Safety and clinical role of the exercise testing during pregnancy

Abstract Aims The prevalence of arterial hypertension (AH) during pregnancy is ranging from 2% to 10%. Diagnostic criteria are based on rest blood pressure measurements. Exercise testing (ET) is a useful approach to detect latent hypertensive condition and may allow early diagnosis. Despite physical activity is encouraged during pregnancy in order to prevent systemic disorders, ET is not commonly performed during pregnancy due to limited data of safety. The aim of the study is to test the safety of ET during pregnancy and to explore its role in predicting the development of AH. Methods Pregnant women were tested through submaximal ET at Dyspnoea Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico of Milano. The exercise was performed on a stationary cycle on which the power was increased of 15 W every 2 min starting from 5 W (first step). Subjects were continuously monitored during exercise through EKG, non-invasive blood pressure measurements every 2 min and peripheral oxygen saturation. 3 months clinical follow-up was made in order to assess the presence of AH or other pregnancy disorders. U-test analysis was performed in order to verify statistical difference between hypertensive and non-hypertensive women. Heart rate, systolic and diastolic blood pressure (SBP and DBP) were measured at rest, at the first step and at peak of ET and have been considered in analysis. U-test (Mann–Whitney analysis) was adopted to test difference between hypertensive and non-hypertensive group. Women were followed-up at second trimester (22nd–25th week of pregnancy) in order to monitor the clinical condition, the development of AH or any gestational disorders (e.g. diabetes and pre-eclampsia). Results All 73 women (mean age 32 years, gestational age 12–14 weeks) consecutively enrolled have completed the ET. The mean maximum load achieved was 65 W, no abrupt interruption of ET was needed because of symptoms or intolerance. Mean HR at rest, at the first step and at the peak was 80 b.p.m., 91 b.p.m. and 128 b.p.m., respectively. Mean arterial pressure reached values of 97/62 mmHg at rest, 107/66 mmHg at the first step and 140/73 mmHg at peak exercise. At follow-up 9 of 73 showed clinical disorders (12%) of which 5 patients had hypertension (6.8%), 3 patients had diabetes (4.1%) and 1 had pre-eclampsia (1.4%). Comparing the group with AH (n 5) with the group without AH (n 68), SBP at the first step (median values 127 mmHg vs 104 mmHg, P = 0.009), the DBP at rest (median values 72 mmHg vs 60 mmHg, P = 0.039) and the DBP at the peak (median values 90 mmHg vs 69.5 mmHg, P = 0.038) were significantly higher in the group with AH. Among these parameters a logistic regression selected the SBP as best predictor for developing AH (OR 1.139, 95% IC 029–1.261, P = 0.012). Conclusions Our results showed that submaximal ET is safe in pregnancy. Although limited, our data seem to support the validity of ET, even submaximal, in order to stratify the risk of developing AH in pregnancy. Moreover, even SBP response at first step could be considered in a normal and expected range, we can speculate that a relatively excessive increase of BP in the early phase of exercise could reflect a pre-clinical impairment of vascular compliance predisposing AH during the second gestational trimester. Further data are needed to validate our results.