Knowledge of the absolute risk (AR) for venous thromboembolism (VTE) in women around pregnancy and how potential risk factors modify this risk is crucial in identifying women who would benefit most from thromboprophylaxis. We examined a large primary care database containing 376 154 pregnancies ending in live birth or stillbirth from women aged 15 to 44 years between 1995 and 2009 and assessed the effect of risk factors on the incidence of antepartum and postpartum VTE in terms of ARs and incidence rate ratios (IRR), using Poisson regression. During antepartum, varicose veins, inflammatory bowel disease (IBD), urinary tract infection, and preexisting diabetes were associated with an increased risk for VTE (ARs, ≥139/100 000 person-years; IRRs, ≥1.8/100 000 person-years). Postpartum, the strongest risk factor was stillbirth (AR, 2444/100 000 person-years; IRR, 6.2/100 000 person-years), followed by medical comorbidities (including varicose veins, IBD, or cardiac disease), a body mass index (BMI) of 30 kg/m² or higher, obstetric hemorrhage, preterm delivery, and caesarean section (ARs, ≥637/100 000 person-years; IRRs, ≥1.9/100 000 person-years). Our findings suggest that VTE risk varies modestly by recognized factors during antepartum; however, women with stillbirths, preterm births, obstetric hemorrhage, caesarean section delivery, medical comorbidities, or a BMI of 30 kg/m² or higher are at much higher risk for VTE after delivery. These risk factors should receive careful consideration when assessing the potential need for thromboprophylaxis during the postpartum period. Key Points Antepartum, we found that established risk factors only had a modest effect on rates of VTE. Postpartum, we found that among other factors, women with stillbirth or preterm birth had high rates of VTE.

What are the maternal risk factors for hyperemesis gravidarum (HG) hospital admission, readmission and reoccurrence in a following pregnancy? Young age, less socioeconomic deprivation, nulliparity, Asian or Black ethnicity, female fetus, multiple pregnancy, history of HG in a previous pregnancy, thyroid and parathyroid dysfunction, hypercholesterolemia and Type 1 diabetes are all risk factors for HG. Women with Black or Asian ethnicity, of young age, carrying multiple babies or singleton females, with Type 1 diabetes or with a history of HG were previously reported to be at higher risk of developing HG; however, most evidence is from small studies. Little is known about associations with other comorbidities and there is controversy over other risk factors such as parity. Estimates of HG prevalence vary and there is a little understanding of the risks of HG readmission in a current pregnancy and reoccurrence rates in subsequent pregnancies, all of which are needed for planning measures to reduce onset or worsening of the condition. We performed a population-based cohort study of pregnancies ending in live births and stillbirths using prospectively recorded secondary care records (Hospital Episode Statistics) from England. We analysed those computerized and anonymized clinical records from over 5.3 million women who had one or more pregnancies between 1997 and 2012. We obtained 8 215 538 pregnancies from 5 329 101 women of reproductive age, with a total of 186 800 HG admissions occurring during 121 885 pregnancies. Multivariate logistic regression with generalized estimating equations was employed to estimate odds ratios (aOR) to assess sociodemographic, pregnancy and comorbidity risk factors for HG onset, HG readmission within a pregnancy and reoccurrence in a subsequent pregnancy. Being younger, from a less socioeconomically deprived status, of Asian or Black ethnicity, carrying a female fetus or having a multiple pregnancy all significantly increased HG and readmission risk but only ethnicity increased reoccurrence. Comorbidities most strongly associated with HG were parathyroid dysfunction (aOR = 3.83, 95% confidence interval 2.28–6.44), hypercholesterolemia (aOR = 2.54, 1.88–3.44), Type 1 diabetes (aOR = 1.95, 1.82–2.09), and thyroid dysfunction (aOR = 1.85, 1.74–1.96). History of HG was the strongest independent risk factor (aOR = 4.74, 4.46–5.05). Women with higher parity had a lower risk of HG compared with nulliparous women (aOR = 0.90, 0.89–0.91), which was not explained by women with HG curtailing further pregnancies. Although this represents the largest population-based study worldwide on the topic, the results could have been biased by residual and unmeasured confounding considering that some potential important risk factors such as smoking, BMI or prenatal care could not be measured with these data. Underestimation of non-routinely screened comorbidities such as hypercholesterolemia or thyroid dysfunction could also be a cause of selection bias. The estimated prevalence of 1.5% from our study was similar to the average prevalence reported in the literature and the representativeness of our data has been validated by comparison to national statistics. Also the prevalence of comorbidities was mostly similar to other studies estimating these in the UK and other developed countries. Women with Black or Asian ethnicity, of young age, carrying multiple babies or singleton females, with Type 1 diabetes or with history of HG were confirmed to be at higher risk of HG with an unprecedented higher statistical power. We showed for the first time that socioeconomic status interacts with maternal age, that hypercholesterolemia is a potential risk factor for HG and that carrying multiple females increases risk of hyperemesis compared with multiple males. We also provided robust evidence for the association of parity with HG. Earlier recognition and management of symptoms via gynaecology day-case units or general practitioner services can inform prevention and control of consequent hospital admissions. The work was founded by The Rosetrees Trust and the Stoneygate Trust. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. C.N.-P. reports personal fees from Sanofi Aventis, Warner Chilcott, Leo Pharma, UCB and Falk, outside the submitted work and she is one of the co-developers of the RCOG Green Top Guideline on HG; all other authors did not report any potential conflicts of interest. Not applicable.

Objective: To estimate risks of major congenital anomaly (MCA) among children of mothers prescribed antidepressants during early pregnancy or diagnosed with depression but without antidepressant prescriptions.Design: Population‐based cohort study.Setting: Linked UK maternal–child primary care records.Population: A total of 349 127 singletons liveborn between 1990 and 2009.Methods: Odds ratios adjusted for maternal sociodemographics and comorbidities (aORs) were calculated for MCAs, comparing women with first‐trimester selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) and women with diagnosed but unmedicated depression, or women without diagnosed depression.Main outcome measures: Fourteen system‐specific MCA groups classified according to the European Surveillance of Congenital Anomalies and five specific heart anomaly groups.Results: Absolute risks of MCA were 2.7% (95% confidence interval, 95% CI, 2.6–2.8%) in children of mothers without diagnosed depression, 2.8% (95% CI 2.5–3.2%) in children of mothers with unmedicated depression, and 2.7% (95% CI 2.2–3.2%) and 3.1% (95% CI 2.2–4.1%) in children of mothers with SSRIs or TCAs, respectively. Compared with women without depression, MCA overall was not associated with unmedicated depression (aOR 1.07, 95% CI 0.96–1.18), SSRIs (aOR 1.01, 95% CI 0.88–1.17), or TCAs (aOR 1.09, 95% CI 0.87–1.38). Paroxetine was associated with increased heart anomalies (absolute risk 1.4% in the exposed group compared with 0.8% in women without depression; aOR 1.78, 95% CI 1.09–2.88), which decreased marginally when compared with women with diagnosed but unmedicated depression (aOR 1.67, 95% CI 1.00–2.80).Conclusions: Overall MCA risk did not increase with maternal depression or with antidepressant prescriptions. Paroxetine was associated with increases of heart anomalies, although this could represent a chance finding from a large number of comparisons undertaken.