Nausea and vomiting of pregnancy (NVP) is so common that both health care providers (HCPs) and pregnant women often downplay its effects on the pregnancy.1 However, NVP is not simply a medical condition of pregnancy; it can also become a quality of life (QOL) issue. The symptoms may cause emotional distress and interfere with a woman’s ability to maintain her daily routines and responsibilities, including work and familial commitments and social obligations.
Despite the prevalence of NVP and its potential negative effects on QOL, the topic has received little attention. An extensive review of English-language literature between 1999 and 2011 identified only 87 articles addressing NVP and QOL.2 The research was done in various countries, with only a few studies coming from the United States.
In recent years, researchers have attempted to quantify the severity of NVP and its impact on QOL. Canadian researchers adapted the Rhodes scale, which was designed to assess nausea and vomiting in patients receiving chemotherapy, to create the Pregnancy-Unique Quantification of Emesis (PUQE) scoring system.3 This scoring system addresses the clinical severity of NVP, in addition to including an overall assessment of well-being in a 12-hour period. The same group subsequently modified and validated the PUQE scoring system to assess symptoms during a 24-hour period.4 The PUQE score considers 3 parameters: the length in hours of nausea and the frequency of vomiting and of retching episodes. A numerical value ranging between 1 and 5 is assigned to each of these 3 parameters. A total score of 3 represents freedom from symptoms; a score of 4 to 6 indicates mild NVP; a score of 7 to 12 signifies moderate NVP; and a score of 13 to 15 is considered severe NVP. The PUQE assessment also asks women to rate their overall well-being on a scale of 0 to 10, with 10 being the best.
The PUQE score is mainly an assessment of the severity of NVP. Although the well-being question looks broadly at QOL, researchers have sought a more detailed assessment of the impact of NVP on QOL. Some have used general QOL assessments, such as the Medical Outcomes Study Short Form Health Survey (SF-36), which has 36 items spanning 8 domains,5 or the abbreviated 12-item Short Form Health Survey (SF-12), which has 2 summary scores.6 Other researchers have developed NVP-specific QOL instruments. One that has been validated is the NVPQOL instrument developed in Canada.7,8
To gain more perspective on NVP and to quantify its impact on QOL in women in the United States, the National Voice of Pregnancy survey was conducted among 621 women currently or recently pregnant who experienced NVP. Findings from the survey were reviewed by a multidisciplinary panel that met in Philadelphia, Pa, in March 2013. This article presents the survey results and discusses them in relation to previous reports on NVP and QOL. In addition, strategies for HCPs to improve patient interactions and discussion of NVP symptoms are suggested.
NATIONAL VOICE OF PREGNANCY SURVEY
To obtain more insight into the experience of women with NVP, an online survey was commissioned by Duchesnay USA and conducted by National Analysts Worldwide in October and November 2012. The survey covered a range of topics pertaining to NVP, including the timing and pattern of symptoms and their impact on daily life. The goal was to gain in-depth understanding of the full effects of NVP from the patient’s perspective. The ultimate objective was to help HCPs better manage this condition and minimize the consequences on QOL.
Pregnant and recently pregnant women in the United States were recruited from the Survey Sampling International consumer Web panel. Respondents who met the inclusion criteria completed a self-administered, online questionnaire, which took 30 minutes. Previous qualitative research among pregnant women with NVP informed the questionnaire design. Participants were asked about their pregnancy, prenatal care, family and work environments, and demographics. Areas of inquiry specific to NVP included symptom severity, progression, and variability as assessed by the PUQE scoring metric, which was adapted to accommodate more open-ended retrospective reporting (ie, “on days when you were experiencing symptoms” rather than “in the past 24 hours”); interactions with HCPs regarding NVP; and the impact of NVP on QOL in personal and occupational domains. The QOL areas covered were similar to those measured by standard QOL instruments, with emphasis on points deemed important for NVP and pregnancy as opposed to disease states.
Findings were analyzed for patterns and relationships based on potentially relevant variables, including age, symptom severity, and provider type. Symptom severity emerged as most predictive of the variables considered and therefore became the main focus in data reporting.
Tests of statistical significance were applied to the findings based on assumptions about panel recruitment, method of sampling from within the panel frame, and overall representativeness. Comparisons were considered significant at the 95% confidence level. The results may be considered statistically representative of US women with NVP who were pregnant between May and November 2012.
Women between 18 and 50 years old who, based on prior data obtained by the Survey Sampling International Web panel, were thought to be pregnant or to have recently given birth were invited to participate in the survey. Those who responded were screened to establish whether they met the other study criteria (were at least 16 weeks pregnant or had given birth within the past 6 months, had experienced nausea and/or vomiting during their current or recent pregnancy, and had received routine prenatal care). Of the 1698 women eligible, 621 completed the survey.
Quotas were set to ensure representation of both currently pregnant and recently pregnant women across the entire spectrum of NVP severity, as determined by PUQE score. The final sample comprised 297 currently pregnant women and 324 who had given birth within the past 6 months. This was the first pregnancy for 51% of the study population. As determined by PUQE score, 106 women (17%) had mild NVP, 492 (79%) had moderate NVP, and 23 (4%) had severe NVP. Because of the small number of women with severe NVP, results for the 515 women with moderate or severe NVP are reported together.
Table 1 summarizes demographic characteristics of the study sample. It is included to further describe the study population. No conclusions can be drawn between the demographic patterns and survey results.
Limitations of this survey relate mainly to the sampling method. By definition, a Web panel is not a true probability sample because it excludes people who do not have access to computers for survey-taking purposes or do not chose to participate in them. (It is estimated that well >85% of the age-relevant, English-speaking population has Internet access.) Those limitations notwithstanding, studies based on Web panels can be considered representative of the specified universe insofar as samples can be recruited on a random or probability basis from very large, geographically balanced sample frames. For this reason, Web panels are widely used in commercial and public policy research to produce statistically generalizable data.
Consistent with known epidemiology, a small number of respondents reported having severe symptoms of NVP (23/621). As a result, it was necessary to aggregate responses for women who reported severe symptoms with those who experienced moderate symptoms. No statistically robust comparisons can be made between women in the severe category and those with either mild or moderate symptoms. Another limitation of the study was a matter of timing: participants were often reporting on symptoms experienced some months earlier (ie, during an earlier trimester or a recent pregnancy). As a result, there may have been some recall bias, with distorted memory of the severity of symptoms or the effect on QOL. Finally, another drawback of Web panels—especially English-language panels—is that they tend to underrepresent minorities. This demographic bias was seen in the National Voice of Pregnancy survey, where 75% of the respondents characterized themselves as non-Hispanic white.
Despite these limitations, the survey findings provided data consistent with past reports about NVP. The survey also yielded important new information, especially about communication between HCPs and pregnant patients.
SYMPTOMS OF NVP
Of the 621 women who met the criteria for inclusion in the study, 99% experienced nausea and 73% vomiting; 52% reported dry heaving, gagging, or retching. Other commonly reported symptoms included breast tenderness (reported by 91%), indigestion or heartburn (83%), and constipation (68%).
On average, symptoms of NVP began at 7.7 weeks. In women with moderate to severe NVP, symptoms occurred slightly earlier, at an average of 7.3 weeks; in women with mild NVP, symptoms began later at 8.8 weeks. Nearly 4 (77%) of every 5 women began to experience symptoms before their first prenatal visit. Survey respondents reported that symptoms were at their worst at about 12 to 13 weeks, began to subside between 18 and 20 weeks, and ended between 22 and 24 weeks. Symptoms lasted an average of 15 weeks and were of shorter duration in women with mild NVP (13 weeks) than in those with moderate/severe NVP (16 weeks).
When the most severe symptoms occurred and what each woman considered the most bothersome symptom varied among respondents. Most women (63%) reported that nausea and vomiting were worst in the morning. About one fourth (23%) of women with moderate or severe NVP reported that symptoms were worst at night. Nearly twice as many women considered nausea more bothersome than vomiting (39% vs 21%), whereas 41% rated the 2 symptoms equally bothersome. Women whose PUQE scores qualified as mild NVP were more likely than those with moderate/severe scores to be disturbed more by vomiting (27% vs 19%). However, when this analysis was performed in relation to women’s self-perception of symptoms rather than the PUQE score, women who self-rated their symptoms as mild were much more likely to be troubled by nausea than vomiting, presumably because they vomited less frequently.
Overall, 20% of survey respondents reported going to the hospital because of NVP symptoms. As could be expected, the percentage that sought hospital care increased with the severity of symptoms. Although treatment usually was in the emergency department, 38% of women who sought hospital care were admitted. Hospital care included intravenous fluids (82%) and antiemetics (72%). The average visit to the hospital was 3 times longer for patients with moderate/severe symptoms as for those with mild NVP, 63 versus 21 hours.
The findings of this survey fall within ranges for prevalence and symptom patterns of NVP seen in previously published studies and reviews. Most women experience nausea, with or without vomiting, in the early months of pregnancy. Symptoms begin in the first or second month, peak around 9 to 15 weeks, and resolve in the second trimester. Although commonly referred to as “morning sickness,” NVP can occur at any time of day or night.9,10
In large studies across the globe, specific numbers vary but show similar trends. Lacasse et al,11 studying 367 Canadian women, found that 78.5% had NVP in the first trimester, with 52.2% reporting mild symptoms, 45.3% moderate, and 2.5% severe. Among 396 Chinese women, Chan et al12 found that 9.1% had no symptoms of NVP, whereas symptoms were mild in 37.6%, moderate in 51.8%, and severe in 1.5%. Studying 593 Australian women, Smith et al13 reported that 90% had symptoms of NVP before 6 weeks’ gestation, with nausea much more common and distressing than vomiting. Magee et al,7 in a study of 500 Canadian women, also found that women were bothered more by nausea than vomiting and suggested that may be because nausea lingers but vomiting brings relief.
IMPACT OF NVP ON QOL
Responses in the National Voice of Pregnancy survey demonstrated that NVP affects QOL in multiple ways. The impact is greater in women with moderate or severe symptoms, but the lives of women with mild NVP also may be compromised. Eating, sleeping, ability to perform daily routines at home and at work, interpersonal relationships, and enjoyment of the pregnancy experience may be affected.
As could be anticipated, NVP greatly impacted respondents’ eating and nutrition (Table 2). Nearly all women with moderate/severe NVP (87%) indicated that the condition diminished their pleasure in eating, as did 69% of those with mild NVP. Many women were concerned that NVP made it difficult to eat nutritiously, a concern expressed much more frequently by those with moderate/severe NVP (74%) than those with mild symptoms (41%). Just over half (54%) of women overall (60% with moderate/severe NVP and 40% with mild symptoms) indicated that they were unable to take or keep down prenatal vitamins and felt this further compromised their nutritional status and that of their developing fetus. Some women (44% overall; 51% with moderate/severe NVP; 26% with mild) thought NVP made it hard for them to gain weight during pregnancy.
Sleep was often compromised by NVP, especially among women with moderate/severe symptoms. Overall, 61% of respondents indicated that NVP interfered with their ability to get a good night’s sleep. This was a problem for 67% of women with moderate/severe NVP, compared with 47% of those with mild NVP.
Lack of sleep and nutrition may have contributed to or magnified the impact of NVP on daily functioning. Table 3 summarizes some changes in the domestic and social aspects of QOL. Overall, 71% of respondents (79% of those with moderate/severe NVP compared with 52% of those with mild symptoms) reported difficulty performing household chores. Almost half of the women overall said that NVP compromised their ability to take care of themselves as well as their children and other dependents. As a result, burden shifted to the spouse, according to 61% of the total sample. Although domestic functioning was hampered more by moderate/severe NVP, even mild NVP limited the ability to fulfill family responsibilities for a large percentage of survey respondents.
Social life was also affected by NVP, as shown in Table 3. The most commonly reported social limitations were enjoyment of activities with family and friends, the desire to be socially active, the ability to concentrate, and spousal intimacy. These were diminished in about two-thirds of the sample overall and in 3 of every 4 women with moderate/severe symptoms. Patience, interest in life, and planning ability were often decreased by NVP, as reported by 54% to 63% of respondents overall, 62% to 69% of those with moderate/severe symptoms, and 36% to 49% of those with mild NVP.
About 2 of every 5 respondents (46% with moderate/severe NVP, 21% with mild) had difficulty driving or using public transportation. Absence from work and tardiness were common; women were late to work on a mean of 5 days because of “morning sickness” and missed an average of 9 full days of work as a result of their NVP. This sometimes meant loss of pay. Most women reported reduced productivity and anxiety about their performance on the job. Some women felt that NVP had a negative impact on their relationships with peers or superiors or on their careers overall. As with other QOL issues, work-related effects were greater in women with moderate/severe NVP than in those with mild symptoms (Table 4).
Under ideal circumstances, pregnancy should be an enjoyable experience, but NVP tended to lessen the pleasure (Table 5).
More than two thirds of all survey respondents (three fourths of women with moderate/severe symptoms, half of those with mild) reported that NVP diminished their general enjoyment of pregnancy. Some women, especially those with moderate/severe symptoms, reported anxiety about the health of the baby and lacked confidence that they were doing the best they could for their unborn child. According to 32% of the total population (41% of women with moderate/severe symptoms), NVP forced them to reveal their pregnancies to coworkers or family members sooner than they had planned. Some women who had NVP questioned whether they would want to go through pregnancy again.
Regardless of the assessment method used, studies have demonstrated that NVP greatly impacts QOL. Effects have been found in all 8 domains measured by the SF-36 (physical functioning, physical role functioning, bodily pain, general health perceptions, vitality, social functioning, emotional role functioning, and mental health).12–15 As the severity of NVP worsened, so did the effects on QOL.12 A Canadian study using the shorter SF-12 revealed similar results, with significant decreases in both the physical and mental component summary scales.11 Assessment with the population-specific NVPQOL tool, which has 4 domains (physical symptoms and aggravating factors, fatigue, emotions, and limitations),8 also demonstrated that NVP diminishes QOL, with scores on the NVPQOL worsening as the severity of NVP increased.11
Researchers around the globe have compared QOL in women with NVP and in other populations. Mean scores on the SF-36 were worse than population norms for women in the United States in all 8 domains, with the greatest effect on social functioning.14 An Australian researcher noted that scores on the SF-36 were similar to those in patients with chronic illnesses.13 Lacasse et al11 found that Canadian women with moderate and severe NVP had physical component summary scores on the SF-12 similar to those reported for women with breast cancer,16 and women with the worst symptoms had scores on the mental component summary scale approaching those reported for women with postpartum depression.17
Other effects of NVP on mental health have been noted. More than half of the 273 pregnant women in a study from England had scores on a validated psychometric questionnaire suggestive of potential psychiatric problems, and the scores for anxiety and depression correlated with the severity of NVP.18 Although a causal relationship was not established in that study, a correlation between NVP severity and anxiety and depression also was seen in a study of 230 Turkish women, none of whom had evidence of psychological problems before pregnancy.19 While evidence that NVP is caused by a conversion disorder or abnormal response to stress has been called “questionable at best,”1 it may be that NVP induces symptoms of anxiety and depression in some women. The relationship between NVP and psychiatric problems may merit further study.
The survey also demonstrated that NVP poses a risk to the pregnant woman’s ability to work outside the home. The effect of NVP on working life has been documented in previous studies as well, although the specific findings vary, perhaps because of sampling procedures or societal norms. In a multicenter study in the United States, women who worked outside the home reported losing an average of 14 days of work because of NVP.14 More than one fourth (27%) of Chinese women took at least 1 day of sick leave because of NVP during their first trimester, and 7.3% required 7 or more days off.12 The impact was even greater in an Australian study, which reported that 55% of the women had to take time off from work because of NVP; in addition, 28% had to change their work schedules, and 4% quit their jobs. Approximately two thirds of the women in that study thought they were less attentive at work.13
Finally, the severity of NVP has, in rare cases, been found to lead to voluntary termination of pregnancy. A report from Canada noted that 17 of 1100 women interviewed terminated otherwise wanted pregnancies because of severe NVP, and another 42 women considered this option to put an end to the symptoms.20
Participants in the National Voice of Pregnancy survey reported trying a variety of methods to relieve symptoms of NVP. The women received suggestions for dietary and other nonpharmaceutical approaches from friends, family, the Internet, and HCPs. Among these management techniques were the following: eating throughout the day, including a little before getting out of bed, drinking fluids frequently, eating carbohydrates, avoiding spicy foods, and using ginger. Nearly all women (94%) tried at least 1 such remedy to help relieve NVP, but few found them beneficial.
One fourth (24%) of the survey respondents said they never mentioned their symptoms of NVP to their HCPs. Women with moderate or severe symptoms were more likely to have a conversation with their HCPs about NVP (82% vs 62% of those with mild symptoms). Nearly 4 (37%) in 10 women reported waiting until their first prenatal visit, which generally occurs at weeks 6 to 10, to tell their HCP about their symptoms, and 51% waited until a later visit. In other words, the first discussion about NVP with a professional frequently occurred well into the first trimester, long after the onset of symptoms.
When presented with a list of reasons for not mentioning NVP to their HCP, more than half (53%) of the women selected “I thought these symptoms are a natural result of pregnancy and did not need to be addressed.” A much smaller group (9%) said they did not discuss NVP because they knew they would abstain from using medication. Among those who did tell their HCP about their NVP, 41% wanted suggestions to remedy the problem, and 23% were hoping for a prescription to manage the symptoms. One (24%) of every 4 women was looking for reassurance from their HCP. Concern about the health of the unborn child prompted 30% of the women to raise the subject, whereas worry about their own health was a motivating factor for 21%.
The vast majority (85%) of women indicated that their HCP asked if they were experiencing NVP, whether or not the interaction qualified for patients as a “discussion.” (For 16% of them, it did not.) The conversation centered on the frequency and severity of symptoms and what the patient had already tried to minimize them. Only 37% reported that their HCP asked about the impact of NVP on their life.
Overall, HCPs recommended over-the-counter (OTC) medication for 43% of the survey respondents and prescription medication for 58%, whereas 29% did not receive medication recommendations. Prescriptions were written for 64% of women with moderate or severe symptoms and 36% of those with mild NVP. Although 32% of patients expected medications would completely eliminate NVP, 23% thought they would just take the edge off the symptoms, and 45% assumed they would improve symptoms enough to feel substantially better. Overall, 79% of respondents expressed satisfaction with OTC or prescription medications.
One strength of the National Voice of Pregnancy survey is the gathering of data on interactions between pregnant women and their HCPs regarding NVP. This is an area that has not been covered in depth in the literature. More information about when and how women communicate with their HCPs about NVP is important because of the variety of approaches to management of symptoms.
Dietary and lifestyle modifications are usually the first approach to relieve symptoms of NVP. However, there is little published evidence of the efficacy of dietary measures and other nonpharmacologic approaches for the management of NVP.1,10,21 For example, small trials of acupuncture22,23 and P6 (Neiguan point) acupressure24,25 or nerve stimulation26 yielded conflicting results.
Two natural substances that have the best documented results in the management of NVP are ginger and vitamin B6 (pyridoxine). A systematic review of 6 double-blind, randomly controlled trials of ginger concluded that it may be safe and effective.27 Pyridoxine is so effective that the American College of Obstetrics and Gynecology recommends it as the starting point of pharmacologic management for NVP.1
To guide clinicians in pharmacologic treatment of NVP, the American College of Obstetrics and Gynecology produced an algorithm (that begins with pyridoxine alone or in combination with the antihistamine doxylamine). These agents have been proven to be both safe and effective in the management of NVP,1 and each is available OTC in the United States. Pyridoxine and doxylamine are the only medications commonly used for treatment of NVP that have received Food and Drug Administration category A labeling for use in pregnancy, meaning that controlled studies have shown no risk to the fetus.10 Should this combination fail to provide adequate relief, promethazine or dimenhydrinate may be added. Other medications are available for refractory cases.1
Until 1983, a fixed-dose combination of pyridoxine and doxylamine was available in the United States (Bendectin; Merrelll Dow Pharmaceuticals, Kansas City, Mo). The manufacturer voluntarily withdrew the product from the market because of lawsuits claiming that it caused birth defects. Scientific evidence has not supported these claims.28 Furthermore, the rates of birth defects overall and of any particular type have not decreased since sale of Bendectin ended, as would be expected if the drug were teratogenic.29 The fixed combination continued to be sold in Canada in a delayed-release formulation, and a randomized, double-blind, multicenter trial there demonstrated significant improvement in PUQE scores compared with placebo.30 Based on these data, the Food and Drug Administration recently approved marketing of a delayed-release fixed-dose combination of pyridoxine and doxylamine for the management of NVP (Diclegis; Duchesnay USA, Rosemont, Pa).
HOW HCPS CAN MINIMIZE THE IMPACT OF NVP ON QOL
Both data from the National Voice of Pregnancy survey and published findings provide evidence that even mild NVP can diminish a pregnant woman’s QOL. The effects are magnified when symptoms are moderate or severe.
Many women suffer from NVP and its effects on their daily lives without optimum symptom management. A more proactive approach by HCPs can help address those symptoms, improve QOL, and result in a better pregnancy experience.31
Early discussion about NVP, empathy and support of the patient experiencing these symptoms and their effects, and safe and effective treatment are all important. Below are suggested interventions for HCPs.
Provide Education About Symptoms of NVP and Its Consequences
Some women want reassurance that their symptoms are a normal part of pregnancy. However, HCPs also should advise women that symptoms can worsen and become severe enough to require hospitalization and should explain when seeking medical care is necessary. When HCPs acknowledge that NVP can diminish QOL, especially in severe cases, patients may be better prepared to handle the changes and to ask for assistance as needed. Informational sheets or pamphlets outlining symptoms, consequences, and possible remedies can help improve patient knowledge. Women might want to share the written information with their family, friends, and coworkers.
Specifically Inquire About the Effects of NVP on QOL
Almost two thirds of the respondents in the National Voice of Pregnancy survey whose HCPs asked about NVP reported that the professional failed to inquire about the effect of symptoms on their daily activities. This represents a missed opportunity not only for improving the experience of the pregnant patient, but also for implementing a treatment plan early so symptoms do not progress. Clearly, NVP involves more than physical symptoms. It has far-reaching effects on QOL in many domains: performance of daily household and occupational activities, sleep, relationships with family and friends, and mental health. By inquiring about these effects on QOL, the HCP addresses the patient as a whole, not just her physical symptoms.
Open Lines of Communication Early
Women need to know they can seek information and management recommendations from their HCPs, rather than turn to folk remedies, Web sites, and other potentially useless or even harmful information. Because symptoms of NVP often occur before the first prenatal visit, discussion about NVP ideally takes place even earlier. If a patient tells her provider that she is planning to get pregnant, the HCP can assure her the door is always open for questions and concerns.
One way a practice can help ensure optimal management of NVP is to designate a phone contact, such as a nurse, who is available for questions. This person can address the concerns of patients before their first scheduled prenatal visit. Encouraging follow-up by phone enables HCPs to monitor any changes and concerns, regardless of the severity of NVP.
Provide Customized Treatment
A “one-size-fits-all” approach does not work for treating NVP. Symptoms tend to be worst in the morning but may peak at nighttime in some women and interfere with sleep. Symptoms are mild for some, severe for others. Although some women refuse to consider pharmacologic treatment, others welcome the relief that comes with early medical intervention and the resulting ability to resume ordinary routines.
Obtaining patient history about onset, timing, duration, and severity of symptoms, along with precipitating and alleviating factors, can help HCPs customize treatment strategies. In addition, HCPs should inquire about changes in QOL. Good clinical management should also consider patient preferences. For many women, the choice will be medication that alleviates symptoms and causes no harm to the fetus.
Nearly all pregnant women experience NVP, especially in the first trimester. The extent of symptoms varies from one woman to another, as does the effect on QOL. The impact can be far-reaching, altering a pregnant woman’s domestic, social, and occupational life, as well as her physical and mental well-being. The effect of NVP on QOL is worse in severe cases, but women with mild symptoms may still be negatively impacted. To help patients through this stressful period, HCPs should ask about symptoms and how they have changed daily life. Dietary modifications and safe and effective medications can ease the symptoms of NVP and help restore QOL.
The authors acknowledge the support of Duchesnay USA for sponsorship of this survey. In addition, the authors appreciate and acknowledge the support and input of National Analysts Worldwide and Paul Bianchi of MedEdNow.
1. American College of Obstetricians and Gynecologists. Nausea and vomiting of pregnancy. ACOG practice bulletin no. 52. Obstet Gynecol. 2004; 103: 803–815.
2. Wood H, McKellar LV, Lightbody M. Nausea and vomiting in pregnancy: blooming or bloomin’ awful? A review of the literature. Women Birth. 2013; 26: 100–104.
3. Koren G, Boskovic R, Hard M, et al. Motherrisk-PUQE (Pregnancy-Unique Quantification of Emesis and Nausea) scoring system for nausea and vomiting of pregnancy. Am J Obstet Gynecol. 2002; 186 (suppl 5): S228–S231.
4. Ebrahimi N, Maltepe C, Bournissen FG, et al. Nausea and vomiting of pregnancy: using the 24-hour Pregnancy-Unique Quantification of Emesis (PUQE-24) scale. J Obstet Gynaecol Can. 2009; 31: 803–807.
5. Ware JE Jr, Sherbourne CD. The MOS 36-item short-form health survey (SF-36): I. Conceptual framework and item selection. Med Care. 1992; 30: 473–483.
6. Ware JE Jr, Kosinski M, Keller SD. A 12-item short-form health survey: construction of scales and preliminary tests of reliability and validity. Med Care. 1996; 34: 220–233.
7. Magee LA, Chandra K, Mazzotta P, et al. Development of a health-related quality of life instrument for nausea and vomiting of pregnancy. Am J Obstet Gynecol. 2002; 186 (suppl 5): S232–S238.
8. Lacasse A, Bérard A. Validation of the nausea and vomiting of pregnancy specific health related quality of life questionnaire. Health Qual Life Outcomes. 2008; 6: 32–37.
9. Clark SM, Costantine MM, Hankins GDV. Review of NVP and HG and early pharmacotherapeutic intervention [published online ahead of print November 24, 2011]. Obstet Gynecol Int. Epub November 24, 2011.
10. Niebyl J. Nausea and vomiting in pregnancy. N Engl J Med. 2010; 363: 1544–1550.
11. Lacasse A, Rey E, Ferreira E, et al. Nausea and vomiting of pregnancy: what about quality of life? B J Obstet Gynaecol. 2008; 115: 1484–1493.
12. Chan OK, Sahota DS, Leung TY, et al. Nausea and vomiting in health-related quality of life among Chinese pregnant women. Aust NZ J Obstet Gynaecol. 2010; 50: 512–518.
13. Smith C, Crowther C, Beilby J, Dandeaux J. The impact of nausea and vomiting on women: a burden of early pregnancy. Aust NZ J Obstet Gynaecol. 2000; 40: 397–401.
14. Attard CL, Kohli MA, Coleman S, et al. The burden of illness of severe nausea and vomiting of pregnancy in the United States. Am J Obstet Gynecol. 2002; 186 (suppl 5): S220–S227.
15. Munch S, Korst LM, Hernandez GD, et al. Health-related quality of life in women with nausea and vomiting of pregnancy: the importance of psychosocial context. J Perinatol. 2011; 31: 10–20.
16. Winefield HR, Coventry BJ, Pradhan M, et al. A comparison of women with breast cancer who do and do not seek support from the internet. Aust J Psychol. 2003; 55: 30–34.
17. Da Costa D, Dritsa M, Rippen N, et al. Health-related quality of life in postpartum depressed women. Arch Womens Ment Health. 2006; 9: 95–102.
18. Swallow BL, Lindow SW, Masson EA, et al. Psychological health in early pregnancy: relationship with nausea and vomiting. J Obstet Gynaecol. 2004; 24: 28–32.
19. Köken G, Yilmazer M, Cosar E, et al. Nausea and vomiting in early pregnancy: relationship with anxiety and depression. J Psychosom Obstet Gynecol. 2008; 29: 91–95.
20. Mazzota P, Magee L, Koren G. Therapeutic abortions due to severe morning sickness. Can Fam Phys. 1997; 43: 1055–1057.
21. Mazzotta P, Magee LA. A risk-benefit assessment of pharmacological and nonpharmacological treatments for nausea and vomiting of pregnancy. Drugs. 2000; 59: 781–800.
22. Carlsson CPO, Axemo P, Bodin A, et al. Manual acupuncture reduces hyperemesis gravidarum: a placebo-controlled, randomized, single-blind, crossover study. J Pain Symptom Manage. 2000; 20: 273–279.
23. Knight B, Mudge C, Openshaw S, et al. Effect of acupuncture on nausea of pregnancy: a randomized, controlled trial. Obstet Gynecol. 2001; 97: 184–188.
24. Dundee JW, Sourial FBR, Ghaly RG, et al. P6 acupressure reduces morning sickness. J R Soc Med. 1988; 81: 456–457.
25. O’Brien B, Relyea MJ, Taerum T. Efficacy of P6 acupressure in the treatment of nausea and vomiting during pregnancy. Am J Obstet Gynecol. 1996; 174: 708–715.
26. Rosen T, de Veciana M, Miller HS, et al. A randomized controlled trial of nerve stimulation for relief of nausea and vomiting in pregnancy. Obstet Gynecol. 2003; 102: 129–135.
27. Borrelli F, Capasso R, Aviello G, et al. Effectiveness and safety of ginger in the treatment of pregnancy-induced nausea and vomiting. Obstet Gynecol. 2005; 105: 849–856.
28. Hale RW, Niebyl J. Bendectin: how a safe and effective drug was removed from the market by our legal system. Clin Rev. 2012; 17: 25–27.
29. Koren G, Pastuszak A, Ito S. Drugs in pregnancy. N Engl J Med. 1998; 338: 1128–1137.
30. Koren G, Clark S, Hankins GDV, et al. Effectiveness of delayed-release doxylamine and pyridoxine for nausea and vomiting of pregnancy: a randomized placebo controlled trial. Am J Obstet Gynecol. 2010; 203: 571.e1–571.e7.
31. Ebrahimi N, Maltepe C, Einarson A. Optimal management of nausea and vomiting of pregnancy. Int J Womens Health. 2010; 2: 241–248.
© 2013 by Lippincott Williams & Wilkins.