Does greater morning sickness predict carrying a girl? Analysis of nausea and vomiting during pregnancy from retrospective report.

PURPOSE: The prevalence of severe nausea and vomiting during pregnancy (NVP) requiring hospitalization has been associated with female fetal sex. However, the question of whether fetal sex and less severe forms of NVP share that association has not been investigated. The objective of this study was to evaluate the relationship between fetal sex and the frequency of NVP. METHODS: We collected self-reported data from mothers via an international web-based survey on the Amazon Mechanical Turk (MTurk) platform about pregnancy and first trimester NVP history. We considered the covariables of maternal age, parity status, proneness to nausea, geographic cohort, and preconceived notions of a relationship between fetal sex and NVP. RESULTS: Two-thousand five hundred and forty-three mothers met the inclusion criteria, yielding data from 4320 pregnancies. Women gestating a female fetus reported higher frequencies of NVP (M = 6.35 on a 1-9 scale) than did women gestating males (M = 6.04, p = .007). This effect held true when all other variables were included in the regression. General proneness to nausea, maternal age, and parity were also significant independent predictors of NVP. CONCLUSIONS: Women that carried a female fetus, as opposed to a male fetus, reported significantly higher frequency of NVP during the first trimester of pregnancy. Further research should evaluate both the proximate and ultimate causes of this relationship.

Pharmacogenetic predictors of nausea and vomiting of pregnancy severity and response to antiemetic therapy: a pilot study.

BACKGROUND: Nausea and vomiting of pregnancy (NVP) is a common condition. The objective of this study was to evaluate the association between response to antiemetics in the treatment of NVP and genetic polymorphisms in the serotonin receptor subunit genes HTR3A and HTR3B. METHODS: Pregnant women ≥18 years of age with NVP starting antiemetic therapy with promethazine, prochlorperazine, metoclopramide, or ondansetron at ≤ 16 weeks gestational age were eligible. The study recruited 29 women with complete data and sampling who returned for their one week follow-up and were genotyped for HTR3A and HTR3B polymorphisms. Severity of NVP was captured (using Pregnancy Unique Quantification of Emesis (PUQE) and Quality of Life (QOL) tools) upon enrollment and after one week of antiemetic therapy. These measures were correlated with pharmacogenetic variability. RESULTS: Subjects with genotype associated with high serotonin affinity of the 5-HT3B receptor (rs1176744, CC) required more antiemetic medications (p < 0.001) than other subjects. Those with genotypes associated with increased expression of the 5-HT3A receptor subunit (rs1062613, CT or TT) had worse final PUQE scores (p = 0.01) than other subjects while rs3782025 variants carriers had significantly better initial (p = 0.02) and final (p = 0.02) PUQE scores than other subjects. CONCLUSIONS: HTR3B and HTR3A gene variants may contribute to variability in response to antiemetic therapy for NVP.

[Nausea and vomiting as evolutionary mechanisms of the complex adaptation reaction to pregnancy]. / Ubelkeit und Erbrechen als evolutionäre Mechanismen der vielschichtigen Anpassungsreaktion an die Schwangerschaft.

INTRODUCTION: Nausea and vomiting during pregnancy (NVP) constitute a frequent and often highly unpleasant syndrome during the sensitive period of early pregnancy, which has been intensively investigated. However, many questions remain unanswered, particularly the counterintuitive association with a better pregnancy outcome. Under these circumstances our functional concept to interpret NVP as an evolutionary mechanism of complex adaptation to early pregnancy seems promising. METHOD: In this cross-cultural study data were collected from 565 mothers, who had given birth recently in South Africa, Guatemala and Germany, using a standardised questionnaire interview. RESULTS: There was a cross-culturally similar prevalence and clinical presentation of NVP, showing a high degree of subjective suffering. We found evidence supporting a multifactoral aetiology of biological, psychological and sociological factors. Likewise, NVP seems to have multiple effects, concerning nutrition, behaviour, perception, psychology and social support. DISCUSSION AND CONCLUSION: Our new and previously existing data support the idea that NVP has been selected for by evolution, as a functional adaptation to vulnerable early pregnancy, which benefits mother and child. This assumption is supported by the correlation of NVP with a better foetal prognosis, the cross-culturally high prevalence and a favorable relation of low biological costs versus high effects. The benefit of NVP could be realised by nutritional change, increased social support, more passive and careful behaviour, earlier recognition of pregnancy and a positive influence on foetal development. To understand the functionality of NVP, one needs to consider the complex somato-psychoemotional interplay in the context of an environment of evolutionary adaptedness (EEA).