who had cow's milk sensitization (median, 4.5 hours; IQR, 2.3-10.5) and those who did not (median, 4.7 hours; IQR, 1.9-9).
- Among the 169 infants who did not have any siblings, there was no significant difference in the duration of labor between infants with food sensitization (median, 9.1 hours; IQR, 4.9-14.3) and those without (median, 9.1 hours; IQR, 4.7-16.1).
- Among infants with one or more siblings, those with food sensitization had significantly longer labor (median, 4.2 hours; IQR, 2.4-6.1) compared with those who did not have food sensitization (median, 3.1 hours; IQR, 0-5.3).
To conclude, the researchers add, "there is a need for additional prospective cohort studies to assess the relationship between labor duration and food sensitization or food allergy development in larger community-based populations over longer follow-up periods."
Sakihara T, Yasuki D, Otsuji K, Arakaki Y, Hamada K, Sugiura S, Ito K. Effects of delivery mode and labor duration on the development of food sensitization in infancy. Ann Allergy Asthma Immunol. 2022 Apr 21:S1081-1206(22)00306-4. doi: 10.1016/j.anai.2022.04.008. Epub ahead of print. PMID: 35460868.