A survey of Canadian practitioners regarding the management of the hypertensive disorders of pregnancy

Use of Antihypertensive Medications and Uterotonics During Delivery Hospitalizations in Women With Asthma

OBJECTIVE

To estimate whether the diagnosis of asthma is associated with the use of specific uterotonic and antihypertensive medications during delivery hospitalizations.

METHODS

We used Perspective, an administrative database, to determine whether women hospitalized for delivery complicated by postpartum hemorrhage or preeclampsia received uterotonics and antihypertensive medications differentially based on the absence or presence of asthma from 2006 to 2015. Given that carboprost and intravenous (IV) labetalol may be associated with asthma exacerbation, adjusted models for receipt of these medications were created with adjusted risk ratios with 95% CIs as measures of effect. Risk for status asthmaticus based on receipt of carboprost and IV labetalol was analyzed.

RESULTS

Over the study period, a total of 5,691,178 women were analyzed, of whom 239,915 (4.2%) had preeclampsia and 139,841 postpartum hemorrhage (2.5%). Carboprost was used less frequently in patients with asthma compared with patients with no asthma (11.4% vs 18.0%) in comparison with IV labetalol, which was used more commonly when a diagnosis of asthma was present (18.5% vs 16.7%). In unadjusted analysis, the presence of asthma was associated with a 37% decrease in likelihood of carboprost use and an 11% increase in likelihood of labetalol use. In adjusted analysis, the presence of asthma was associated with a 32% decrease in likelihood of carboprost use (adjusted risk ratio 0.68, 95% CI 0.62-0.74) compared with a 7% decrease in labetalol use (adjusted risk ratio 0.93, 95% CI 0.90-0.97). Risk for status asthmaticus was significantly increased with use of IV labetalol compared with other antihypertensive medications (6.5 vs 1.7/1,000 delivery hospitalizations, P<.01).

CONCLUSION

There may be an opportunity to reduce use of β-blockers and carboprost among patients with asthma. Given their association with status asthmaticus, these drugs should be used cautiously in women with asthma.

Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy

OBJECTIVE

This guideline summarizes the quality of the evidence to date and provides a reasonable approach to the diagnosis, evaluation and treatment of the hypertensive disorders of pregnancy (HDP).

EVIDENCE

The literature reviewed included the previous Society of Obstetricians and Gynaecologists of Canada (SOGC) HDP guidelines from 2008 and their reference lists, and an update from 2006. Medline, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Registry of Controlled Trials (CCRCT) and Database of Abstracts and Reviews of Effects (DARE) were searched for literature published between January 2006 and March 2012. Articles were restricted to those published in French or English. Recommendations were evaluated using the criteria of the Canadian Task Force on Preventive Health Care and GRADE.

Changes in fetal and maternal Doppler parameters observed during acute severe hypertension treatment with hydralazine or labetalol: a randomized controlled trial

We evaluated 16 pregnant women with gestational age between 20 and 32 weeks in acute severe hypertension which were randomly allocated to receive either hydralazine or labetalol. Blood pressure and Doppler ultrasound parameters from maternal uterine and fetal middle cerebral and umbilical arteries were assessed during acute severe hypertension and after treatment. A significant reduction in systolic and diastolic blood pressure was observed in both groups. A significant change in Doppler parameters was observed only in pregnant women who received hydralazine: an increase in uterine arteries resistance index. We concluded that both drugs were highly effective in reducing blood pressure in these women. Despite the observed increase in resistance index of uterine arteries associated with hydralazine, the use of hydralazine and labetalol were not related to any significant changes in fetal Doppler, which is reassuring about the safety of these drugs when treating acute severe hypertension in pregnancy.

Effects of guided imagery on blood pressure in pregnant women with hypertension: a pilot randomized controlled trial

BACKGROUND

Hypertension occurs in nearly 10 percent of pregnancies, and is associated with higher risk of infant and maternal morbidity and mortality than in normal pregnancies. Previous studies have suggested that relaxation therapies reduce blood pressure in nonpregnant adults. The objectives of this pilot randomized trial were to provide preliminary evidence of whether relaxation by means of guided imagery would reduce blood pressure in hypertensive pregnant women, and to assess the feasibility of a larger trial.

METHODS

A total of 69 pregnant women with hypertension were randomized to periods of guided imagery or of quiet rest, twice daily for 4 weeks or until delivery, whichever came first. Daytime ambulatory mean arterial pressure, systolic and diastolic blood pressure, and anxiety were measured weekly for up to 4 weeks.

RESULTS

Women allocated to guided imagery had lower mean arterial pressure elevations over time than those allocated to quiet rest (guided imagery: M = 1.58 mmHg, SD = 7.63; quiet rest: M = 5.93 mmHg, SD = 6.55; t = 2.36, p = 0.02). However, when adjusted for baseline mean arterial pressure and gestation, the effect was not significant (p = 0.14). Numbers of women prescribed antihypertensive medication postrandomization were similar (guided imagery: n = 16; quiet rest: n = 13, χ(2) = 0.74, p = 0.46). There was also no evidence of an effect on women's anxiety. Nearly 90 percent (n = 26) of the guided imagery group indicated that they would use it again.

CONCLUSIONS

Further rigorous study is warranted to determine effects of guided imagery on maternal blood pressure and perinatal health outcomes.

A Survey of Canadian Practitioners Regarding Diagnosis and Evaluation of the Hypertensive Disorders of Pregnancy

BACKGROUND

How Canadian practitioners are diagnosing and managing the hypertensive disorders of pregnancy (HDP), particularly in relation to the 1997 recommendations published by the Canadian Hypertension Society (CHS), is not known.

METHODS

A survey, with French and English versions (and covering diagnosis, evaluation, and management of pregnancy hypertension), was mailed to all members of the Society of Obstetricians and Gynaecologists of Canada (SOGC) (N = 1757, including obstetricians, family doctors practicing obstetrics, and midwives). Additionally, internists [i.e., all nephrologists (N = 191) and a random sample of 25% of general internists (N = 450)] registered with the Royal College of Physicians and Surgeons of Canada were sampled. The survey was distributed in two mailings and one reminder card. Data were entered into Microsoft Access, and Graph Pad Prism used to summarize responses [N (%)]. Differences in practice between specialties were examined, with a Bonferonni correction used to calculate a significant p value based on the number of comparisons and alpha of 0.05.

RESULTS

Respondents numbered 1187 (49.5%), with 466 not informative for the purpose of the study (due to retirement, or practices that do not include pregnant women with hypertension). The final analysis included 721 completed surveys. Most (609, 84.5% of) respondents take blood pressure (BP) with women in the sitting position, and use a mercury sphygmomanometer (79%) and the 5th Korotkoff (61%) sound to designate diastolic BP (dBP). To monitor pregnancies complicated by preeclampsia, most clinicians use the proposed laboratory tests of maternal well-being (usually at least once/week), fetal well-being [nonstress test (NST, at least once/week), and ultrasonographic studies (once weekly to every two weeks)]. There is general agreement that women with preeclampsia should be delivered for uncontrolled hypertension, end-organ dysfunction, or fetal compromise (nonreassuring NST, severe oligohydramnios, biophysical profile < 4, estimated fetal weight < 5th centile, and reversed end-diastolic flow by umbilical artery Doppler velocimetry). Less consensus was seen for delivery for preeclampsia at > 34 weeks, mild asymptomatic HELLP syndrome, hyperreflexia, and absent end-diastolic flow by umbilical artery Doppler velocimetry.

INTERPRETATION

This survey has clarified the current state of practice with respect to the diagnosis and evaluation of women with all types of HDP. In particular, we have identified areas of potential variability in BP measurement, and provided data on the feasibility of enrolling women with sub types of preeclampsia into intervention studies aimed at prolonging pregnancy.

Predicting adverse outcomes in women with severe pre-eclampsia

The reason pre-eclampsia matters so much to maternity care providers is that adverse maternal and perinatal events cluster around the diagnosis of proteinuric gestational hypertension. While that is true, most pre-eclampsia is mild and evanescent, resolving rapidly postpartum. Therefore, every effort must be made to identify those women at greatest personal risk, and those bearing fetuses at greatest risk, so that they can be offered closer surveillance and lower thresholds for the use of effective interventions, such as delivery and the use of MgSO(4). Conversely, as delivery remote from term can increase perinatal risks and as liberal MgSO(4) use is associated with maternal morbidity, it may be as important to identify those women who have "mild" disease and bear little personal and/or fetal actuarial risk. For women with "mild" disease at presentation, expectant management remote from term or nonuse of MgSO(4) would be appropriate. Through the PIERS (Pre-eclampsia Integrated Estimate of RiSk) model research program, we have determined that most criteria for "severe" disease perform poorly when operationalized to predict adverse maternal and/or perinatal outcomes. However, with standardized assessment and surveillance of women with suspected and confirmed pre-eclampsia it is possible to lower maternal risks both within individual institutions and across regions. In addition, the PIERS group developed, and is currently validating, 2 outcome prediction models (full-PIERS and mini-PIERS) that we hope will provide an evidence base for the definition of "severe" disease and guide clinical decision-making, especially remote from term when potential perinatal gains are so great.

The management of severe hypertension

Although definitions of severe hypertension vary, thresholds of >or=160-170 mm Hg systolic and/or >or=110 mm Hg diastolic are in most common usage. A recent focus has been placed on systolic hypertension given the increased pulse pressure in these women. In pregnancy, there is a general consensus that severe hypertension should be treated. Among woman with pre-eclampsia, attention must be paid to other end organ dysfunction, as blood pressure (BP) management is but one aspect of care. The urgency of antihypertensive therapy will depend primarily on the absolute level of BP. However, most clinicians will also consider both the rate of BP rise and the presence of maternal symptoms. Most commonly, severe hypertension is treated with parenteral labetalol or hydralazine, or oral nifedipine (capsules or PA tablet). Other options will depend on local availability. MgSO(4) should not be relied on as an antihypertensive.

Exercise or other physical activity for preventing pre-eclampsia and its complications

BACKGROUND

The association between an increase in regular physical activity and a reduction in the risk of hypertension is well documented for non-pregnant people. It has been suggested that exercise may help prevent pre-eclampsia and its complications. Possible adverse effects of increased physical activity during pregnancy, particularly on the risk of preterm birth and fetal growth restriction, are unclear. It is, therefore, important to assess whether exercise reduces the risk of pre-eclampsia and its complications and, if so, whether these benefits outweigh the risks.

OBJECTIVES

To assess the effects of exercise, or increased physical activity, on prevention of pre-eclampsia and its complications.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 1), and EMBASE (2002 to February 2005).

SELECTION CRITERIA

Studies were included if these were randomised trials evaluating the effects of exercise or increased physical activity during pregnancy for women at risk of pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Data were entered on Review Manager software for analysis, and double checked for accuracy.

MAIN RESULTS

Two small, good quality trials (45 women) were included. Both compared moderate intensity regular aerobic exercise with maintenance of normal physical activity during pregnancy. The confidence intervals were wide and crossed the line of no effect for all reported outcomes including pre-eclampsia (relative risk 0.31, 95% confidence interval 0.01 to 7.09).

AUTHORS' CONCLUSIONS

There is insufficient evidence for reliable conclusions about the effects of exercise on prevention of pre-eclampsia and its complications.

Rest during pregnancy for preventing pre-eclampsia and its complications in women with normal blood pressure

BACKGROUND

Women at risk of pre-eclampsia or gestational hypertension are sometimes advised to rest. Whether this, overall, does more good than harm is unclear.

OBJECTIVES

To assess the effects of rest or advice to reduce physical activity during pregnancy for preventing pre-eclampsia and its complications in women with normal blood pressure.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), and EMBASE (2002 to August 2005).

SELECTION CRITERIA

Studies were included if they were randomised trials evaluating the effects of rest or advise to reduce physical activity for preventing pre-eclampsia and its complications in women with normal blood pressure.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Data were double checked for accuracy.

MAIN RESULTS

Two small trials (106 women) of uncertain quality were included. Both recruited women with a singleton pregnancy at moderate risk of pre-eclampsia from 28 to 32 weeks' gestation. There was a statistically significant reduction in the relative risk of pre-eclampsia with four to six hours rest per day (one trial, 32 women; relative risk (RR) 0.05, 95% confidence interval (CI) 0.00 to 0.83), but not of gestational hypertension (RR 0.25, 95% CI 0.03 to 2.00), compared to normal activity. Rest of 30 minutes per day plus nutritional supplementation was associated with a reduction in the risk of pre-eclampsia (one trial, 74 women; RR 0.13, 95% CI 0.03 to 0.51) and also of gestational hypertension (RR 0.15, 95% CI 0.04 to 0.63). The effect on caesarean section was unclear (RR 0.82, 95% CI 0.48 to 1.41). No other outcomes were reported.

AUTHORS' CONCLUSIONS

Daily rest, with or without nutrient supplementation, may reduce the risk of pre-eclampsia for women with normal blood pressure, although the reported effect may reflect bias and/or random error rather than a true effect. There is no information about outcomes such as perinatal mortality and morbidity, maternal morbidity, women's views, adverse effects, and costs. Current evidence is insufficient to support recommending rest or reduced activity to women for preventing pre-eclampsia and its complications. Whether women rest during pregnancy should therefore be a matter of personal choice.

Cesarean section at 28 weeks' gestation with resection of pheochromocytoma: perioperative antihypertensive management

Pregnancy complicated by pheochromocytoma is potentially fatal. Pregnancy and labor increase the risk of hypertensive crisis as it may occur with the sudden release of catecholamine accompanying uterine contractility and straining. However, antepartum diagnosis reduces both maternal and fetal mortality, allowing for safe cesarean section and resection of tumor. We describe the management of perioperative hypertension for combined cesarean section and pheochromocytoma resection.

Nifedipine for Severe Hypertension in Pregnancy: Emotion or Evidence?

A meta-analysis of randomized controlled trials suggests that nifedipine appears to be a reasonable agent for treatment of acute severe hypertension in pregnancy. However, in a 1999 survey of Canadian practitioners, most stated that they rarely or never use nifedipine capsules for treatment of acute severe pregnancy hypertension. Also, there are case reports of adverse outcomes following use of nifedipine capsules in pregnancy, although the risks appear to have been overplayed. We suggest that a reasonable approach is ongoing use of nifedipine capsules, with perhaps an initial dosage of 5 mg rather than 10 mg. Having women swallow the capsule without first biting it may also be a prudent approach, because there is insufficient information from most of the published clinical trials to say exactly how the nifedipine capsules were administered. Further, use of the 10 mg nifedipine prolonged action tablet may also be a reasonable approach for treatment of severe hypertension in pregnancy, although more data are needed. Such research would be particularly relevant given that nifedipine appears to be a promising treatment for spontaneous preterm labour. We must resist the temptation to throw out of our limited therapeutic armamentarium an effective oral preparation before adequately considering the evidence.

Labor analgesia for the parturient with pregnancy-induced hypertension: what does an obstetrician need to know?

INTRODUCTION

Pregnancy-induced hypertension (PIH), also known as preeclampsia, remains one of the leading causes of maternal death worldwide. The term preeclampsia describes the development of hypertension with proteinuria and/or pathologic edema after the 20th week of gestation. The parturient with PIH usually has multiple organ alterations, which may affect the selection of analgesia and anesthesia for labor and delivery.

DISCUSSION

This article reviews the special concerns posed by PIH, one of the most common medical conditions encountered in pregnancy.

Variations in Early and Intermediate Neonatal Outcomes for Inborn Infants Admitted to a Canadian NICU and Born of Hypertensive Pregnancies

OBJECTIVE

To determine whether neonatal intensive care unit (NICU) outcomes vary by centre for inborn neonates of hypertensive pregnancies and, if so, whether that variation might be related to between-centre variations in obstetric practice.

METHODS

The study comprised a prospective cohort of 13 505 singleton neonates admitted to 17 Canadian NICUs. Adjusting for potential confounders, we used multivariate regression to analyze the relation between centre of delivery and 6 dependent variables: (1) Apgar score < 7 at 5 minutes; (2) Score of Neonatal Acute Physiology-II (SNAP-II) score > or = 10; (3) neonatal death; (4) neonatal death or morbidity (owing to bronchopulmonary dysplasia [BPD], intraventricular hemorrhage [IVH], necrotizing enterocolitis [NEC], persistent ductus arteriosus [PDA], or periventricular leukomalacia [PVL]); (5) BPD alone; and (6) major neonatal morbidity (that is, at least one of IVH, PVL, NEC, or PDA). NICU practices known to influence these outcomes were included in the modelling for neonatal death and neonatal morbidity. In a sensitivity analysis for practice variation, antenatal steroid exposure was both included and excluded in each regression.

RESULTS

For 5 of the 6 dependent variables, we identified between-centre variation that was not explained solely by variation in antenatal corticosteroid use. Adjusted odds ratios varied from 0.11 to 5.6 (the reference centre was the median rate of the adverse outcome).

CONCLUSIONS

In the pregnancy hypertension setting, between-centre variations in practice are associated with variations in neonatal physiology and survival. For infants admitted to NICU, the obstetric management of hypertensive pregnancies appears to have an effect on both short- and medium-term neonatal outcomes, even after correction for NICU management.