Is hyperemesis gravidarum associated with placental weight and the placental weight-to-birth weight ratio? A population-based Norwegian cohort study

Emerging Progress in Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum: Challenges and Opportunities

Nausea and vomiting of pregnancy (NVP) is a common condition that affects up to 70% of pregnant women. Hyperemesis gravidarum (HG) is considered the serious form of NVP, which is reported in 0.3–10.8% of pregnant women. NVP has a relatively benign course, but HG can be linked with some poor maternal, fetal, and offspring outcomes. The exact causes of NVP and HG are unknown, but various factors have been hypothesized to be associated with pathogenesis. With the advance of precision medicine and molecular biology, some genetic factors such as growth/differentiation factor 15 (GDF15) have become therapeutic targets. In our review, we summarize the historical hypotheses of the pathogenesis of NVP and HG including hormonal factors, Helicobacter pylori, gastrointestinal dysmotility, placenta-related factors, psychosocial factors, and new factors identified by genetics. We also highlight some approaches to the management of NVP and HG, including pharmacological treatment, complementary treatment, and some supporting treatments. Looking to the future, progress in understanding NVP and HG may reduce the adverse outcomes and improve the maternal quality of life during pregnancy.

Nausea and vomiting of pregnancy and hyperemesis gravidarum

Nausea and vomiting of pregnancy (NVP) is a common condition that affects as many as 70% of pregnant women. Although no consensus definition is available for hyperemesis gravidarum (HG), it is typically viewed as the severe form of NVP and has been reported to occur in 0.3-10.8% of pregnant women. HG can be associated with poor maternal, fetal and child outcomes. The majority of women with NVP can be managed with dietary and lifestyle changes, but more than one-third of patients experience clinically relevant symptoms that may require fluid and vitamin supplementation and/or antiemetic therapy such as, for example, combined doxylamine/pyridoxine, which is not teratogenic and may be effective in treating NVP. Ondansetron is commonly used to treat HG, but studies are urgently needed to determine whether it is safer and more effective than using first-line antiemetics. Thiamine (vitamin B1) should be introduced following protocols to prevent refeeding syndrome and Wernicke encephalopathy. Recent advances in the genetic study of NVP and HG suggest a placental component to the aetiology by implicating common variants in genes encoding placental proteins (namely GDF15 and IGFBP7) and hormone receptors (namely GFRAL and PGR). New studies on aetiology, diagnosis, management and treatment are under way. In the next decade, progress in these areas may improve maternal quality of life and limit the adverse outcomes associated with HG.

Maternal vomiting during early pregnancy and cardiovascular risk factors at school age: the Generation R Study

Background:

Evidence suggests that low birth weight and fetal exposure to extreme maternal undernutrition is associated with cardiovascular disease in adulthood. Hyperemesis gravidarum, a clinical entity characterized by severe nausea and excess vomiting leading to a suboptimal maternal nutritional status during early pregnancy, is associated with an increased risk of adverse pregnancy outcomes. Several studies also showed that different measures related to hyperemesis gravidarum, such as maternal daily vomiting or severe weight loss, are associated with increased risks of adverse fetal pregnancy outcomes. Not much is known about long-term offspring consequences of maternal hyperemesis gravidarum and related measures during pregnancy. We examined the associations of maternal daily vomiting during early pregnancy, as a measure related to hyperemesis gravidarum, with childhood cardiovascular risk factors.

Methods:

In a population-based prospective cohort study from early pregnancy onwards among 4,769 mothers and their children in Rotterdam, the Netherlands, we measured childhood body mass index, total fat mass percentage, android/gynoid fat mass ratio, preperitoneal fat mass area, blood pressure, lipids, and insulin levels. We used multiple regression analyses to assess the associations of maternal vomiting during early pregnancy with childhood cardiovascular outcomes.

Results:

Compared with the children of mothers without daily vomiting during early pregnancy, the children of mothers with daily vomiting during early pregnancy had a higher childhood total body fat mass (difference 0.12 standard deviation score [SDS]; 95% confidence interval [CI] 0.03–0.20), android/gynoid fat mass ratio (difference 0.13 SDS; 95% CI 0.04–0.23), and preperitoneal fat mass area (difference 0.10 SDS; 95% CI 0–0.20). These associations were not explained by birth characteristics but partly explained by higher infant growth. Maternal daily vomiting during early pregnancy was not associated with childhood blood pressure, lipids, and insulin levels.

Conclusions:

Maternal daily vomiting during early pregnancy is associated with higher childhood total body fat mass and abdominal fat mass levels, but not with other cardiovascular risk factors. Further studies are needed to replicate these findings, to explore the underlying mechanisms and to assess the long-term consequences.

Severity of Nausea and Vomiting in Singleton and Twin Pregnancies in Relation to Fetal Sex: The Japan Environment and Children's Study (JECS)

Background

Some studies have indicated that female birth and multiple births were risk factors for nausea and vomiting during pregnancy (NVP). The results, however, were conflicting. Our study was conducted to evaluate the association of maternal NVP with fetal sex in singleton and twin pregnancies.

Methods

We used the data set from a birth cohort study, the Japan Environment and Children’s Study (JECS). In the self-administered questionnaire, participants were asked whether they experienced NVP prior to 12 gestational weeks. Main outcome measures were the presence of NVP and severity of NVP. We estimated the association of fetal sex and birth plurality with NVP using logistic regression analysis, followed by interaction analysis.

Results

Of 91,666 women, 75,828 (82.7%) experienced at least some symptoms of NVP and 10,159 (11.1%) experienced severe NVP. Women with female pregnancies and twin pregnancies had higher odds for the presence of NVP and severe NVP compared to women with male pregnancies and singleton pregnancies, respectively. Moreover, of mothers with twin pregnancies, higher odds for the presence of NVP and severe NVP were reported when one or both infants were female, compared to those in which both infants were male. There was no significant interaction between fetal sex and birth plurality.

Conclusions

Female sex birth and multiple births are risk factors for the presence of NVP, and especially for severe NVP without interaction. These findings suggest that a factor abundant in the female fetus associates with the severity of NVP.

Symptom severity in autism spectrum disorder is related to the frequency and severity of nausea and vomiting during pregnancy: a retrospective case-control study

Background

Nausea and vomiting during pregnancy (NVP) is thought to be caused by changes in maternal hormones during pregnancy. Differences in hormone exposure during prenatal life have been implicated in the causal pathways for some cases of autism spectrum disorder (ASD). However, no study has investigated whether the presence and severity of NVP may be related to symptom severity in offspring with ASD.

Methods

A large sample of children with ASD (227 males and 60 females, aged 2 to 18 years) received a clinical assessment, during which parents completed questionnaires regarding their child’s social (Social Responsiveness Scale, SRS) and communication (Children’s Communication Checklist–2nd edition, CCC-2) symptoms. Parents also reported on a 5-point scale the frequency and severity of NVPs during the pregnancy of the child being assessed: (1) no NVP during the pregnancy, (2) occasional nausea, but no vomiting, (3) daily nausea, but no vomiting, (4) occasional vomiting, with or without nausea, and (5) daily nausea and vomiting.

Results

Impairments in social responsiveness in offspring, as indexed by SRS total score, significantly increased as a function of the frequency and severity of their mothers’ NVP, as did the level of language difficulties as indexed by the Global Communication Composite of the CCC-2.

Conclusions

The strong, positive association between increasing frequency and severity of NVP and ASD severity in offspring provides further evidence that exposure to an atypical hormonal environment during prenatal life may affect neurodevelopment and contribute to the ASD phenotype. Given that the measure of NVP symptoms in the current study was based on retrospective recall, replication of this finding is required before strong conclusions can be drawn.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0223-7) contains supplementary material, which is available to authorized users.

Hyperemesis gravidarum and long-term mortality: a population-based cohort study

OBJECTIVE

To investigate whether exposure to hyperemesis gravidarum (HG) is associated with increased maternal long-term mortality.

DESIGN

Population-based cohort study.

SETTING

Medical Birth Registry of Norway (1967-2002) linked to the Cause of Death Registry.

POPULATION

Women in Norway with singleton births in the period 1967-2002, with and without HG. Women were followed until 2009 or death.

METHODS

Cox proportional hazard regression model was applied to estimate hazard ratios (HRs) with 95% confidence interval (CI).

MAIN OUTCOME MEASURES

The primary outcome was all-cause mortality during follow up. Secondary outcomes were cause-specific mortality (cardiovascular mortality, deaths due to cancer, external causes or mental and behavioural disorders).

RESULTS

Of 999 161 women with singleton births, 13 397 (1.3%) experienced HG. During a median follow up of 26 years (25 902 036 person-years), 43 470 women died (4.4%). Women exposed to HG had a lower risk of long-term all-cause mortality compared with women without HG (crude HR 0.82; 95% CI 0.75-0.90). When adjusting for confounders, this reduction was no longer significant (adjusted HR 0.92; 95% CI 0.84-1.01). Women exposed to HG had a similar risk of cardiovascular death as women not exposed (adjusted HR 1.04; 95% CI 0.83-1.29), but a lower long-term risk of death from cancer (adjusted HR 0.86; 95% CI 0.75-0.98).

CONCLUSION

In this large population-based cohort study, HG was not associated with an increased risk of long-term all-cause mortality. Women exposed to HG had no increase in mortality due to cardiovascular disease, but had a reduced risk of death from cancer.

TWEETABLE ABSTRACT

Population-based cohort study: Hyperemesis was not associated with an increased risk of long-term mortality.

Nausea and vomiting of pregnancy - What's new?

Nausea and vomiting of pregnancy (NVP) is one of the most common disorders of pregnancy. The symptoms occur predominantly during the first trimester, although in a subgroup of patients they can continue throughout the entire pregnancy and can affect the woman's quality of life. A small percentage of women develop a severe form of NVP called hyperemesis gravidarum (HG) that if left untreated may lead to significant maternal morbidity and adverse birth outcomes. Overall, the morbidity in pregnant women with NVP is significant, although it tends to be underestimated. The pathogenesis of NVP remains unclear, but there is consensus that the disorder is multifactorial and that various genetic, endocrine and infectious factors may be involved. The treatment of NVP can be challenging as the optimal targets for therapy are not known. Currently, the therapy used depends on the severity of the disorder and it is focused on improving the symptoms while minimizing risks to mother and fetus. Therapies range from dietary changes, pharmacologic treatment or hospitalization with intravenous fluid replacement and nutrition therapy. The aims of this review are 1) to provide an overview of NVP, 2) to present possible links between the most important factors associated with the pathogenesis of NVP and 3) to discuss the effectiveness and safety of the pharmacologic and non-pharmacologic options available to treat this disorder.

Hyperemesis gravidarum and placental dysfunction disorders

Background

Evidence about the consequence of hyperemesis gravidarum (HG) on pregnancy outcomes is still inconclusive. In this study, we evaluated if occurrence of hyperemesis gravidarum is associated with placental dysfunction disorders and neonatal outcomes.

Methods

A prospective cohort study was conducted in a maternal and child health primary care referral center, Budi Kemuliaan Hospital and its branch, in Jakarta, Indonesia. 2252 pregnant women visiting the hospital for regular antenatal care visits from July 2012 until October 2014 were included at their first clinic visit. For women without, with mild and with severe hyperemesis, placental dysfunction disorders (gestational hypertension, preeclampsia (PE), stillbirth, miscarriage), neonatal outcomes (birth weight, small for gestational age (SGA), low birth weight (LBW), Apgar score at 5 min, gestational age at delivery) and placental outcomes (placental weight and placental-weight-to-birth-weight ratio (PW/BW ratio)) were studied.

Results

Compared to newborns of women without hyperemesis, newborns of women with severe hyperemesis had a 172 g lower birth weight in adjusted analysis (95%CI -333.26; -10.18; p = 0.04). There were no statistically significant effects on placental dysfunction disorders or other neonatal outcome measures.

Conclusions

The results of our study suggest that hyperemesis gravidarum does not seem to induce placental dysfunction disorders, but does, if severe lead to lower birth weight.

Hyperemesis gravidarum, nutritional treatment by nasogastric tube feeding: a 10-year retrospective cohort study

OBJECTIVE

To investigate maternal and fetal outcome in hyperemesis gravidarum comparing enteral tube feeding of the mothers with other fluid/nutrition regimens.

DESIGN

Retrospective hospital-based cohort.

SETTING

University hospital, Norway.

SAMPLE

All 558 women treated for hyperemesis gravidarum 2002-2011; 273 received water/electrolytes intravenously, 177 received nutritional supplements by peripheral line, 107 received enteral feeding by gastroscopically positioned nasojejunal tube and 10 received total parenteral nutrition.

METHODS

Different fluid/nutritional groups were compared by chi-squared or non-parametric tests. The influence (odds ratio) of nutritional regimens on having small-for-gestational-age infants was evaluated by binary logistic regression.

MAIN OUTCOME MEASURES

Maternal weight gain during hospitalization and pregnancy, birthweight and gestational age at delivery.

RESULTS

Women receiving enteral nutrition had significantly greater weight loss on admission (median 5.0 kg) and at start of nutrition (5.5 kg) than the other treatment groups (4.0 kg) (p < 0.001). Enteral nutrition was administered for up to 41 days (median 5 days) during hospitalization, leading to 0.8 kg weight gain (95% CI 0.5-1.0, p = 0.005). The tube-fed women achieved similar weight gain during pregnancy and experienced similar incidence of preterm birth or small-for-gestational age compared with the other treatment groups. Women with <7 kg total weight gain had increased risk of birthweight <2500 g and small-for-gestational-age infants (odds ratio 3.68, 95% CI 1.89-7.18, p < 0.001). The nutritional regimen used was not an independent risk factor.

CONCLUSION

Compared with other fluid/nutrition regimens, enteral tube feeding for women affected by severe hyperemesis gravidarum is associated with adequate maternal weight gain and favorable pregnancy outcomes.