Physical Exertion Immediately Prior to Placental Abruption

A Case-Crossover Study

Harpreet S. Chahal; Bizu Gelaye; Elizabeth Mostofsky; Sixto E. Sanchez; Murray A. Mittleman; Malcolm Maclure; Percy Pacora; Jose A. Torres; Roberto Romero; Cande V. Ananth; Michelle A. Williams

Disclosures

Am J Epidemiol. 2018;187(10):2073-2079. 

In This Article

Abstract and Introduction

Abstract

While there is consistent evidence that episodes of physical exertion are associated with an immediately higher risk of acute ischemic vascular events, the risk of placental abruption immediately following episodes of physical exertion has not been studied. In a multicenter case-crossover study, we interviewed 663 women with placental abruption at 7 Peruvian hospitals between January 2013 and August 2015. We asked women about physical exertion in the hour before symptom onset and compared this with their frequency of physical exertion over the prior week. Compared with times with light or no exertion, the risk of placental abruption was 7.8 (95% confidence interval (CI): 5.5, 11.0) times greater in the hour following moderate or heavy physical exertion. The instantaneous incidence rate ratio of placental abruption within an hour of moderate or heavy physical exertion was lower for women who habitually engaged in moderate or heavy physical activity more than 3 times per week in the year before pregnancy (rate ratio (RR) = 3.0, 95% CI: 1.6, 5.9) compared with more sedentary women (RR = 17.3, 95% CI: 11.3, 26.7; P for homogeneity < 0.001), and the rate ratio was higher among women with preeclampsia/eclampsia (RR = 13.6, 95% CI: 7.0, 26.2) than among women without (RR = 6.7, 95% CI: 4.4, 10.0; P for homogeneity = 0.07).

Introduction

Placental abruption—the premature separation of the implanted placenta—is an obstetrical complication that affects roughly 1%–2% of all pregnancies.[1] Potential sequelae of placental abruption include hemorrhagic shock, coagulopathy, disseminated intravascular coagulation, uterine rupture, and renal failure. In more and less developed countries alike, placental abruption, along with infection and hypertensive disorders, continues to appear among the top 3 causes of maternal mortality. In addition to its impact on women, placental abruption is also a significant cause of infant morbidity and mortality.[2–4]

Despite its acute clinical presentation, placental abruption is characterized by both acute and chronic pathophysiologic features. The specific etiology of placental abruption is still unknown, but its underlying mechanisms include uteroplacental underperfusion,[5,6] ischemia,[7,8] and chronic hypoxemia.[9] While there is a substantial body of evidence showing an acutely heightened risk of ischemic cardiovascular events immediately following physical exertion,[10] the association between physical exertion and the acute risk of placental abruption—"an ischemic placental disorder"[7,11–13]—has not yet been investigated. Similar to cardiovascular disorders, habitual physical activity among pregnant women is associated with several health benefits over the long-term, including a lower baseline risk of several maternal[14–17] and fetal[18] outcomes.

We used a case-crossover design to compare each woman's risk of placental abruption in the hour following episodes of physical exertion with that same woman's risk at other times. We examined whether moderate or heavy physical exertion was associated with an immediately higher risk of placental abruption and whether the risk was different for moderate versus heavy physical exertion. We also evaluated whether the association varied according to habitual physical activity or with comorbid hypertensive disorders of pregnancy (i.e., preeclampsia or eclampsia).

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