Morning Sickness Is Mother Nature's Way of Protecting Mothers and Their Unborn, Cornell Biologists Find (Cornell University)
"As unpleasant as it is, the nausea and vomiting of "morning sickness" experienced by two-thirds of pregnant women is Mother Nature's way of protecting mothers and fetuses from food-borne illness and also shielding the fetus from chemicals that can deform fetal organs at the most critical time in development."
Rates of Nausea and Vomiting in Pregnancy and Dietary Characteristics Across Populations (PubMed)
"Nausea and vomiting in pregnancy (NVP) is a pervasive and debilitating phenomenon in humans. Several adaptive explanations for NVP occurrence have been recently proposed, the two most prominent of which predict associations with nutritional intake or specific dietary components. Here we extend previous cross-cultural analyses by analyzing associations between NVP prevalence in 56 studies (21 countries) and quantitative estimates of per capita intake across major dietary categories, measured for the year of study by the Food and Agriculture Organization (FAO)."
Nausea and Vomiting of Pregnancy in an Evolutionary Perspective (PubMed)
The proximate mechanisms underlying gestational nausea and vomiting have been intensively studied, but the possibility that the symptoms themselves serve a useful function has only recently been considered seriously. We synthesized evidence to evaluate various hypotheses for the adaptive significance of nausea and vomiting of pregnancy, as well as the possibility that symptoms are nonfunctional byproducts of pregnancy hormones.
Severity and Duration of Nausea and Vomiting Symptoms in Pregnancy and Spontaneous Abortion (PubMed)
"Earlier studies have shown an inverse association between the presence of nausea and vomiting in pregnancy (NVP) and spontaneous abortion (SAB), but no study to date has examined the effects of symptom duration on the risk of SAB.We examined NVP symptom severity and duration in relation to the occurrence of SAB. Data were collected from 2407 pregnant women in three US cities between 2000 and 2004 through interviews, ultrasound assessments and medical records abstractions."