Effect of pregnancy on postural tachycardia syndrome

Abstract

Objectives: To compare the clinical presentation, autonomic dysfunction, and pregnancy outcomes in parous and nulliparous women with postural tachycardia syndrome (POTS) and in women with POTS before and after pregnancy.

Patients and methods: This study consists of women who had at least 1 pregnancy during which time they met criteria for POTS between May 1993 and July 2009. All patients underwent standard autonomic testing. POTS was defined as a heart rate (HR) increase of greater than 30 beats/min on head-up tilt (HUT) with symptoms of orthostatic intolerance. Patients' charts were reviewed retrospectively to determine pregnancy outcomes.

Results: Clinical characteristics related to POTS did not differ between parous and nulliparous women except for disease duration (parous, 3.7+/-2.6; nulliparous, 2.1+/-2.2; P<.001). Autonomic dysfunction did not differ between groups (change in HR on HUT: parous, 42.6+/-12.0 beats/min; nulliparous, 41.3+/-10.6 beats/min; P=.39). Of 116 total pregnancies, adverse pregnancy outcomes were reported in 9% and maternal complications in 1%. No complication was related to POTS. There was a trend toward modest improvement in autonomic dysfunction before and after pregnancy (change in HR on HUT: before pregnancy, 38.1+/-22.7 beats/min; after pregnancy, 21.9+/-14.9 beats/min; P=.07).

Conclusion: The long-term impact of pregnancy on POTS does not appear to be clinically important. However, there does appear to be a trend toward improvement in the short-term postpartum period. Adverse pregnancy events were similar to those seen in the general public and do not present a barrier to women with POTS who want to have children.

FIGURE 1.

Heart rate changes in response to head-up tilt in parous vs nulliparous women. No significant difference in supine or standing (at 5 minutes) heart rate was noted between parous and nulliparous women (Mann-Whitney test, P=.57; P=.94, respectively). Heart rate increment on head-up tilt (standing – supine) also did not differ significantly (Mann-Whitney test, P=.39). Error bars show mean ± SD.

FIGURE 2.

Autonomic dysfunction, heart rate changes, and orthostatic intolerance (OI) prepregnancy and postpregnancy. Composite autonomic severity scores (CASS), including sudomotor subscores, adrenergic subscores, and totals, did not differ significantly prepregnancy and postpregnancy (paired t test, P=.48; P=.59; P=.81, respectively [n=9]). There was no significant difference in supine heart rate, standing heart rate (at 5 minutes), or heart rate increment on head-up tilt pre- and postpartum (paired t test, P=.29; P=.06; P=.07; respectively [n=10]). In addition, OI (as per the OI scale, see Patients and Methods section) did not differ significantly between groups (paired t test, P=.51 [n=10]). Error bars show mean ± SD.

FIGURE 3.

Orthostatic intolerance (OI) improved in the later stages of pregnancy. A nonsignificant trend toward a worsening of OI (as per the OI scale, see Patients and Methods section) was noted in the first trimester with subsequent improvement in the second and third trimesters (F=1.564; P=.20 [n=5]). Error bars show mean ± SD.