Prevalence of White Coat Hypertension and White Coat Effect in Healthy and Hypertensive Pregnancy

Objective: Recognition of white coat effect/hypertension (WCE/WCH) in pregnancy is important to avoid unnecessary treatment and also requires monitoring as a risk factor for complications. Data on WCE/WCH frequency in pregnancy are scarce and usually higher (25-50%) compared with general population (15-35%). Aim of study was to assess prevalence of WCE/WCH in pregnancy by comparison of rigorous office blood pressure measurement (OBPM) with results of home (HBPM) and 24-hour monitoring (ABPM) in real clinical setting with regard to hypertensive status and time of pregnancy.Design and method: Prospective longitudinal study, 214 pregnant women admitted 2017-2023 to outpatient clinic with BP examined monthly in pregnancy, 6-8 weeks, 6 months, 1 year postpartum. On each occasion data on HBPM (from 7 days prior) were collected, compared with OBPM: measured in standardized conditions 3x3 times: with(I), without(II) and again with(III) the presence of physician (MicrolifeWatchBP) in quiet surrounding, as well as with regular clinical BP measurement (OMRON®-705I), followed by 24hABPM (AND®TM-2430). Pharmacotherapy in hypertensives was managed in accordance with ESH/ESC guidelines, good BP control was achieved throughout the study. Results: 40 normotensive controls, 201 hypertensive women (145 chronic;56 pregnancy induced) were recruited, preeclampsia developed in 49 of hypertensives (HT+PE). In general, WCE/WCH (at least one OBPM too high, both HBPM and ABPM normal) was detected at least once per observation in 10.8% of controls, 11.3% of HT group and in 4.7% HT+PE. When OBPM was compared to HBPM only WCH/WCE was present in 13%, 33.3% and 27.9% of groups respectively, while for comparison with dayABPM in 15%, 18% and 16.3%. Prevalence of WCE/WCH divided into trimesters and postpartum, in relation to OBPM measurement conditions are shown in table 1 for comparison with HBPM, and in table 2 for comparison with ABPM. Conclusions: WCE/WCH was more often found in hypertensive pregnancy than in normotensive. Prevalence of WCE/WCH seems to be less often found than previously reported when OBPM is repeated and standardized conditions of measurement rigorously followed. Repeated and unattended by the medical staff measurements in the office lower the occurrence of WCE/WCH although this effect is less pronounced in 3rd trimester of pregnancy.