怀孕早期恶心呕吐可能降低孕妇流产风险
不少孕妇被恶心、呕吐这些孕期反应折磨得苦不堪言，不过可以感到欣慰的是，孕妇呕吐可能意味着流产风险比较低。
2016年9月26日，《美国医学会杂志》内科医学分册在线发表美国卫生研究院（NIH）、犹他大学健康科学中心、美国医疗研究与质量管理署（AHRQ）、以色列海法大学的随机临床研究二次分析，发现怀孕早期恶心呕吐与孕妇流产风险降低有相关性。
该研究追踪调查了2007年6月15日～2011年7月15日在4家美国临床中心797位曾经流产1～2次的孕妇（平均年龄28.7±4.6岁），其中188位孕妇（23.6%）以流产而告终。恶心、恶心伴呕吐分别使流产风险降低50%、75%。
该研究并未深入探究恶心、呕吐降低流产风险的原因，但是哈佛医学院、贝斯以色列女执事医疗中心的专家认为，恶心感会让孕妇减少进食，从而减少胚胎接触毒素的风险；此外，减少进食也会降低身体循环中胰岛素水平，促进胎盘生长。
JAMA Intern Med. 2016 Sep 26. [Epub ahead of print]
Association of Nausea and Vomiting During Pregnancy With Pregnancy Loss: A Secondary Analysis of a Randomized Clinical Trial.
Hinkle SN, Mumford SL, Grantz KL, Silver RM, Mitchell EM, Sjaarda LA, Radin RG, Perkins NJ, Galai N, Schisterman EF.
National Institutes of Health, Bethesda, Maryland; University of Utah Health Sciences Center, Salt Lake City; Agency for Healthcare Research and Quality, Rockville, Maryland; University of Haifa, Haifa, Israel.
IMPORTANCE: Nausea and vomiting during pregnancy have been associated with a reduced risk for pregnancy loss. However, most prior studies enrolled women with clinically recognized pregnancies, thereby missing early losses.
OBJECTIVE: To examine the association of nausea and vomiting during pregnancy with pregnancy loss.
DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial, Effects of Aspirin in Gestation and Reproduction, enrolled women with 1 or 2 prior pregnancy losses at 4 US clinical centers from June 15, 2007, to July 15, 2011. This secondary analysis was limited to women with a pregnancy confirmed by positive results of a human chorionic gonadotropin (hCG) test. Nausea symptoms were ascertained from daily preconception and pregnancy diaries for gestational weeks 2 to 8. From weeks 12 to 36, participants completed monthly questionnaires summarizing symptoms for the preceding 4 weeks. A week-level variable included nausea only, nausea with vomiting, or neither.
MAIN OUTCOMES AND MEASURES: Peri-implantation (hCG-detected pregnancy without ultrasonographic evidence) and clinically recognized pregnancy losses.
RESULTS: A total of 797 women (mean [SD] age, 28.7 [4.6] years) had an hCG-confirmed pregnancy. Of these, 188 pregnancies (23.6%) ended in loss. At gestational week 2, 73 of 409 women (17.8%) reported nausea without vomiting and 11 of 409 women (2.7%), nausea with vomiting. By week 8, the proportions increased to 254 of 443 women (57.3%) and 118 of 443 women (26.6%), respectively. Hazard ratios (HRs) for nausea (0.50; 95% CI, 0.32-0.80) and nausea with vomiting (0.25; 95% CI, 0.12-0.51) were inversely associated with pregnancy loss. The associations of nausea (HR, 0.59; 95% CI, 0.29-1.20) and nausea with vomiting (HR, 0.51; 95% CI, 0.11-2.25) were similar for peri-implantation losses but were not statistically significant. Nausea (HR, 0.44; 95% CI, 0.26-0.74) and nausea with vomiting (HR, 0.20; 95% CI, 0.09-0.44) were associated with a reduced risk for clinical pregnancy loss.
CONCLUSIONS AND RELEVANCE: Among women with 1 or 2 prior pregnancy losses, nausea and vomiting were common very early in pregnancy and were associated with a reduced risk for pregnancy loss. These findings overcome prior analytic and design limitations and represent the most definitive data available to date indicating the protective association of nausea and vomiting in early pregnancy and the risk for pregnancy loss.
TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00467363.
PMID: 27669539
DOI: 10.1001/jamainternmed.2016.5641
JAMA Intern Med. 2016 Sep 26. [Epub ahead of print]
Toward a Deeper Understanding of Nausea, Vomiting, and Pregnancy Loss.
Nippita S, Dodge LE.
Beth Israel Deaconess Medical Center, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.
PMID: 27669337
DOI: 10.1001/jamainternmed.2016.6101
