Here’s what morning sickness during pregnancy really means

Good news!

"Key takeaways

• A UCLA study has found that “morning sickness” symptoms, including nausea, vomiting and aversions to certain foods and smells, are linked to the body’s natural, but complex, immune response during pregnancy.
• In the early stages of pregnancy, a unique mix of inflammatory responses alongside behavioral mechanisms that researchers believe are adaptive, like nausea, achieves a delicate balance, allowing the mother to tolerate and nourish the half-foreign fetus while also avoiding potentially harmful foods.
• The study could have workplace implications for pregnant women, helping to widen recognition that these symptoms are healthy and normal, both reducing stigma and paving the way for common-sense workplace accommodations.

... According to the National Institutes of Health, up to 80% of early-stage pregnant mothers experience some nausea, vomiting and aversions to certain foods and smells. While uncomfortable, these symptoms are not typically a sign that anything is wrong with the health of the mother or the developing fetus, but rather an indication of a delicate balance unique to pregnant women.  ..."

From the abstract:

"Background

During pregnancy, the maternal body undergoes extensive physiological adaptations to support embryonic growth, including whole-body remodeling, that may induce odor and food aversions, as well as nausea and vomiting. The biological mechanisms behind odor and food aversions, as well as nausea and vomiting in early pregnancy, remain largely unexplored. Our study investigated associations between these changes and cytokine profiles during pregnancy.

Methodology

A cohort of pregnant Latina women in Southern California (n = 58) completed a structured questionnaire on pregnancy “morning sickness”-related symptoms and aversions. Maternal plasma cytokine levels were measured between 5 and 17 weeks’ gestation.

Results

About 64% of participants experienced odor or food aversions, primarily to tobacco smoke and meat; 67% reported nausea, and 66% experienced vomiting. Multivariable linear regression models revealed that odor aversions were associated with increased pro-inflammatory T-helper-cell type (Th) 1 composite cytokine levels.

Women who found tobacco smoke aversive exhibited a shift toward Th1 immune responses, indicated by a higher Th1:Th2 ratio.

Food aversions also showed a positive association with Th1 cytokine levels. A borderline positive association was noted between nausea and vomiting and the Th1:Th2 ratio.

Conclusions

These findings are consistent with the hypothesis that gestational changes in olfactory and gustatory experience, and nausea and vomiting, reflect adaptive upregulation of behavioral prophylaxis in ways that could protect the fetus. If this elevated Th1:Th2 ratio and pro-inflammatory phenotype are part of the maternal and embryonic response to embryogenesis, the behavioral and biological markers that we explore may provide an accessible index of fetal development during early pregnancy."

Here’s what morning sickness during pregnancy really means | UCLA "UCLA’s latest findings show how a woman’s healthy inflammatory response during pregnancy is linked with unpleasant early-stage symptoms"

Of scents and cytokines: How olfactory and food aversions relate to nausea and immunomodulation in early pregnancy (open access)

Fig. 1 A conceptual model of the behavioral and immunological changes during pregnancy. Note: The intensity/sensitivity levels depicted are not based on specific observational data but are provided to facilitate a structured understanding of the phenomena under investigation, grounded in empirical evidence