The effect of obesity and position on heart rate in pregnancy

OBJECTIVE

To determine the prevalence of resting sinus tachycardia among pregnant women during routine third-trimester antenatal visits, and to determine the relationship between body mass index (BMI) and heart rate.

METHODS

In this cross-sectional study, pregnant women at 32-40 weeks' gestation were evaluated at routine antenatal visits between September 1996 and August 1997. Patients with medical disorders were excluded. Height, weight and pulse in both the sitting and the left lateral recumbent position were obtained. BMI was based on current weight, and those with a BMI of > or = 30 kg/m2 were classified as obese. Sinus tachycardia was defined as a heart rate of > or = 100 beats/min.

RESULTS

The prevalence of tachycardia was 39% (n = 93) when seated, and 29% on the left side. The corresponding rates of sinus tachycardia when seated for obese (n = 31) and non-obese (n = 62) pregnant women were 58% and 29% (relative risk 2.0, 95% confidence interval 1.2, 3.3). However, the rates of tachycardia on the left side were not significantly different: 32% for obese and 27% for non-obese (relative risk 1.2, 95% confidence interval 0.6, 2.3).

CONCLUSION

Resting tachycardia during routine antenatal visits may be more common than was previously recognized, and the majority of obese pregnant women are tachycardic when seated. When obese women are tachycardic in the seated position their heart rate should be reassessed after 5 min in the left lateral recumbent position.

Drugs in pregnancy. Respiratory disease

Respiratory illnesses are the commonest cause of patient visits to physicians. Although the common cold, sinusitis and bronchitis may be lacking in drama, they account for a substantial amount of morbidity among women of reproductive age and are frequently encountered by physicians caring for pregnant women. Present knowledge about the management of these common conditions and the safety of the medications often used to treat them are reviewed in this chapter. Asthma and community-acquired pneumonia are more serious respiratory illnesses that are also often encountered in pregnancy. Present evidence suggests that community-acquired pneumonia is best treated empirically, with additional investigation usually necessary only if there is a failure of initial treatment. The recognition of asthma as an inflammatory condition has led to a very specific approach to its management that can readily and safely be applied to the pregnant woman. Treatment of HIV and tuberculosis should not be withheld during pregnancy because of the life-threatening nature of these infections and the importance of preventing vertical transmission.

Alveolar-arterial oxygen gradient in acute pulmonary embolism in pregnancy

OBJECTIVE

Our goal was to determine the prevalence of normal alveolar-arterial gradients in pregnant patients with documented pulmonary embolism.

STUDY DESIGN

A retrospective chart review was performed on all pregnant women with pulmonary embolism at two large obstetric centers between 1990 and 1995. Alveolar-arterial gradients were calculated from room air arterial blood gas values and compared with values from patients who had been established as normal.

RESULTS

Ten of 17 patients with pulmonary embolism identified had alveolar-arterial gradients that were normal.

CONCLUSIONS

In our study 58% of pregnant women with documented pulmonary embolism had a normal alveolar-arterial gradient. This markedly differs from the published data in nonpregnant patients, in which the incidence of normal alveolar-arterial gradients in pulmonary embolism has ranged from 1.9% to 20%. This suggests that the alveolar-arterial gradient should not be used to determine the likelihood of pulmonary embolism in pregnant women because this could lead to the withholding of appropriate treatment for this life-threatening condition.

Diabetes insipidus in pregnancy: a treatable cause of oligohydramnios

BACKGROUND

Diabetes insipidus, which presents with polyuria, polydipsia, and profound electrolyte abnormalities, occurs rarely in pregnancy. We report a patient with severe oligohydramnios that resolved after treatment of diabetes insipidus.

CASE

A 14-year-old girl was admitted at 33 weeks' gestation with cramping and vaginal spotting. A sonogram indicated oligohydramnios and an amniotic fluid index (AFI) of 2.6, with normal fetal kidneys and bladder. On hospital day 2, the AFI was 0.0. Recorded fluid was 8 L in and 13.6 L out. Serum sodium was 153 mEq/L. Diabetes insipidus was diagnosed and treated with intranasal desmopressin acetate. The oligohydramnios resolved rapidly, and the patient delivered a healthy 2700-g male infant at 38 weeks.

CONCLUSION

Although rare, diabetes insipidus may present initially in pregnancy and should be considered in patients with oligohydramnios. Simple diagnosis with determination of 24-hour urine volume and serum electrolytes can identify this potentially reversible cause of oligohydramnios and poor obstetric outcome.