Physiology & Behavior 69 (2000) 259–267 0031-9384/00/$ – see front matter © 2000 Elsevier Science Inc. All rights reserved. PII: S0031-9384(00)00223-7 Bitter taste perception and severe vomiting in pregnancy M.L. Sipiora a , M.A. Murtaugh b , M.B. Gregoire c , V.B. Duffy d, * a Rush-Presbyterian-St. Luke’s Medical Center, Dept. of Employee Wellness, Chicago, IL 60612 b University of Minnesota, School of Public Health, Minneapolis, MN, 55454 c Iowa State University, Hotel, Restaurant, Institution Management, Ames, IA 50011 d University of Connecticut, School of Allied Health, Storrs, CT 06269, USA Received 8 February 1999; received in revised form 27 October 1999; accepted 7 December 1999 Abstract Hyperemesis gravidarum or severe vomiting during pregnancy is a condition of elusive etiology that can harm both mother and fetus. This study examined the association between increased bitter-taste perception and history of hyperemesis gravidarum. Bitter-taste per- ception varies genetically and can be altered with conditions that damage taste-related cranial nerves. Sixty women were divided into high- (n = 21) and low-vomit (n = 39) groups based on vomiting exposure across all pregnancies and were screened for genetic variation in taste with bitterness of saturated 6-n-propylthiouracil (PROP) delivered on filter paper. Supertasters perceive PROP as intensely bit- ter; nontasters, as only weakly. Each reported their history of dysgeusia (persistent taste) and taste-related pathology (otitis media and head trauma). The vomit groups did not differ in the frequency of supertasters, but the high-vomit group had fewest nontasters. The high- vomit group also reported dysgeusia most frequently. A subsample (13 high-vomit and 18 low-vomit women) rated the taste intensity of sodium chloride (1 mol), sucrose (1 mol), citric acid (0.0032 mol), and quinine hydrochloride (0.001 mol) applied to areas innervated by cranial nerves VII and IX. The groups only varied significantly in bitterness of quinine hydrochloride. High-vomit women tasted least bit- terness on the anterior tongue (chorda tympani branch of VII) and highest bitterness on the posterior tongue (cranial nerve IX) and pal- ate (superficial petrosal branch of VII). In high-vomit women, elevated bitterness on the posterior tongue and palate does not appear re- lated to hydrochloric acid exposure in vomitus; it may explain the occurrence of dysgeusia. This pattern of spatial taste perception may indicate altered oral sensations that if present during pregnancy, could increase the risk of hyperemesis. © 2000 Elsevier Science Inc. All rights reserved. Keywords: Hyperemesis gravidarum; dysgeusia; taste; 6-n-propylthiouracil; nausea and vomiting; pregnancy 1. Introduction In a typical healthy pregnancy, 50 to 90% of women ex- perience morning sickness or mild nausea and vomiting [38]. Up to 1% of all births, however, are from pregnancies with severe nausea and vomiting [24], a condition termed hyperemesis gravidarum. Severe and prolonged vomiting can induce maternal weight loss, electrolyte imbalances, and dehydration, conditions that may necessitate hospital- ization [17,28,33,56]. In 1996, over 60,000 women were ad- mitted to a hospital for hyperemesis gravidarum [26]. Un- controlled hyperemesis gravidarum and the associated consequences risk the health of both mother and developing fetus and increase costs of prenatal care. The etiology of hy- peremesis gravidarum is largely unknown and probably multifactorial. Historically, psychosexual and psychiatric problems were hypothesized as contributors to excessive nausea and vomiting during pregnancy, but these theories are not supported by sound empirical evidence (see [36] for a review). A study of the physiological factors that may contribute to severe vomiting during pregnancy is needed to understand this complex disorder. Heightened oral sensations may be an antecedent or con- sequence of severe nausea and vomiting during pregnancy. As an antecedent, excessive bitter-taste perception during pregnancy could increase feelings of disgust from eating, especially if coupled with other oral sensory alterations such as hypersalivation [25] or heightened somatosensory sensations to stimulate gag responses and the need to vomit. Women predisposed to intense oral sensations may be par- ticularly vulnerable to negative affective cues during preg- nancy, when oral sensations may be further enhanced. As a consequence, the acid exposure from vomiting during preg- nancy could damage taste receptors and, if severe enough, could result in damage that persists after the pregnancy. The following provides support for these statements. Taste and somatosensory sensations are closely inte- grated in the oral cavity. Whole-mouth taste perception is * Corresponding author. Tel.: 860-486-1997; Fax: 860-486-1588. E-mail address: valerie.duffy@uconn.edu