Hyperemesis gravidarum in the Medical Birth Registry of Norway - a validity study

Hospital Outcomes in Medical Patients With Alcohol-Related and Non-Alcohol-Related Wernicke Encephalopathy

OBJECTIVE

To conduct a nationwide retrospective cohort study to assess trends and hospitalization-associated outcomes in patients with Wernicke encephalopathy.

PATIENTS AND METHODS

In this nationwide retrospective cohort study, we used in-hospital claims data of patients hospitalized with Wernicke encephalopathy in Switzerland from January 1, 2012, to December 31, 2020. We estimated incidence rates per 100,000 person-years among the overall Swiss population stratified by alcohol and non-alcohol-induced Wernicke encephalopathy. The primary outcome was all-cause in-hospital mortality. Secondary outcomes included progression to Korsakoff syndrome and 1-year hospital readmission. We estimated odds ratios (ORs) for binary outcomes.

RESULTS

It was found that 4098 of 4393 hospitalizations (93.3%) for Wernicke encephalopathy during the 8-year study were alcohol-related. Incidence rates for hospitalizations were 14-fold higher in alcohol-related compared with non-alcohol-related Wernicke encephalopathy (5.43 vs 0.39 per 100,000 person-years). The risk for in-hospital mortality was significantly lower in patients with alcohol-related vs non-alcohol-related Wernicke encephalopathy (3.2% vs 8.5%; adjusted OR, 0.38; 95% CI, 0.23 to 0.62). Patients with alcohol-related Wernicke encephalopathy had higher risk for development of Korsakoff syndrome (16.9% vs 1.7%; adjusted OR, 10.64; 95% CI, 4.37 to 25.92) and 1-year hospital readmission (31.6% vs 18.7%; adjusted OR, 1.4; 95% CI, 1.04 to 1.88).

CONCLUSION

In this Swiss nationwide cohort study, Wernicke encephalopathy was a rare but serious cause for hospitalization and mainly alcohol-related. Patients with alcohol-related Wernicke encephalopathy had lower risks of in-hospital mortality but were more likely to develop Korsakoff syndrome and be readmitted to the hospital.

Depression, anxiety, and post-traumatic stress disorder symptoms after hyperemesis gravidarum: a prospective cohort study

OBJECTIVE

To determine the prevalence of depression, anxiety, and posttraumatic stress disorder (PTSD) years after hyperemesis gravidarum (HG) and its association with HG severity.

MATERIAL AND METHODS

This prospective cohort study consisted of a follow-up of 215 women admitted for HG, who were eligible to participate in a randomized controlled trial and either declined or agreed to be randomized between 2013 and 2016 in 19 hospitals in the Netherlands. Participants completed the Hospital Anxiety and Depression Scale (HADS) six weeks postpartum and during follow-up and the PTSD checklist for DSM-5 (PCL-5) during follow-up. An anxiety or depression score ≥8 is indicative of an anxiety or depression disorder and a PCL-5 ≥ 31 indicative of PTSD. Measures of HG severity were symptom severity (PUQE-24: Pregnancy Unique Quantification of Emesis), weight change, duration of admissions, readmissions, and admissions after the first trimester.

RESULTS

About 54/215 participants completed the HADS six weeks postpartum and 73/215 participants completed the follow-up questionnaire, on average 4.5 years later. Six weeks postpartum, 13 participants (24.1%) had an anxiety score ≥8 and 11 participants (20.4%) a depression score ≥8. During follow-up, 29 participants (39.7%) had an anxiety score ≥8, 20 participants (27.4%) a depression score ≥8, and 16 participants (21.9%) a PCL-5 ≥ 31.Multivariable logistic regression analysis showed that for every additional point of the mean PUQE-24 three weeks after inclusion, the likelihood of having an anxiety score ≥8 and PCL-5 ≥ 31 at follow-up increased with OR 1.41 (95% CI: 1.10;1.79) and OR 1.49 (95% CI: 1.06;2.10) respectively.

CONCLUSION

Depression, anxiety, and PTSD symptoms are common years after HG occurred.

Long-term health outcomes of children born to mothers with hyperemesis gravidarum: a systematic review and meta-analysis

OBJECTIVE

Hyperemesis gravidarum is characterized by severe nausea and vomiting in pregnancy, frequently resulting in severe maternal nutritional deficiency. Maternal undernutrition is associated with adverse offspring health outcomes. Whether hyperemesis gravidarum permanently affects offspring health remains unclear. This review aimed to evaluate the effects of maternal hyperemesis gravidarum on offspring health.

DATA SOURCES

MEDLINE and Embase were searched from inception to September 6, 2021.

STUDY ELIGIBILITY CRITERIA

Studies reporting on health at any age beyond the perinatal period of children born to mothers with hyperemesis gravidarum were included.

METHODS

Two reviewers independently selected studies and extracted data. The Newcastle-Ottawa Quality Assessment Scale was used to assess risk of bias. We conducted a narrative synthesis and meta-analysis where possible. In meta-analyses with high heterogeneity (I²>75%), we did not provide a pooled odds ratio.

RESULTS

Nineteen studies were included in this systematic review (n=1,814,785 offspring). Meta-analysis (n=619, 2 studies: 1 among adolescents and 1 among adults) showed that hyperemesis gravidarum was associated with anxiety disorder (odds ratio, 1.74; 95% confidence interval, 1.04-2.91; I², 0%) and sleep problems in offspring (odds ratio, 2.94; 95% confidence interval, 1.25-6.93; I², 0%). Hyperemesis gravidarum was associated with testicular cancer in male offspring aged up to 40 years on meta-analysis (5 studies, n=20,930 offspring), although heterogeneity was observed on the basis of a wide 95% prediction interval (odds ratio, 1.60; 95% confidence interval, 1.07-2.39; I², 0%; 95% prediction interval, 0.83-3.08). All 6 studies reporting on attention deficit (hyperactivity) disorder and autism spectrum disorder reported an increase among children of mothers with hyperemesis gravidarum in comparison with children of unaffected mothers. Meta-analysis showed high heterogeneity, precluding us from reporting a pooled odds ratio. Most studies reporting on cognitive and motor problems found an increase among hyperemesis gravidarum-exposed children. One study investigated brain structure and found smaller cortical volumes and areas among children from hyperemesis gravidarum-affected pregnancies than among those from unaffected pregnancies. Studies evaluating anthropometry and cardiometabolic disease risk of hyperemesis gravidarum-exposed children had inconsistent findings.

CONCLUSION

Our systematic review showed that maternal hyperemesis gravidarum is associated with small increases in adverse health outcomes among children, including neurodevelopmental disorders, mental health disorders, and possibly testicular cancer, although evidence is based on few studies of low quality.

Recurrence, postponing pregnancy, and termination rates after hyperemesis gravidarum: Follow up of the MOTHER study

Introduction

Hyperemesis gravidarum (HG) complicates 1% of pregnancies and has a major impact on maternal quality of life and well‐being. We know very little about HG’s long‐term impact after an affected pregnancy, including recurrence rates in future pregnancies, which is essential information for women considering subsequent pregnancies. In this study, we aimed to prospectively measure the recurrence rate of HG and the number of postponed and terminated subsequent pregnancies due to HG. We also aimed to evaluate if there were predictive factors that could identify women at increased risk for HG recurrence, and postponing and terminating subsequent pregnancies.

Material and methods

We conducted a prospective cohort study. A total of 215 women admitted for HG to public hospitals in the Netherlands were enrolled in the original MOTHER randomized controlled trial and associated observational cohort. Seventy‐three women were included in this follow‐up study. Data were collected through an online questionnaire. Recurrent HG was defined as vomiting symptoms accompanied by any of the following: multiple medication use, weight loss, admission, tube feeding or if nausea and vomiting symptoms were severe enough to affect life and/or work. Outcome measures were recurrence, postponing, and termination rates due to HG. Univariable logistic regression analysis was used to identify predictive factors associated with HG recurrence, and postponing and terminating subsequent pregnancies.

Results

Thirty‐five women (48%) became pregnant again of whom 40% had postponed their pregnancy due to HG. HG recurred in 89% of pregnancies. One woman terminated and eight women (23%) considered terminating their pregnancy because of recurrent HG. Twenty‐four out of 38 women did not get pregnant again because of HG in the past. Univariable logistic regression analysis identifying possible predictive factors found that having a western background was associated with having weight loss due to recurrent HG in subsequent pregnancies (odds ratio 12.9, 95% CI 1.3–130.5, p = 0.03).

Conclusions

High rates of HG recurrence and a high number of postponed pregnancies due to HG were observed. Women can be informed of a high chance of recurrence to enable informed family planning.

Validation of Assisted Reproductive Technology in the Medical Birth Registry of Norway Versus the Norwegian Prescription Database

BACKGROUND

Increasing attention has been given to the long-term effects of assisted reproductive technology (ART). This study assessed the validity and completeness of ART as registered in the Medical Birth Registry of Norway (MBRN) using drug prescription data from the Norwegian Prescription Database (NorPD) as reference.

METHODS

In this nationwide registry validation study, we included all pregnancies recorded in the MBRN between 2005 and 2017. We estimated sensitivity, specificity, and positive and negative predictive value (PPV and NPV) of the MBRN, using data from the NorPD as reference. We obtained the total percentage of ART pregnancies that could be identified (completeness) from both registries using the capture-recapture method. We analyzed subgroups by maternal age, gestational length, mode of ART treatment, health region, and mode of registration of ART (ART institution or birth notification form).

RESULTS

Twenty-three thousand seven hundred eighteen of a total 765,789 pregnancies were registered as ART pregnancies through the MBRN and 20,807 as ART pregnancies through the NorPD. The sensitivity of the MBRN was 85.1% (95% confidence interval [CI] = 84.7, 85.6) and the PPV was 74.7% (74.1-75.2). Sensitivity declined with increasing maternal age: 71.5% (69.4-73.7) in the age group 40-44 years, and 40.7% (22.2-59.3) in the ages above 45 years. Completeness when combining data was 96.2% (96.0-96.5).

CONCLUSIONS

Our analysis shows that, when identifying women pregnant through ART, NorPD data complemented MBRN data to obtain a more complete count of all women giving birth after ART in Norway.

Low risk pregnancies after a cesarean section: Determinants of trial of labor and its failure

Introduction

In pregnancies after a previous cesarean section (CS), a planned repeat CS delivery has been associated with excess risk of adverse outcome. However, also the alternative, a trial of labor after CS (TOLAC), has been associated with excess risks. A TOLAC failure, involving a non-planned CS, carries the highest risk of adverse outcome and a vaginal delivery the lowest. Thus, the decision regarding delivery mode is pivotal in clinical handling of these pregnancies. However, even with a high TOLAC rate, as seen in Norway, repeat CSs are regularly performed for no apparent medical reason. The objective of the present study was to assess to which extent demographic, socioeconomic, and health system factors are determinants of TOLAC and TOLAC failure in low risk pregnancies, and whether any effects observed changed with time.

Materials and methods

The study group comprised 24 645 second deliveries (1989–2014) after a first delivery CS. Thus, none of the women had prior vaginal deliveries or more than one CS. Included pregnancies were low risk, cephalic, single, and had gestational age ≥ 37 weeks. Data were obtained from the Medical Birth Registry of Norway (MBRN). The exposure variables were (second delivery) maternal age, length of maternal education, maternal country of origin, size of the delivery unit, health region (South-East, West, Mid, North), and maternal county of residence. The outcomes were TOLAC and TOLAC failure, as rates (%), relative risk (RR) and relative risk adjusted (ARR). Changes in determinant effects over time were assessed by comparing rates in two periods, 1989–2002 vs 2003–2014, and including these periods in an interaction model.

Results

The TOLAC rate was 74.9%, with a TOLAC failure rate of 16.2%, resulting in a vaginal birth rate of 62.8%. Low TOLAC rates were observed at high maternal age and in women from East Asia or Latin America. High TOLAC failure rates were observed at high maternal age, in women with less than 11 years of education, and in women of non-western origin. The effects of health system factors, i.e. delivery unit size and administrative region were considerable, on both TOLAC and TOLAC failure. The effects of several determinants changed significantly (P < 0.05) from 1989–2002 to 2003–2014: The association between non-TOLAC and maternal age > 39 years became weaker, the association between short education and TOLAC failure became stronger, and the association between TOLAC failure and small size of delivery unit became stronger.

Conclusion

Low maternal age, high education, and western country of origin were associated with high TOLAC rates, and low TOLAC failure rates. Maternity unit characteristics (size and region) contributed with effects on the same level as individual determinants studied. Temporal changes were observed in determinant effects.

The chance of recurrence of hyperemesis gravidarum: A systematic review

Around 1 % of pregnancies develop Hyperemesis Gravidarum (HG), causing high physical and psychological morbidity. Reports on HG recurrence rate in subsequent pregnancies vary widely. An accurate rate of recurrence is needed for informed reproductive decision making. Our objective is to systematically review and aggregate reported rates for HG subsequent to index pregnancies affected by HG. We searched databases from inception as per the protocol registered on PROSPERO. No language restrictions were applied. Inclusion was not restricted based on how HG was defined; reports of severe NVP were included where authors defined the condition as HG. We included descriptive epidemiological, case control and cohort study designs. Eligibility screening was performed in duplo. We extracted data on populations, study methods and outcomes of significance. A panel of patients reviewed the results and provided discussion and feedback. Quality was assessed with the JBI (2017) critical appraisal tool independently by two reviewers. We performed the searches on 1st November 2019. Our search yielded 4454 unique studies, of which five (n = 40,350 HG cases) matched eligibility criteria; One longitudinal and four population-based cohort studies from five countries. Follow-up ranged from 2 to 31 years. Definition of HG and data collection methods in all the studies created heterogeneity. Quality was low; studies lacked valid and reliable exposure, and/or follow-up was insufficient. Meta-analysis was not possible due to clinical and statistical heterogeneity. This systematic review found five heterogeneous studies reporting recurrence rates from 15 to 81%. Defining HG as hospital cases may have introduced detection bias and contribute to clinical heterogeneity. A prospective longitudinal cohort study using an internationally agreed definition of HG and outcomes meaningful to patients is required to establish the true recurrence rate of HG.

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.

Long-term cardiovascular morbidity following hyperemesis gravidarum: A Norwegian nationwide cohort study

Objective

To investigate whether exposure to hyperemesis gravidarum (hyperemesis) is associated with subsequent maternal cardiovascular morbidity.

Design

Nationwide cohort study.

Setting

Medical Birth Registry of Norway (1967–2002) linked to the nationwide Cardiovascular Disease in Norway project 1994–2009 (CVDNOR) and the Cause of Death Registry.

Population

Women in Norway with singleton births from 1967 to 2002, with and without hyperemesis, were followed up with respect to cardiovascular outcomes from 1994 to 2009.

Methods

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

Main outcome measures

The first hospitalisation due to nonfatal stroke, myocardial infarction or angina pectoris, or cardiovascular death.

Results

Among 989 473 women with singleton births, 13 212 (1.3%) suffered from hyperemesis. During follow-up, a total of 43 482 (4.4%) women experienced a cardiovascular event. No association was found between hyperemesis and the risk of a fatal or nonfatal cardiovascular event (adjusted HR 1.08; 95% CI 0.99–1.18). Women with hyperemesis had higher risk of hospitalisation due to angina pectoris (adjusted HR 1.28; 95% CI 1.15–1.44). The risk of cardiovascular death was lower among hyperemetic women in age-adjusted analysis (HR 0.73; 95% CI 0.59–0.91), but the association was no longer significant when adjusting for possible confounders.

Conclusion

Women with a history of hyperemesis did not have increased risk of a cardiovascular event (nonfatal myocardial infarction or stroke, angina pectoris or cardiovascular death) compared to women without.

Cardiovascular risk profile at the age of 40-45 in women with previous hyperemesis gravidarum or hypertensive disorders in pregnancy: A population-based study

OBJECTIVE

To assess midlife cardiovascular risk profiles in women with a history of hyperemesis or hypertensive disorders in pregnancy compared to women with none of the studied pregnancy complications.

STUDY DESIGN

Population-based study. Cardiovascular risk factors at the age of 40-45 among women with previous singleton births only were studied through linkage of the Norwegian Birth Registry and a Norwegian screening program (the Age 40 Program).

MAIN OUTCOME MEASURES

Family history of coronary heart disease, body mass index, smoking, physical activity, systolic and diastolic blood pressure, heart rate, cholesterol, triglycerides, antihypertensive treatment and diabetes.

RESULTS

Among 178,231 women participating in the Age 40 Program with previous singleton births; 2140 (1.2%) had experienced hyperemesis and 13,348 (7.5%) hypertensive disorders in pregnancy. Women who had suffered from hyperemesis were less physically active. The differences in mean systolic blood pressure and body mass index were probably clinically irrelevant. In women with a history of hypertensive disorders in pregnancy, systolic and diastolic blood pressure and body mass index were higher, and they were more likely to report diabetes in midlife. Women who had suffered from hyperemesis or hypertensive disorders in pregnancy were less likely to be daily smokers.

CONCLUSION

Women with hypertensive disorders in pregnancy seemed to have an unfavorable cardiovascular risk profile in midlife compared to women with uncomplicated pregnancies. In contrast there was no consistent evidence of increased risk subsequent to hyperemesis gravidarum. The proportion of daily smokers was lower in women with either of the two pregnancy complications.

Adverse Maternal and Birth Outcomes in Women Admitted to Hospital for Hyperemesis Gravidarum: a Population-Based Cohort Study

BACKGROUND

Evidence for risks of adverse maternal and birth outcomes in women with hyperemesis gravidarum (HG) is predominantly from small studies, unknown, or conflicting.

METHODS

A population-based cohort study using secondary health care records (Hospital Episode Statistics covering all of England from 1997 to 2012) was used to calculate odds ratios (OR) with 99% confidence intervals (CI) for the association between HG hospital admission and adverse outcomes, adjusting for maternal and pregnancy confounders.

RESULTS

Within 8 211 850 pregnancies ending in live births or stillbirths, women with HG had increased odds of anaemia (OR 1.28, 99% CI 1.23, 1.33), preeclampsia (OR 1.16, 99% CI 1.09, 1.22), eclampsia (OR 1.84, 99% CI 1.07, 3.18), venous thromboembolism antenatally (OR 1.94, 99% CI 1.57, 2.39 for deep vein thrombosis, and OR 2.54, 99% CI 1.89, 3.40 for pulmonary embolism) and post-partum. Odds of stillbirth (OR 0.77, 99% CI 0.66, 0.89) and post-term (OR 0.86, 99% CI 0.81, 0.92) delivery were decreased. Women were more likely to be induced (OR 1.20, 99% CI 1.16, 1.23), to deliver preterm (OR 1.11, 99% CI 1.05, 1.17), very preterm (OR 1.18, 99% CI 1.05, 1.32), or by caesarean section (OR 1.12, 99% CI 1.08, 1.16), to have low birthweight (OR 1.12, 99% CI 1.08, 1.17) or small for gestational age (OR 1.06, 99% CI 1.01, 1.11) babies and although absolute risks were small, their offspring were more likely to undergo resuscitation or neonatal intensive care.

CONCLUSION

HG may have important antenatal and postnatal consequences that should be considered in communications between health care professionals and women to best manage HG and prevent progression during pregnancy.

Validation of maternal reported pregnancy and birth characteristics against the Medical Birth Registry of Norway

Studies using mothers' self-reported information on birth and pregnancy characteristics are common, but the validity of such data is uncertain. We evaluated questionnaire data from the RHINE III study on reproductive health provided by 715 mothers from Bergen, Norway, about their 1629 births between 1967 and 2010, using the Medical Birth Registry of Norway (MBRN) as gold standard. Validity of dichotomous variables (gender, preterm birth [<37 weeks' gestation], postterm birth [>42 weeks' gestation], induction of labour, forceps delivery, vacuum delivery, caesarean section, were assessed by sensitivity, specificity, positive and negative predictive values (PPV and NPV) and Cohen's kappa. Paired t-test, Pearson's correlation coefficient and Bland-Altman plots were used to validate birthweight, stratified by mother's level of education, parity, birth year and child's asthma status. Child's gender and caesarean section showed high degree of validity (kappa = 0.99, sensitivity and specificity 100%). Instrumental delivery and extremely preterm birth showed good agreement with sensitivity 75-92%. Preterm birth and induction of labour showed moderate agreement. Post-term delivery was poorly reported. The validity appeared to be independent of recall time over 45 years, and of the child's asthma status. Maternally reported birth and pregnancy information is feasible and cheap, showed high validity for important birth and pregnancy parameters, and showed similar risk-associations compared to registry data.

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.

Hyperemesis gravidarum and risk of cancer in offspring, a Scandinavian registry-based nested case-control study

BACKGROUND

Hyperemesis gravidarum is a serious condition affecting 0.8-2.3% of pregnant women and can be regarded as a restricted period of famine. Research concerning potential long-term consequences of the condition for the offspring, is limited, but lack of nutrition in-utero has been associated with chronic disease in adulthood, including some cancers. There is growing evidence that several forms of cancer may originate during fetal life. We conducted a large study linking the high-quality population-based medical birth- and cancer registries in Norway, Sweden and Denmark, to explore whether hyperemesis is associated with increased cancer risk in offspring.

METHODS

A registry-based nested case-control study. Twelve types of childhood cancer were selected; leukemia, lymphoma, cancer of the central nervous system, testis, bone, ovary, breast, adrenal and thyroid gland, nephroblastoma, hepatoblastoma and retinoblastoma. Conditional logistic regression models were applied to study associations between hyperemesis and risk of childhood cancer, both all types combined and separately. Cancer types with five or more exposed cases were stratified by age at diagnosis. All analysis were adjusted for maternal age, ethnicity and smoking, in addition to the offspring's Apgar score, placental weight and birth weight. Relative risks with 95% confidence intervals were calculated.

RESULTS

In total 14,805 cases and approximately ten controls matched on time, country of birth, sex and year of birth per case (147,709) were identified. None of the cancer types, analyzed combined or separately, revealed significant association with hyperemesis. When stratified according to age at diagnosis, we observed a RR 2.13 for lymphoma among adolescents aged 11-20 years ((95% CI 1.14-3.99), after adjustment for maternal ethnicity and maternal age, RR 2.08 (95% CI 1.11-3.90)). The finding was not apparent when a stricter level of statistical significance was applied.

CONCLUSIONS

The main finding of this paper is that hyperemesis does not seem to increase cancer risk in offspring. The positive association to lymphoma may be by chance and needs confirmation.

Hyperemesis gravidarum and maternal cancer risk, a Scandinavian nested case-control study

Reproductive factors have been shown to influence cancer risk. Several pathological conditions during pregnancy have also been associated with subsequent altered cancer risk in the mother. Hyperemesis gravidarum (hyperemesis) is an early pregnancy condition characterized by severe nausea and vomiting resulting in weight loss and metabolic disturbances. Studies have reported associations between hyperemesis and cancer, but results are inconsistent. In this nested case-control study we linked the population-based medical birth registries and cancer registries in Norway, Sweden and Denmark in order to examine overall cancer risk and risk of specific cancer types in women with a history of hyperemesis, using conditional logistic regression. In total, 168,501 cases of cancer in addition to up to 10 cancer-free controls per case were randomly sampled, matched on year of birth and birth registry (n = 1,721,626). Hyperemesis was defined through the International Classification of Diseases. Analyses were adjusted for potential confounders. Hyperemesis was inversely associated with overall cancer risk with adjusted relative risk (aRR) of 0.93 (95% CI: 0.88-0.99), with cancer in the lungs (aRR: 0.60, 95% CI: 0.44-0.81), cervix (aRR: 0.66, 95% CI: 0.49-0.91) and rectum (aRR: 0.48, 95% CI: 0.29-0.78). Thyroid cancer was positively associated with hyperemesis (aRR 1.45, 95% CI: 1.06-1.99) and risk increased with more than one hyperemetic pregnancy (aRR 1.80, 95% CI: 1.23-2.63). Hormonal factors, in particular human chorionic gonadotropin, are likely to be involved in mediating these effects. This study is the first to systematically address these associations and provides valuable knowledge on potential long-term consequences of hyperemesis.

Risk of breast cancer following fertility treatment--a registry based cohort study of parous women in Norway

Despite increasing numbers of women availing themselves of assisted reproductive technology (ART), effects on cancer risk remain unresolved. Given hormonal exposures, breast cancer risk is of particular concern. The aim of this study is to investigate breast cancer risk amongst women giving birth following ART as compared to that amongst women who gave birth without ART. Data on all women who gave birth in Norway with or without ART, between 1984 and 2010 were obtained from the Medical Birth Registry of Norway (MBRN). 808,834 women eligible for study were linked to the Cancer Registry of Norway. Cox proportional models computed hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer between the two groups, adjusting for age, parity, age at first birth, calendar period and region of residence. In total, 8,037 women were diagnosed with breast cancer during the study period, 138 ART women and 7,899 unexposed. Total follow-up time was 12,401,121 person-years (median 16.0); median age at entry was 32.5 years (range 18.6-49.9) for ART women and 26.3 (range 10.5-54.6) for unexposed. Women exposed to ART had an elevated risk of breast cancer (adjusted HR 1.20, 95% CI 1.01-1.42). Subgroup analyses gave an HR of 1.30 (95% CI 1.07-1.57) for women treated with IVF and 1.35 (95 % CI 1.07-1.71) for women with follow-up >10 years, compared with controls. Our findings of increased risk in the study population warrant continued monitoring of women treated with ART as this population advances into more typical cancer age ranges.

Hyperemesis gravidarum and birth outcomes-a population-based cohort study of 2.2 million births in the Norwegian Birth Registry

OBJECTIVE

To study associations between hyperemesis gravidarum (HG) and birth outcomes.

DESIGN

Population-based cohort study.

SETTING

Norway.

SAMPLE

Singleton births in the Norwegian Birth Registry, 1967-2009 (n = 2 270 363).

METHODS

Multiple logistic regression was applied to study associations between HG and dichotomous outcomes; multiple linear regression to study associations between HG, birthweight and gestational length. Generalised estimating equations were applied to obtain valid standard errors. Sub-analysis on data with available information on smoking was conducted (1999-2009).

MAIN OUTCOME MEASURES

Small and large for gestational age (SGA/LGA), Apgar score after 5 minutes, very preterm and preterm birth (VPTB/PTB), perinatal death, stillbirth, neonatal death, birthweight and gestational length.

RESULTS

No associations between HG and adverse pregnancy outcomes were observed in crude analyses, except for VPTB (odds ratio [OR] 0.79, 95% CI 0.67-0.93). In adjusted analysis, HG was associated with perinatal death (OR 1.27, 95% CI 1.08-1.48). Inverse associations were observed between HG and VPTB (OR 0.80, 95% CI 0.68-0.94) and LGA (OR 0.95, 95% CI 0.90-0.99). Sub-analyses showed no associations between HG and perinatal death (OR 1.29, 95% CI 0.91-1.83). The inverse associations between HG, VPTB and LGA were strengthened (OR 0.66, 95% CI, 0.48-0.91 and OR 0.86, 95% CI 0.79-0.93, respectively). Exposed babies had reduced birthweight and gestational length compared with unexposed, adjusted difference - 21.4 g and - 0.5 days, respectively. Adjustment for smoking slightly strengthened the impact of HG on birthweight.

CONCLUSIONS

Inverse associations for HG and VPTB and LGA were observed. HG was associated with slight reductions in birthweight and gestational age.

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

INTRODUCTION

Studies have suggested a link between placental weight, placental weight-to-birth weight ratio (PW/BW) and adult health. Hyperemesis gravidarum (HG) may also have implications for adult health. No studies on HG and placental characteristics have been identified. We therefore explored the relationship between HG, placental weight and the PW/BW-ratio in a population-based cohort.

METHODS

Singleton births to primiparous women between 1999 and 2009 with data on HG, placental weight and birth weight in the Medical Birth Registry of Norway (MBRN) comprised the study base (n = 200,390). HG was defined through ICD-10 code 021.0, 021.1 and 021.9. Gender and gestational age specific percentile curves for placenta weight and PW/BW ratio were used to define those below the 10th and above the 90th percentile of both outcomes. Associations between HG and dichotomous outcomes were studied by multiple logistic regression. Multiple linear regression was applied to study placental weight as a continuous variable. Male and female offspring were analyzed separately.

RESULTS

The prevalence of HG was 1.2%. Women with HG and female offspring had significantly higher risk of a PW/BW-ratio above the 90th percentile (OR = 1.17, 95% CI: 1.03-1.34). HG and PW/BW-ratio below the 10th percentile were inversely associated (OR = 0.70, 95% CI: 0.56-0.89). For male offspring no association was observed for HG and PW/BW-ratio below the 10th or above the 90th percentile.

DISCUSSION/CONCLUSIONS

We observed positive associations between HG and high PW/BW ratio limited to female offspring only. The high PW/BW-ratio suggests that there may be a possible link between HG and adult health.

Triptan safety during pregnancy: a Norwegian population registry study

Knowledge on triptan safety during pregnancy remains limited to their class effect or studies on sumatriptan. Our aim was to evaluate the individual effect of four most frequently used triptans on several pregnancy outcomes. We used the Norwegian prescription database to access information on triptans redeemed by pregnant women living in Norway between 2004 and 2007. This database was linked to the Medical Birth Registry of Norway covering every institutional delivery in Norway and providing information on pregnancy, delivery, maternal and neonatal health. Estimates of associations with pregnancy outcomes were obtained by Generalised Estimation Equations analysis. Of the 181,125 women in our study, 1,465 (0.8%) redeemed triptans during pregnancy, and 1,095 (0.6%) redeemed triptans before pregnancy only (disease comparison group). The population comparison group comprised the remaining 178,565 women. Using this group as reference, we found no associations between triptan redemption during pregnancy and congenital malformations. Second trimester redemption was associated with postpartum haemorrhage (adjusted OR 1.57; 95% CI 1.19-2.07). The disease comparison group had an increased risk of major congenital malformations (adjusted OR 1.48; 95% CI 1.11-1.97), low birth weight (adjusted OR 1.39; 95% CI 1.08-1.81), and preterm birth (adjusted OR 1.30; 95% CI 1.06-1.60). The association of triptans with postpartum hemorrhage could be attributable to decreased platelet agreeability occurring in severe migraine. Likewise, the increased risk of major congenital malformations and other adverse pregnancy outcomes in the disease comparison group might be attributable to migraine severity.