The protective effects of nausea and vomiting of pregnancy against adverse fetal outcome--a systematic review

Re-examining the adaptive function of nausea and vomiting in pregnancy

Nausea and vomiting in pregnancy (NVP) have been proposed to have a prophylactic function. In this review, I re-examine NVP from an evolutionary perspective in light of new research on NVP. First, current evidence suggests that the observed characteristics of NVP does not align well with a prophylactic function. Further, NVP is typically associated with high costs for pregnant women, while moderate-to-severe NVP is associated with increased risks of poorer foetal/birth outcomes. In contrast, mild NVP limited to early pregnancy may associate with improved foetal outcomes-indicating a potential evolutionary benefit. Second, researchers have recently identified growth differentiation factor 15 (GDF15) to cause NVP, with implications that low-levels of pre-conception GDF15 (associated with lower cellular stress/inflammation) may increase risks/symptoms of NVP. If so, NVP in contemporary post-industrialized populations may be more severe due to environmental mismatch, and the current symptomology of NVP in such populations should not be viewed as a typical experience of pregnancy.

Pregnancy outcomes by hyperemesis gravidarum severity and time of diagnosis: A retrospective cohort study

OBJECTIVE

With inconsistencies regarding the possible effect of hyperemesis gravidarum on the course of pregnancy, this research aimed to study the association between hyperemesis gravidarum and pregnancy outcomes, while also addressing the trimester of diagnosis and severity.

METHODS

A retrospective cohort study was performed, including all singleton deliveries of mothers from the largest health maintenance organization in the country, in a single tertiary hospital between 1991 and 2021. The incidence of adverse pregnancy outcomes was compared between pregnancies with and without hyperemesis gravidarum diagnosis. Multivariable generalized estimation equation binary models were used to study the association between maternal hyperemesis gravidarum, trimester of diagnosis and hyperemesis gravidarum severity and the studied outcomes.

RESULTS

The study population included 232 476 pregnancies, of which 3227 (1.4%) were complicated with hyperemesis gravidarum. Women with hyperemesis gravidarum were more likely to deliver preterm (adj. OR = 1.33, 95% CI: 1.18-1.50), a newborn with low birthweight (adj. OR = 1.52, 95% CI: 1.16-1.98, only if diagnosed in the second trimester), and to have a cesarean delivery (adj. OR = 1.20, 95% CI: 1.09-1.32). They were less likely to deliver small gestational age newborn (adj. OR = 0.82, 95% CI: 0.69-0.99) and their offspring to experience perinatal mortality (adj. OR = 0.54, 95% CI: 0.31-0.93, among mild cases only). A dose-response association was observed between preterm birth and hyperemesis gravidarum (adj. OR = 1.26; 95% CI: 1.11-1.44, for mild cases and adj. OR = 2.04; 95% CI: 1.31-3.19, for severe cases).

CONCLUSIONS

Hyperemesis gravidarum is associated with an increased risk for adverse pregnancy outcomes including mainly preterm delivery in a dose-response manner and when diagnosed during the second trimester.

The Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum (Green-top Guideline No. 69)

An objective and validated index of nausea and vomiting such as the Pregnancy-Unique Quantification of Emesis (PUQE) and HyperEmesis Level Prediction (HELP) tools can be used to classify the severity of NVP and HG. [Grade C] Ketonuria is not an indicator of dehydration and should not be used to assess severity. [Grade A] There are safety and efficacy data for first line antiemetics such as anti (H1) histamines, phenothiazines and doxylamine/pyridoxine (Xonvea®) and they should be prescribed initially when required for NVP and HG (Appendix III). [Grade A] There is evidence that ondansetron is safe and effective. Its use as a second line antiemetic should not be discouraged if first line antiemetics are ineffective. Women can be reassured regarding a very small increase in the absolute risk of orofacial clefting with ondansetron use in the first trimester, which should be balanced with the risks of poorly managed HG. [Grade B] Metoclopramide is safe and effective and can be used alone or in combination with other antiemetics. [Grade B] Because of the risk of extrapyramidal effects metoclopramide should be used as second-line therapy. Intravenous doses should be administered by slow bolus injection over at least 3 minutes to help minimise these. [Grade C] Women should be asked about previous adverse reactions to antiemetic therapies. If adverse reactions occur, there should be prompt cessation of the medications. [GPP] Normal saline (0.9% NaCl) with additional potassium chloride in each bag, with administration guided by daily monitoring of electrolytes, is the most appropriate intravenous hydration. [Grade C] Combinations of different drugs should be used in women who do not respond to a single antiemetic. Suggested antiemetics for UK use are given in Appendix III. [GPP] Thiamine supplementation (either oral 100 mg tds or intravenous as part of vitamin B complex (Pabrinex®)) should be given to all women admitted with vomiting, or severely reduced dietary intake, especially before administration of dextrose or parenteral nutrition. [Grade D] All therapeutic measures should have been tried before considering termination of pregnancy. [Grade C].

Maternal factors in the origin of cleft lip/cleft palate: A population-based case-control study

OBJECTIVES

Orofacial clefts are among the most common birth defects, with an estimated worldwide incidence of around 1.5-1.7 per 1000 live-born babies. The most frequent form of orofacial clefts is cleft lip with or without cleft palate (CL ± CP). The role of environmental factors in the development of clefts is unclear in most patients, thus the aim of this study was to estimate possible maternal risk factors in the origin of CL ± CP.

MATERIALS AND METHODS

1648 CL ± CP cases, 2654 matched controls and 57 231 population controls were evaluated from The Hungarian Case-Control Surveillance of Congenital Abnormalities. Maternal factors during the critical period in cases and controls were compared. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were estimated in a multivariable conditional logistic regression model.

RESULTS

Among socio-demographic data, we have found significant differences between maternal employment. The proportion of unskilled mothers (6.5%) were higher in the CL ± CP group than in controls (3.5%). Medically recorded maternal anaemia, excessive vomiting and threatened abortion were associated with a higher risk of CL ± CP. An elevated risk was also found in various acute illnesses such as influenza (OR: 2.4, 95% CI: 3.0-5.8), acute bronchitis (OR: 4.5, 95% CI: 1.6-12.6) and urinary tract infections (OR: 3.5, 95% CI: 2.0-6.0). Maternal migraine and essential hypertension occurred more frequently in the mothers of cases than in controls.

CONCLUSION

The findings of this study suggest that maternal diseases and lifestyle factors during the first trimester play a significant role in the development of CL ± CP.

Association of the Verbal Rating Scale-Measured Dysmenorrhea with Nausea and Vomiting in Pregnancy: A Retrospective Cohort Study

OBJECTIVES

Nausea and vomiting in pregnancy (NVP) is a common condition that reduces the quality of life by negatively affecting work and family life, physical and mental health, and economic well-being. However, its risk factors remain unclear. This study aimed to explore the association between NVP and verbal rating scale (VRS)-measured dysmenorrhea and to explore potential protective factors.

METHODS

This retrospective cohort study was conducted from June 2018 to December 2020 at Tongji Hospital in Wuhan. Information on baseline characteristics, pregnancy-related history, periconceptional micronutrient supplementation, and obstetric outcomes were collected. The severity of dysmenorrhea was assessed using VRS.

RESULTS

A total of 443 pregnant women were recruited and divided into the NVP group (n = 76) and the control group (n = 367). A significant association was observed between NVP and VRS-measured dysmenorrhea (c2=10.038, P = 0.007). After adjusting for covariates, the association between moderate/severe dysmenorrhea and NVP remained significant (OR 2.384; 95% CI 1.104-5.148, P = 0.004). First-trimester docosahexaenoic acid supplement (OR 0.443; 95% CI 0.205-0.960, P = 0.039) may be beneficial in reducing the risk of NVP.

CONCLUSIONS

Women with moderate to severe dysmenorrhea have a higher risk of experiencing NVP during the first trimester. Periconceptional docosahexaenoic acid supplementation may play a protective role.

The timing, duration, and severity of nausea and vomiting of pregnancy and adverse birth outcomes among controls without birth defects in the National Birth Defects Prevention Study

BACKGROUND

Nausea and vomiting of pregnancy (NVP) occurs in approximately 70% of pregnant people, with varying severity and duration. Treatments include pharmacologic and herbal/natural medications. The associations between NVP and birth outcomes, including preterm birth, small for gestational age (SGA), and low birth weight are inconclusive.

OBJECTIVE

To determine whether NVP and reported medications are associated with adverse birth outcomes.

METHODS

We used data from the population-based, multisite National Birth Defects Prevention Study (1997-2011) to evaluate whether self-reported NVP according to timing, duration, and severity or its specific treatments were associated with preterm birth, SGA, and low birth weight among controls without birth defects. Odds ratios (aOR) and 95% confidence intervals (CI) were adjusted for sociodemographic, reproductive, and medical factors. For any NVP, duration, treatment use, and severity score analyses, the comparison group was participants with no reported NVP. For timing analyses, the comparison group was women with no reported NVP in the same trimester of pregnancy.

RESULTS

Among 6018 participants, 4339 (72.1%) reported any NVP. Among those with NVP, moderate or severe symptoms were more common than mild symptoms. Any versus no NVP was not associated with any of the outcomes of interest. NVP in months 4-6 (aOR 1.21, 95% CI: 1.00, 1.47) and 7-9 (aOR 1.57, 95% CI: 1.22, 2.01) of pregnancy were associated with an increase in the risk of preterm birth. NVP lasting one trimester in duration was associated with decrease in risk of SGA (aOR: 0.74, 95% CI: 0.58, 0.95), and NVP present in every trimester of pregnancy had a 50% increase in risk of preterm birth (aOR: 1.50, 95% CI: 1.11, 2.05). For NVP in months 7-9 and preterm birth, ORs were elevated for moderate (aOR: 1.82, 95% CI: 1.26, 2.63), and severe (aOR: 1.53, 95% CI: 1.06, 2.19) symptoms. NVP was not significantly associated with low birth weight. Our analyses of medications were limited by small numbers, but none suggested increased risk of adverse outcomes associated with use of the medication.

CONCLUSION

Mild NVP and NVP limited to early pregnancy appear to have no effect or a small protective effect on birth outcomes. Long-lasting NVP, severe NVP, and NVP later in pregnancy may increase risk of preterm birth and SGA.

Evaluation of nausea and vomiting in the first trimester on the risk of adverse birth outcomes and the contribution of genetic polymorphisms: a pilot prospective study

PURPOSE

To evaluate the impact of Nausea and Vomiting in Pregnancy (NVP) on the risk of Preterm Birth (PTB) and Low Birth Weight (LBW), and explore the effect of genetic polymorphisms on the severity of NVP.

METHODS

A prospective study was conducted. Participants' experience of NVP prior to 12 gestational weeks were evaluated by a Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) scale. 11 Single Nucleotide Polymorphisms (SNPs) loci located in growth differentiation factor 15 (GDF15) and leucine-rich repeat containing 25 (LRRC25) gene of chr19p13.11 and intergenic region of chr4q12 were genotyped, which were implicated as genetic risk factors for NVP. Logistic regression models were applied to determine the effect of NVP in the first trimester on the risk of PTB and LBW, and genetic polymorphisms on the risk of NVP.

RESULTS

Among 413 pregnant women, the incidence of nausea and vomiting was 85.5% (n = 353) in the first trimester, including 38.7% (n = 160) mild vomiting, 42.6% (n = 176) moderate vomiting and 4.1% (n = 17) severe vomiting. 33 were PTB, 20 were LBW. Compared with pregnant women without NVP, women with mild, moderate or severe NVP in the first trimester were not associated with the risk of PTB and LBW. Besides, the polymorphisms of 11 SNPs loci were not associated with the risk of NVP.

CONCLUSIONS

Our study indicated that symptoms of nausea and vomiting in the first trimester were not significantly associated with PTB and LBW, and there were also no associations between GDF15 and LRRC25 polymorphisms and NVP.

Placenta-associated adverse pregnancy outcomes in women experiencing mild or severe hyperemesis gravidarum - a systematic review and meta-analysis

BACKGROUND

Nausea and vomiting in pregnancy (NVP) affects 50-80% of pregnant women and is correlated to the level of human chorionic gonadotropin (hCG). Hyperemesis gravidarum (HG) is a severe condition, with an incidence of 0.2-1.5%, characterized by consistent nausea, vomiting, weight loss and dehydration continuing after the second trimester.

AIM

The aim of this systematic review was to investigate a potential correlation between NVP or HG with adverse pregnancy outcomes and hCG levels.

METHOD

A systematic search in PubMed, Embase and CINAHL Complete was conducted. Studies on pregnant women with nausea in the first or second trimester, reporting either pregnancy outcomes or levels of hCG were included. The primary outcomes were preterm delivery (PTD), preeclampsia, miscarriage, and fetal growth restriction. Risk of bias was assessed using ROBINS-I. The overall certainty of evidence was assessed using GRADE.

RESULTS

The search resulted in 2023 potentially relevant studies; 23 were included. The evidence was uncertain for all outcomes, however women with HG had a tendency to have an increased risk for preeclampsia [odds ratio (OR) 1.18, 95% confidence of interval (CI) 1.03 to 1.35], PTD [OR 1.35, 95% CI 1.13 to 1.61], small for gestational age (SGA) [OR 1.24, 95% CI 1.13 to 1.35], and low birth weight (LBW) [OR 1.35, 95% CI 1.26 to 1.44]. Further, a higher fetal female/male ratio was observed [OR 1.36, 95% CI 1.15 to 1.60]. Meta-analyses were not performed for women with NVP; however, most of these studies indicated that women with NVP have a lower risk for PTD and LBW and a higher risk for SGA, and a higher fetal female/male ratio.

CONCLUSION

There may be an increased risk in women with HG and a decreased risk in women with NVP for adverse placenta-associated pregnancy outcomes, however the evidence is very uncertain.

TRIAL REGISTRATION

PROSPERO: CRD42021281218.

The association of nausea and vomiting of pregnancy, its treatments, and select birth defects: Findings from the National Birth Defect Prevention Study

BACKGROUND

Nausea and vomiting of pregnancy (NVP) occurs in approximately 70% of pregnant people. Treatments include pharmacologic and herbal/natural products. Research on the associations between NVP and its treatments and birth defects is limited.

METHODS

We used data from the case-control National Birth Defects Prevention Study (1997-2011) to examine whether first-trimester NVP or its specific treatments were associated with 37 major birth defects. Odds ratios (aOR) and 95% confidence intervals (CIs) were adjusted for sociodemographic and reproductive factors.

RESULTS

Mothers of 66.6% of 28,628 cases and 69.9% of 11,083 controls reported first-trimester NVP. Compared to no NVP, mothers with NVP had ≥10% reduction in risk of cardiac and noncardiac defects overall, and of 18 specific defects. Over-the-counter antiemetic use, compared to untreated NVP, was associated with ≥10% increase in risk for nine defect groups (heterotaxy, hypoplastic left heart syndrome [HLHS], aortic stenosis, cataracts, anophthalmos/microphthalmos, biliary atresia, transverse limb deficiency, omphalocele, and gastroschisis), whereas use of prescription antiemetics increased risk ≥10% for seven defect groups (tetralogy of Fallot, HLHS, spina bifida, anopthlamos/microphthalmos, cleft palate, craniosynostosis, and diaphragmatic hernia). We observed increased risks for promethazine and tetralogy of Fallot (aOR: 1.49, 95% CI: 1.05-2.10), promethazine and craniosynostosis (1.44, 1.08-1.92), ondansetron and cleft palate (1.66, 1.18-2.31), pyridoxine and heterotaxy (3.91, 1.49-10.27), and pyridoxine and cataracts (2.57, 1.12-5.88).

CONCLUSIONS

NVP does not increase risks of birth defects. Our findings that some treatments for NVP increase risk of specific birth defects should be investigated further before clinical recommendations are made.

Lack of catch-up in weight gain may intermediate between pregnancies with hyperemesis gravidarum and reduced fetal growth: the Japan Environment and Children’s Study

Background

Women with nausea and vomiting of pregnancy (NVP) have higher birth weight infants, while those with hyperemesis gravidarum, a severe manifestation of NVP, have lower birth weight infants. We aimed to investigate the associations between maternal weight loss (a consequence of hyperemesis gravidarum), NVP, and infant birth weight.

Methods

This study was a secondary analysis of a nationwide birth cohort in Japan. Singleton pregnancies delivered at 28–41 weeks of gestation were included in the analysis. Women were categorized based on their weight change in the 1^st trimester (as a proportion to their pre-pregnancy weight: >  + 3%, > 0 to + 3%, > -3 to 0%, > -5 to -3%, ≤ -5%) and severity of NVP (no nausea, only nausea, vomiting but able to eat, vomiting and unable to eat). The effects of weight change and severity of NVP on infant birth weight and small for gestational age (SGA) were assessed using regression models. We further examined how these effects could be modified by maternal weight gain up to the 2^nd trimester.

Results

Among 91,313 women, 5,196 (5.7%) lost ≥ 5% of their pre-pregnancy weight and 9,983 (10.9%) experienced vomiting and were unable to eat in the 1^st trimester. Women with weight loss ≥ 5% in the 1^st trimester had infants 66 (95% CI: 53, 78) g lighter and higher odds of SGA (aOR: 1.29; 95% CI: 1.14, 1.47) than women who gained > 3% during the same period. However, when adjusting for weight gain up to the 2^nd trimester, women with weight loss ≥ 5% in the 1^st trimester had infants 150 (95% CI: 135, 165) g heavier and lower odds of SGA (aOR: 0.39; 95% CI: 0.33, 0.46) than those who gained > 3% during the same period. In contrast, women with more severe NVP tended to have infants with larger birth weight and lower odds of SGA compared to women without NVP. These trends were strengthened when adjusting for weight gain up to the 2^nd trimester.

Conclusions

Our study suggests the possibility that reduced fetal growth in pregnancies with hyperemesis gravidarum may be caused by the lack of catch-up in gestational weight gain up to the 2^nd trimester.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04542-0.

Association of nausea and vomiting of pregnancy with infant growth in the first 24 months of life

PURPOSE

We aimed to investigate the association of maternal nausea and vomiting during pregnancy (NVP) with infant growth in the first 24 months of life and compare the effect of fetal gender.

METHODS

This prospective cohort study was conducted in Zhoushan Maternal and Child Health Hospital, Zhejiang, from 2011 to 2018. 1942 pairs of singleton newborns and their mothers were selected as participants. Main outcomes were gestational weight gain (GWG), birth outcomes (birthweight and gestational age) and infant growth [weight, height, weight/height-for-age Z score (WAZ/HAZ), the weight gain during childhood]. The associations of NVP with birth outcomes and infant growth at children's age of 1, 3, 6, 12, 18, and 24 months were analyzed by multivariable regression models.

RESULTS

Of the 1942 women, 1395 had NVP at first trimester (T1) and among them, 210 still experienced NVP at second trimester (T2). Compared with women without NVP, women experienced severe NVP at T1 were related with lower total GWG. Mild and moderate NVP at T1 were negatively associated with lower birthweight among women with male infants. Female infants exposed to maternal NVP at T1, especially for severe degree, were showed greater weight, WAZ, height, HAZ, and weight gain after 1 year old (at age of 12, 18, 24 months). No association between maternal NVP and infant growth was observed among male infants.

CONCLUSION

Exposure to NVP at T1 was, respectively, associated with lower GWG. Favorable influence of NVP at T1 on infant growth was observed among female offspring.

Hyperemesis gravidarum and neonatal outcomes: A systematic review of observational studies

Hyperemesis gravidarum (HG) is associated with adverse somatic and psychological effects. The impact of HG on neonatal outcomes is debatable given that disagreeing research results have appeared. The objective of this study was to systematically review, according to the PRISMA guidelines, and synthesize the available evidence from observational studies on the relationship between HG and neonatal outcomes. The PubMed, Scopus, and Science Direct databases were systematically reviewed, with the last search carried out in April 2020. The quality of the studies was estimated using the Newcastle-Ottawa Scale (NOS) for non-randomized studies. The databases search yielded 516 studies 15 of which (n = 112.372 HG cases) matched eligibility criteria while the majority of the studies were of moderate quality (n = 12). We observed heterogeneity among the studies regarding the definition of HG and characteristics of the samples. The results of this systematic review suggest that it is still uncertain whether HG has an adverse impact on neonatal outcomes, fact that requires more studies to be conducted.

Centered Partition Processes: Informative Priors for Clustering (with Discussion)

There is a very rich literature proposing Bayesian approaches for clustering starting with a prior probability distribution on partitions. Most approaches assume exchangeability, leading to simple representations in terms of Exchangeable Partition Probability Functions (EPPF). Gibbs-type priors encompass a broad class of such cases, including Dirichlet and Pitman-Yor processes. Even though there have been some proposals to relax the exchangeability assumption, allowing covariate-dependence and partial exchangeability, limited consideration has been given on how to include concrete prior knowledge on the partition. For example, we are motivated by an epidemiological application, in which we wish to cluster birth defects into groups and we have prior knowledge of an initial clustering provided by experts. As a general approach for including such prior knowledge, we propose a Centered Partition (CP) process that modifies the EPPF to favor partitions close to an initial one. Some properties of the CP prior are described, a general algorithm for posterior computation is developed, and we illustrate the methodology through simulation examples and an application to the motivating epidemiology study of birth defects.

Severity of nausea and vomiting in pregnancy and early childhood neurobehavioural outcomes: The Growing Up in Singapore Towards Healthy Outcomes study

BACKGROUND

Nausea and vomiting of pregnancy (NVP) affects 50 to 80 per cent of women. The existing literature has examined NVP from the perspective of the mother, and relatively less is known about offspring outcomes.

OBJECTIVES

To study the relationships of NVP with social-emotional, behavioural, and cognitive outcomes of the offspring in a multi-ethnic Asian cohort.

METHODS

In the Growing Up in Singapore Towards Healthy Outcomes prospective mother-offspring cohort study, mothers responded to a structured NVP questionnaire at 26-28 weeks' gestation (n = 1172) and participants with severe NVP were confirmed using medical records. Children underwent multiple neurodevelopmental assessments throughout childhood. We conducted multivariable regressions with post-estimation predictive margins to understand the associations of NVP with offspring neurobehavioural outcomes, which included 1-year Infant-Toddler Social and Emotional Assessment, 1.5-year Quantitative Checklist for Autism in Toddlers, 2-year Bayley Scales of Infant and Toddler Development, 2- and 4-year Child Behavior Checklist, and 4.5-year Kaufman Brief Intelligence Test. Analyses were adjusted for household income, birth variables, maternal mental health, and other relevant medical variables. Cohen's d effect sizes were calculated using standardised mean differences (μ_d ).

RESULTS

Mothers were categorised into no (n = 296, 25.3%), mild-moderate (n = 686, 58.5%), and severe NVP (n = 190, 16.2%), of whom 67 (5.7%) required admission. Compared to children of mothers who had no or mild-moderate NVP, children with exposure to severe NVP exhibited more externalising behaviours (μ_d 2.0, 95% CI 0.3, 3.6; Cohen's d = 0.33) and social communication difficulties before 2 years (μ_d 4.1, 95% Cl 0.1, 8.0; Cohen's d = 0.38), both externalising (μ_d 1.5, 95% CI 0.4, 2.6; Cohen's d = 0.43) and internalising behaviours at 2 years (μ_d 1.2, 95% CI 0.1, 2.2; Cohen's d = 0.35), and only internalising behaviours after 2 years (μ_d 1.1, 95% CI 0.4, 2.0; Cohen's d = 0.37).

CONCLUSIONS

Severe NVP is highly prevalent in this Asian cohort and may be adversely associated with multiple offspring neurobehavioural outcomes.

Trends in first-trimester nausea and vomiting of pregnancy and use of select treatments: Findings from the National Birth Defects Prevention Study

BACKGROUND

Although nausea and vomiting of pregnancy (NVP) is common, the secular and demographic trends of NVP and its treatments are not well-studied.

OBJECTIVES

To describe the prevalence and patterns of first-trimester NVP and selected treatments among controls in the National Birth Defects Prevention Study (NBDPS).

METHODS

National Birth Defects Prevention Study is a population-based case-control study of birth defects in the United States (1997-2011). We collected self-reported data about NVP and use of commonly reported pharmacological and herbal/natural treatments (ondansetron, promethazine, pyridoxine, metoclopramide, doxylamine succinate, ginger, phosphorated carbohydrate solution, and prochlorperazine) from mothers of non-malformed control infants. We estimated the prevalence of NVP and selected treatments and examined secular and demographic trends (education, race/ethnicity, and maternal age) for such use, adjusting for study centre.

RESULTS

Among 10 540 mothers of controls, 7393 women (70.1%) reported first-trimester NVP, and 12.2% of those used one or more of the commonly reported treatments. Specific treatment use varied after adjustment for study centre (ondansetron: 3.4%; promethazine: 4.2%; pyridoxine: 3.2%; metoclopramide: 0.7%; doxylamine succinate: 1.7%; ginger: 1.0%; phosphorated carbohydrate solution: 0.4%; and prochlorperazine: 0.3%). Treatment use increased for each agent over the study period. Women with more years of education reported more NVP and treatment use. White (72%), Hispanic (71%), and other race (73%) women reported more NVP than Black women (67%); White women used selected NVP treatments most frequently, and Black women used them more than Hispanic women. Though women aged 25-34 years reported more NVP (72%) than younger (69%) or older (67%) women, the frequency of medication use was similar among women aged 25-34 and ≥35, and lower among women aged <25 years.

CONCLUSIONS

National Birth Defects Prevention Study controls reported NVP at frequencies similar to those previously reported. Of note, we observed an increase in use of selected treatments over time, and variations in NVP and treatments by study site and demographic factors.

Update on the Management of Breast Cancer during Pregnancy

The diagnosis of breast cancer during pregnancy represents a challenging situation for the patient, her caregivers and physicians. Pregnancy adds complexity to oncological treatment planning, as many therapies can be potentially dangerous to the fetus. Therefore, a multidisciplinary approach is needed to offer a proper care for obtaining the best possible outcomes for the mother and the future child. Breast surgery is feasible throughout the pregnancy while radiotherapy should be postponed after delivery. Administration of chemotherapy is considered safe and can be given during the second and third trimesters, while it is contraindicated in the first trimester due to the high risk of fetal malformations. Endocrine therapy and targeted agents are not recommended during the whole pregnancy period; however, limited data are available on the use of the majority of new anticancer drugs in this context. The aim of the current review is to provide an update on the current state of art about the management of women diagnosed with breast cancer during pregnancy.

Polyunsaturated Fatty Acids and Their Metabolites in Hyperemesis Gravidarum

Polyunsaturated fatty acids (PUFAs) have been studied in relation to pregnancy. However, there is limited knowledge on PUFAs and their metabolites in relation to hyperemesis gravidarum (HG), a pregnancy complication associated with nutritional deficiencies and excessive vomiting. In order to survey the field, a systematic review of the literature was performed, which also included nausea and vomiting of pregnancy (NVP) due to its close relationship with HG. In the very few published studies found, the main subjects of the research concerned free fatty acids (four records), lipid profiles (three records), and bioactive lipids (one article about prostaglandin E₂ and one about endocannabinoids). The authors of these studies concluded that, although no cause-and-effect relationship can be established, HG is linked to increased sympathetic responsiveness, thermogenic activity and metabolic rate. In addition, NVP is linked to a metabolic perturbance (which lasts throughout pregnancy). The low number of retrieved records underlines the need for more research in the area of PUFAs and HG, especially with regard to the underlying mechanism for the detected effects, potentially involving growth differentiation factor 15 (GDF15) since evidence for GDF15 regulation of lipid metabolism and the role for GDF15 and its receptor in nausea and vomiting is emerging.

Assessment of otolith function using vestibular evoked myogenic potential in women during pregnancy

Introduction

More than 50% of pregnant women experience dizziness frequently in the first two gestational trimesters. During pregnancy, the changes in the metabolism of hormones are responsible for the ovarian cycle resulting in either peripheral or central vestibular alterations. The need for the study is to focus on the effect of changes during pregnancy on the vestibular evoked myogenic potential, an electrophysiological measure that investigates functions of the otolith structures.

Objectives

The aim is to investigate the vestibular evoked myogenic potential responses during the first trimester of pregnancy.

Methods

A total of 17 pregnant women and 17 non-pregnant women with age matched took part in this study. The cervical vestibular evoked myogenic potential were recorded from the ipsilateral sternocleridomastoid muscle and the ocular vestibular evoked myogenic potential were recorded from contralateral extraocular muscle in both groups.

Results

Peak to peak amplitude of cervical vestibular evoked myogenic potential and ocular vestibular evoked myogenic potential was found to be significantly reduced in the responses obtained from first-trimester pregnant women when compared to that of non-pregnant women.

Conclusions

Vestibular evoked myogenic potential tests exhibits a clinically significant reduced peak to peak amplitude in the first trimester of pregnancy, which indicates dysfunction in the otolith reflex pathway.

SOMANZ position paper on the management of nausea and vomiting in pregnancy and hyperemesis gravidarum

This is a brief summary of the Society of Obstetric Medicine of Australia and New Zealand (SOMANZ) evidence-based guideline for the management of nausea and vomiting of pregnancy (NVP) and hyperemesis gravidarum (HG). The full guideline and executive summary including auditable outcomes are freely available on the SOMANZ website [https://www.somanz.org/guidelines.asp]. The guideline includes a proposed SOMANZ definition of NVP and HG and evidence-based practical advice regarding the investigation and management of NVP, HG and associated conditions including thyroid dysfunction. A practical algorithm for assessment and management as well as an individual patient management plan and self-assessment tools are included.

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.

Flavored electronic cigarette use, preferences, and perceptions in pregnant mothers: A correspondence analysis approach

Use, preferences, and perceptions of flavored electronic cigarettes (e-cigarettes) were investigated in an ethnically diverse sample of pregnant mothers (N = 100; 50% smokers, M_age = 26; 66% low income; 65% minorities) via detailed interviews. Fruit and mint were the most commonly used flavors. Pregnant women endorsed increased use of fruit flavored e-cigarettes in preconception and pregnancy, greater preferences and intentions to use sweet flavors (fruit and candy), and lowest preferences for tobacco flavors. No differences in perceptions of general, pregnancy, or fetal-related health risks emerged across flavors. Latent factor mapping (biplots) based on correspondence analyses of contingency tables revealed clustering of more-preferred fruit and candy flavors versus least-preferred tobacco flavored e-cigarettes, with other sweet flavors-mint and alcohol-clustering more closely with fruit and candy flavors, and more pungent flavors-spice, coffee, chocolate-clustering near tobacco. Correspondence analysis also revealed uncorrelated clustering of preferences and harm perceptions, with intentions showing associations with both preferences and harm perceptions. Preference for fruit and mint flavored e-cigarettes and decreased harm perceptions significantly differentiated lifetime e-cigarette users from non-users. Results highlight preferences for fruit and mint flavored e-cigarettes during preconception and pregnancy, and links between preferences for fruit and mint flavors and lifetime use of e-cigarettes. These findings also highlight the utility of correspondence analysis for elucidating clustering of flavor perceptions and preferences for novel tobacco products.

First trimester ondansetron exposure and risk of structural birth defects

This study investigates risk of specific structural birth defects associated with ondansetron exposure during the first trimester in a large US commercially-insured population. Medical claims data were obtained from Truven Health Analytics for 864,083 mother-infant pairs from 2000 to 2014. Logistic regression was used to measure the association between first trimester exposure to ondansetron and risk of cardiac defects, orofacial clefts and other specific structural defects in offspring. First trimester exposure to ondansetron was associated with increased risk of cardiac (OR: 1.52 95% CI: 1.35-1.70) and orofacial cleft defects (OR: 1.32 95% CI: 0.76-2.28) in offspring compared to women with no antiemetic exposure during pregnancy. This analysis addresses limitations of prior studies including limited power, exposure misclassification, and generalizability to the US population. In a large, US population we found a statistically significant association between early pregnancy ondansetron exposure and specific structural birth defects in offspring.

Associations of vomiting and antiemetic use in pregnancy with levels of circulating GDF15 early in the second trimester: A nested case-control study

Background: Although nausea and vomiting are very common in pregnancy, their pathogenesis is poorly understood. We tested the hypothesis that circulating growth and differentiation factor 15 (GDF15) concentrations in early pregnancy, whose gene is implicated in hyperemesis gravidarum, are associated with nausea and vomiting. Methods: Blood samples for the measurement of GDF15 and human chorionic gonadotrophin (hCG) concentrations were obtained early in the second trimester (median 15.1 (interquartile range 14.4-15.7) weeks) of pregnancy from 791 women from the Cambridge Baby Growth Study, a prospective pregnancy and birth cohort. During each trimester participants completed a questionnaire which included questions about nausea, vomiting and antiemetic use. Associations with pre-pregnancy body mass indexes (BMI) were validated in 231 pregnant NIPTeR Study participants. Results: Circulating GDF15 concentrations were higher in women reporting vomiting in the second trimester than in women reporting no pregnancy nausea or vomiting: 11,581 (10,977-12,219) (n=175) vs. 10,593 (10,066-11,147) (n=193) pg/mL, p=0.02). In women who took antiemetic drugs during pregnancy (n=11) the GDF15 levels were also raised 13,157 (10,558-16,394) pg/mL (p =0.04). Serum GFD15 concentrations were strongly positively correlated with hCG levels but were inversely correlated with maternal BMIs, a finding replicated in the NIPTeR Study. Conclusions: Week 15 serum GDF15 concentrations are positively associated with second trimester vomiting and maternal antiemetic use in pregnancy. Given GDF15's site of action in the chemoreceptor trigger zone of the brainstem and its genetic associations with hyperemesis gravidarum, these data support the concept that GDF15 may be playing a pathogenic role in pregnancy-associated vomiting.

Nausea and vomiting during pregnancy associated with lower incidence of preterm births: the Japan Environment and Children's Study (JECS)

Background

Nausea and vomiting during pregnancy (NVP) is considered to be associated with favorable fetal outcomes, such as a decreased risk for spontaneous abortion. However, the relationship between NVP and preterm births remains unknown. This study was conducted to evaluate the association between NVP and the risk of preterm births.

Methods

The dataset of a birth cohort study, the Japan Environment and Children’s Study (JECS), was retrospectively reviewed. Participants’ experience of NVP prior to 12 gestational weeks were evaluated by a questionnaire administered from 22 weeks of pregnancy to 1 month before delivery. NVP responses were elicited against four choices based on which the study population was divided into four subcohorts. Preterm birth was the main study outcome. Logistic regression analysis was used to quantify an association between NVP and risk of preterm birth.

Results

Of 96,056 women, 79,460 (82.7%) experienced some symptoms of NVP and 10,518 (10.9%) experienced severe NVP. Compared to those who did not experience NVP, women with severe NVP had lower odds for preterm birth [adjusted odds ratio (aOR) 0.84, 95% confidence interval (95% CI) 0.74–0.95]. An even lower OR was found among very preterm birth and extremely preterm birth (aOR 0.44, 95% CI 0.29–0.65).

Conclusion

An inverse association exists between NVP and preterm births, especially, very preterm births and extremely preterm births.

Hyperemesis gravidarum-Is it a cause of abnormal fetal brain development?

Hyperemesis gravidarum (HG) is characterized by severe gestational nausea and vomiting, leading to dehydration, electrolyte imbalance and nutritional deficits. HG adversely affects the health and wellbeing of the woman. However, the detrimental impact of HG on fetal brain development has not been addressed. We evaluate herein the emerging evidence suggesting that HG interferes with human brain development, and discuss putative mechanisms. Evidence emerges from prospective developmental studies in offspring exposed in utero to HG, from studies of pregnancy outcome after in utero exposure to famine, as well as evidence on specific nutritional deficiencies affecting fetal brain development.

Vomiting in pregnancy is associated with a higher risk of low birth weight: a cohort study

BACKGROUND

Low birth weight has important short- and long-term health implications. Previously it has been shown that pregnancies affected by hyperemesis gravidarum in the mother are at higher risk of having low birth weight offspring. In this study we tested whether such risks are also evident with less severe nausea and vomiting in pregnancy.

METHODS

One thousand two hundred thirty-eight women in the prospective Cambridge Baby Growth Study filled in pregnancy questionnaires which included questions relating to adverse effects of pregnancy and drugs taken during that time. Ordinal logistic regression models, adjusted for parity, ethnicity, marital and smoking status were used to relate the risk of giving birth to low birth weight (< 2.5 kg) babies to nausea and/or vomiting in pregnancy that were not treated with anti-emetics and did not report suffering from hyperemesis gravidarum.

RESULTS

Only three women in the cohort reported having had hyperemesis gravidarum although a further 17 women reported taking anti-emetics during pregnancy. Of those 1218 women who did not take anti-emetics 286 (23.5%) did not experience nausea or vomiting, 467 (38.3%) experienced nausea but not vomiting and 465 experienced vomiting (38.2%). Vomiting during pregnancy was associated with higher risk of having a low birth weight baby (odds ratio 3.5 (1.2, 10.8), p = 0.03). The risk associated with vomiting was found in the first (p = 0.01) and second (p = 0.01) trimesters but not the third (p = 1.0). The higher risk was not evident in those women who only experienced nausea (odds ratio 1.0 (0.3, 4.0), p = 1.0).

CONCLUSIONS

Vomiting in early pregnancy, even when not perceived to be sufficiently severe to merit treatment, is associated with a higher risk of delivering a low birth weight baby. Early pregnancy vomiting might therefore be usable as a marker of higher risk of low birth weight in pregnancy. This may be of benefit in situations where routine ultrasound is not available to distinguish prematurity from fetal growth restriction, so low birth weight is used as an alternative.

Evaluation of nausea and vomiting in pregnancy using the Pregnancy-Unique Quantification of Emesis and Nausea scale in Korea

Objective

Severity of nausea and vomiting of pregnancy (NVP) is associated with adverse pregnancy outcomes and poorer quality of life (QOL). The aim of this study was to evaluate the severity of NVP and maternal well-being status using the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) scale in a Korean population.

Methods

A total of 527 pregnant women who were receiving prenatal care at 4 hospitals were asked to participate in the study between January 2015 and June 2015. The severity of NVP was evaluated by the PUQE scale and maternal well-being status was evaluated using the visual analogue scale (VAS). Statistical analyses were performed to determine the risk factors associated with NVP and the associations between the severity of NVP and QOL.

Results

Among the 472 eligible pregnant women, 381 (80.7%) were suffering from NVP during pregnancy. No significant differences (P>0.05) were observed in any of the variables between the 2 study groups, with the exception of smoking, alcohol consumption, and history of NVP. NVP history was found to be the most powerful risk factor (adjusted odds ratio, 11.6; 95% confidence interval, 4.7-28.7). The correlation coefficient (r) between the VAS scores of maternal well-being status and PUQE severity was -0.25 (r²=0.062; P<0.001).

Conclusion

In this study, an explicit decline in maternal well-being status was observed according to severity of NVP. The PUQE scale may be of help to clinicians, healthcare providers, and researchers because of its simplicity and usefulness as a tool for NVP evaluation.

The Risk of Adverse Pregnancy Outcome After First Trimester Exposure to H1 Antihistamines: A Systematic Review and Meta-Analysis

INTRODUCTION

H1 antihistamines are used for the treatment of nausea and vomiting during pregnancy as well as the symptomatic relief of asthma, urticaria, allergy, and the common cold. Although they are overall felt to be safe during pregnancy, recently several studies have challenged this assumption, as millions of women are exposed to them in the first trimester.

METHODS

Following the guidelines of PRISMA, a systematic review was performed to retrieve all published articles involving H1-antihistamine exposure during pregnancy. Electronic databases including PubMed and EMBASE were searched for possibly relevant articles published in any language up to December 2015.

RESULTS

After removing duplicate publications, and excluding animal studies and studies on drug effectiveness, 342 articles were reviewed in detail and 37 studies fulfilled the inclusion criteria for the meta-analysis. In cohort studies, the risk of major malformation in the offspring of women exposed to H1 antihistamines was not higher than that of the control population (OR 1.07; 95% CI 0.98-1.16). The Q-statistic for heterogeneity of effects was not significant (p > 0.05, I ² < 25%) and there was no evidence of publication bias. Similar results were achieved with case-control studies (OR 1.05; 95% CI 0.90-1.23). Similarly, H1 antihistamines were not associated with more spontaneous abortions (OR 1.00; 95% CI 0.83-1.20), prematurity (OR 0.96; 95% CI 0.76-1.20), stillbirth (OR 1.23; 95% CI 0.48-3.18) or low birth weight (OR 1.20; 95% CI 0.63-2.29).

CONCLUSIONS

Based on our meta-analyses, which included a large number of studies, H1 antihistamines are not associated with an increased risk of major malformation or other adverse fetal outcomes. This study provides important information to both pregnant women and their healthcare providers regarding the safety and risk of H1 antihistamine use during this sensitive time.

Association between vomiting in the first trimester and preterm birth: a retrospective birth cohort study in Wuhan, China

OBJECTIVE

Although vomiting in the first trimester has been reported to be associated with preterm birth (PTB), findings supporting this association remain inconsistent. Our aim was to assess the association between vomiting and PTB, as well as evaluate if the association is modified by pre-pregnancy body mass index (BMI).

DESIGN

A retrospective cohort study.

SETTING

Wuhan, a central city of China.

PARTICIPANTS

A total of 317 463 pregnant women who had a live, singleton newborn from 1 January 2010 to 23 May 2016 were enrolled in our study.

MAIN OUTCOME MEASURE

PTB was defined as gestational age <37 gestational weeks. Gestational age was calculated using reports from mothers based on the first day of their last menstrual period. An ultrasound was routinely used to determine gestational age before 12 gestational weeks.

RESULTS

Of the 317 463 pregnant women, 29.88% (94 857) experienced vomiting in the first trimester and 5.00% (15 889) experienced a PTB. Vomiting in the first trimester increased the risk for PTB and the multivariable adjusted OR was 1.05 (95% CI 1.02 to 1.09). In the stratified analyses, the association of vomiting in the first trimester was significant among underweight women (adjusted OR=1.08, 95% CI 1.04 to 1.17) and normal pre-pregnancy BMI women (adjusted OR=1.06, 95% CI 1.02 to 1.11), but not in overweight women (adjusted OR=1.01, 95% CI 0.90 to 1.14) and obese women (adjusted OR=0.93, 95% CI 0.73 to 1.19).

CONCLUSIONS

Our study indicates that vomiting in the first trimester was associated with PTB. Additionally, women with underweight and normal pre-pregnancy BMI who experienced vomiting are more likely to have a PTB.

Stimulation of Thyroid Function by Human Chorionic Gonadotropin During Pregnancy: A Risk Factor for Thyroid Disease and a Mechanism for Known Risk Factors

BACKGROUND

Thyroid autoimmunity is a major risk factor for gestational thyroid disease, and recently various other risk factors have been identified, including maternal age, body mass index (BMI) and parity. Human chorionic gonadotropin (hCG) is an important determinant of gestational thyroid function, yet it is unknown to what extent differences in hCG concentration affect the risk for thyroid disease. We have recently shown that thyroperoxidase antibody positivity impairs the thyroidal response to hCG stimulation, which may suggest that this is a mechanism through which thyroid autoimmunity acts as a risk factor for thyroid disease.

OBJECTIVE

The purpose of this study is to determine whether hCG is a risk factor for thyroid disease entities and whether recently identified risk factors for thyroid disease may influence the thyroidal response to hCG stimulation.

METHODS

Human chorionic gonadotropin, thyrotropin (TSH), and free thyroxine (FT4) were measured in 5435 pregnant women participating in a prospective cohort. The association of hCG with thyroid disease entities, and the association of known risk factors with thyroidal response to hCG stimulation were studied using multivariable linear regression models.

RESULTS

Higher hCG concentrations were associated with a higher risk of subclinical and overt hyperthyroidism. Lower hCG concentrations were associated with a higher risk of hypothyroxinemia. In contrast, hCG concentrations were not associated with subclinical hypothyroidism. Further analyses showed that in women with hypothyroxinemia, high hCG concentrations still suppressed TSH. However, in women with subclinical hypothyroidism, high hCG concentrations were not associated with higher FT4. Higher BMI, male fetal sex, and maternal parity >2 were associated with a lower thyroidal response to hCG stimulation.

CONCLUSIONS

Human chorionic gonadotropin is associated with the risk of (subclinical) hyperthyroidism and hypothyroxinemia, but not with the risk of (subclinical) hypothyroidism. Women with hypothyroxinemia have a normal response to thyroidal stimulation by hCG, but this was abnormal in women with subclinical hypothyroidism. Known risk factors for thyroid dysfunction (BMI and parity), and also male fetal sex, are associated with a lower thyroidal response to hCG stimulation.

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.

The Risk of Preeclampsia According to High Thyroid Function in Pregnancy Differs by hCG Concentration

CONTEXT

During pregnancy, there is an increased demand for thyroid hormone. The pregnancy hormone human chorionic gonadotropin (hCG) is an important physiological stimulator of thyroid function. Already high-normal maternal free T₄ concentrations are associated with a higher risk of preeclampsia.

OBJECTIVE

The objective of the investigation was to study our hypothesis that hCG concentrations can distinguish a physiological form of high thyroid function from a more pathological form of high thyroid function and that the risk of preeclampsia would differ accordingly.

DESIGN

TSH, free T₄, hCG, or thyroperoxidase antibody concentrations were determined in pregnant women participating in a population-based prospective cohort study.

SETTING

The study was conducted in the general community.

PARTICIPANTS

A nonselected sample of 5146 pregnant women participated in the study.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE(S)

Preeclampsia was measured.

RESULTS

Women with high hCG-associated high thyroid function did not have a higher risk of preeclampsia than women with normal thyroid function. In contrast, women with low hCG and high thyroid function had a 3.4- to 11.1-fold higher risk of preeclampsia. These risk estimates were amplified in women with a high body mass index. Women with a low hCG and suppressed TSH (<0.10 mU/L) had a 3.2- to 8.9-fold higher risk of preeclampsia. hCG was not associated with preeclampsia, and results remained similar after exclusion of thyroperoxidase antibody-positive women.

CONCLUSION

This study suggests that, in contrast to women with a high hCG associated high thyroid function, women with low hCG and high thyroid function during pregnancy are at a higher risk of developing preeclampsia. The additional measurement of hCG may therefore help to distinguish a more pathological form of high thyroid function and women at a high risk of preeclampsia.

Signs and Symptoms of Early Pregnancy Loss

Approximately one-third of pregnancies end in loss; however, the natural history of early pregnancy loss, including signs and symptoms preceding loss, has yet to be fully described and its underlying mechanisms fully understood. We searched PubMed/MEDLINE and Embase to identify articles with prospective ascertainment of signs and symptoms, including vaginal bleeding, nausea, and vomiting, of pregnancy loss < 20 weeks gestation in spontaneous conceptions to ascertain existing literature on symptomatology of pregnancy loss. Two preconception and 16 pregnancy cohort studies that ascertained information on bleeding and/or nausea/vomiting prior to pregnancy loss ascertainment were included. Data from these studies indicated increased risk of loss with vaginal bleeding and decreased risk of loss with nausea/vomiting, though these studies were mostly comprised of pregnancies surviving into late first trimester. While such associations are biologically plausible, these study designs are subject to bias, given recruitment of women at later gestational ages and reliance on women presenting to care. Reporting symptoms to clinicians and over long periods may introduce reporting error. Data gaps remain regarding (1) relationships between signs and symptoms and losses occurring very early, prior to care entry; (2) empirical testing of whether relationships between signs and symptoms and loss differ across gestational age; (3) whether similar relationships between signs and symptoms and loss are observed in populations using assisted reproductive technologies; (4) the patterning of multiple signs and symptoms in relation to loss; and (5) how hormonal and physiologic adaptions to early pregnancy relate to symptomatology and pregnancy loss.

Nausea and Vomiting During Pregnancy is Highly Heritable

Nausea and vomiting during pregnancy (NVP) affects about 70 % of all expectant mothers and commonly impacts their physical health and psychosocial functioning. The aim of this study was to estimate the heritability of the presence, duration and severity of NVP. The sample consisted of 1723 women (M age = 41.78, SD = 11.67) including twins in both complete and incomplete pairs and their sisters from two cohorts participating in the NVP Genetics Consortium. The sample comprised 159 monozygotic and 140 dizygotic complete twin pairs, and 69 twin-sister pairs. We applied an extended twin design using OpenMx and Mx for secondary analysis. Individual differences in NVP were best explained by additive genetic and unique environmental effects. Heritability estimates were 73 % (95 % CIs = 57-84 %) for presence, 51 % (95 % CIs = 36-63 %) for duration and 53 % (95 % CIs = 38-65 %) for severity of NVP. The genetic correlation between duration and severity was almost perfect. Our results show that genes play an important role in different aspects of NVP and justify the importance of searching for genetic variants.