妊娠期恶心呕吐 (NVP) 的病因总体上仍然未知。研究和理论主要集中在三个领域:心理倾向性、进化适应性和激素反应。对 NVP 可能的心理病因进行的研究总数并未发现充分证据支持 NVP 是一种转换性障碍的理论。但该综述提到,有证据表明心理反应可能是起作用的因素。[6]Buckwalter JG, Simpson SW. Psychological factors in the etiology and treatment of severe nausea and vomiting in pregnancy. Am J Obstet Gynecol. 2002;186(5 Suppl):S210-S214.http://www.ncbi.nlm.nih.gov/pubmed/12011888?tool=bestpractice.com第二种假设是 NVP 代表了保护母体和胎儿不受潜在有害物质伤害的进化反应。[7]Sherman PW, Flaxman SM. Nausea and vomiting of pregnancy in an evolutionary perspective. Am J Obstet Gynecol. 2002;186(5 Suppl):S190-S197.http://www.ncbi.nlm.nih.gov/pubmed/12011885?tool=bestpractice.com大部分证据支持升高的激素水平会导致 NVP 的理论。已发现孕酮能减弱胃动力,并导致非妊娠女性出现恶心和呕吐。[8]Walsh JW, Hasler WL, Nugent CE, et al. Progesterone and estrogen are potential mediators of gastric slow-wave dysrhythmias in nausea of pregnancy. Am J Physiol. 1996;270:G506-G514.http://www.ncbi.nlm.nih.gov/pubmed/8638718?tool=bestpractice.com部分研究发现 NVP 与升高的人绒毛膜促性腺激素 (human chorionic gonadotrophin, hCG) 水平相关。[9]Masson GM, Anthony F, Chau E. Serum chorionic gonadotrophin (hCG), schwangerschaftsprotein 1 (SP1), progesterone and oestradiol levels in patients with nausea and vomiting in early pregnancy. Br J Obstet Gynaecol. 1985;92:211-215.http://www.ncbi.nlm.nih.gov/pubmed/3872132?tool=bestpractice.com其他研究表明, NVP 在具有较高雌二醇水平的女性中更为常见,而在具有较低雌二醇水平的女性中比较少见。[10]Bernstein L, Pike MC, Lobo RA, et al. Cigarette smoking in pregnancy results in marked decrease in maternal hCG and oestradiol levels. Br J Obstet Gynaecol. 1989;96:92-96.http://www.ncbi.nlm.nih.gov/pubmed/2923845?tool=bestpractice.com[11]Depue RH, Bernstein L, Ross RK, et al. Hyperemesis gravidarum in relation to estradiol levels, pregnancy outcome, and other maternal factors: a seroepidemiologic study. Am J Obstet Gynecol. 1987;156:1137-1141.http://www.ncbi.nlm.nih.gov/pubmed/3578425?tool=bestpractice.com最后,近期的一项系统评价显示幽门螺杆菌与妊娠剧吐存在关联。[12]Goldberg D, Szilagyi A, Graves L. Hyperemesis gravidarum and Helicobacter pylori infection: a systematic review. Obstet Gynecol. 2007;110:695-703.http://www.ncbi.nlm.nih.gov/pubmed/17766620?tool=bestpractice.com