Discussion Questions

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  What was the study’s main objective?

  
  
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  What was the study design?

  
  
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  What were the outcomes of interest?

  
  
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  What were the key results?

  
  
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  What were the study’s strengths and weaknesses?

  
  
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  What is confounding by indication?

Introduction

Chronic hypertension in pregnancy boosts the risk for an array of adverse events, including maternal and fetal mortality. An estimated 1-5% of pregnancies are complicated by this disorder, but Orbach and colleagues note that its incidence can be expected to increase as rates of maternal obesity climb and as women postpone childbearing. The researchers, authors of a new study discussed by Journal Club members, have attempted to determine whether adverse perinatal outcomes occurring in this patient group are the result of the disease or of the drugs used to treat it. Data like these could help resolve which women are the best candidates for medication.

George A. Macones, MD, MSCE, Associate Editor

Introduction

Chronic hypertension in pregnancy boosts the risk for an array of adverse events, including maternal and fetal mortality. An estimated 1-5% of pregnancies are complicated by this disorder, but Orbach and colleagues note that its incidence can be expected to increase as rates of maternal obesity climb and as women postpone childbearing. The researchers, authors of a new study discussed by Journal Club members, have attempted to determine whether adverse perinatal outcomes occurring in this patient group are the result of the disease or of the drugs used to treat it. Data like these could help resolve which women are the best candidates for medication.

George A. Macones, MD, MSCE, Associate Editor

Study Design

Macones: Thank you for discussing this interesting article from Orbach and colleagues on antihypertensive drugs in pregnancy. What was the main objective of the study? Why is it an important topic?

Cahill: The main question that the authors addressed was whether the adverse pregnancy outcomes seen in women with chronic hypertension are caused by disease or whether the drugs used for treatment of hypertension are really the culprit. This is an issue that we all struggle with, so I do think it is a good question. It is certainly one that patients are interested in as well.

Macones: I agree. Can you describe the study design?

Cahill: Sure. This is a retrospective cohort study, which essentially means the authors identified groups of “exposed” women and then assessed a variety of outcomes in those exposed groups. The authors used 3 linked datasets in Southern Israel. Basically, they combined drug prescribing information from 1 dataset with information about demographics, medical conditions during pregnancy and delivery, delivery information, and discharge diagnoses from the other datasets. The exposed groups were made up of women with hypertension who were untreated and women with hypertension who were treated with methyldopa or atenolol. The unexposed group consisted of women without hypertension.

Macones: What were the outcomes of interest?

Odibo: I think it is a fairly standard set of outcomes when we think about hypertension—intrauterine growth restriction (IUGR), preterm delivery, low birthweight, perinatal mortality, low Apgar score, and preeclampsia. The only one that was a bit of a surprise to me was congenital malformations. I didn’t know of any issues raised between these specific antihypertensives and anomalies.

Macones: Do you have any specific comments about the analysis?

Odibo: The authors used standard bivariate statistics along with multivariate analysis. What’s missing for me are some of the details of the logistic regression models, such as how they selected what was in the models. But otherwise, I thought the analytic plan seemed reasonable.