Relationship between body mass index and mean arterial pressure in normotensive and chronic hypertensive pregnant women: a prospective, longitudinal study.

BACKGROUND: Being overweight is associated with both higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) during pregnancy and increased risk of gestational hypertensive disorders. The objective of this study was to determine and quantify the effect of body mass index (BMI) on mean arterial pressure (MAP) at several time points throughout pregnancy in normotensive (NT) and chronic hypertensive pregnant (HT) women. METHODS: A prospective longitudinal study was carried out in 461 singleton pregnancies (429 low-risk and 32 with chronic arterial hypertension), with measurements taken at the 1(st), 2(nd), and 3(rd) trimesters and at delivery. Linear mixed-effects regression models were used to evaluate the time-progression of BMI, SBP, DBP and MAP during pregnancy (NT vs. HT). The longitudinal effect of BMI on MAP, adjusted for the hypertensive status, was investigated by the same methodology. RESULTS: BMI consistently increased with time in both NT and HT women. In contrast, MAP decreased during the first half of pregnancy, after which it increased until the moment of delivery in both groups. A 5-unit increase in BMI was predicted to produce an increase of approximately 1 mmHg in population MAP values. This effect is independent from the time period and from hypertensive status. CONCLUSIONS: In both NT and HT pregnant women, MAP is strongly (and significantly) influenced by increases in BMI.

Uterine artery Doppler in the management of early pregnancy loss: a prospective, longitudinal study.

BACKGROUND: The pharmacological management of early pregnancy loss reduced substantially the need for dilation and curettage. However, prognostic markers of successful outcome were not established. Thus the major purpose of this study was to determine the sensitivity and specificity of the uterine artery pulsatility (PI) and resistance (RI) indices to detect early pregnancy loss patients requiring dilation and curettage after unsuccessful management. METHODS: A cohort prospective observational study was undertaken to include women with early pregnancy loss, ≤ 12 weeks of gestation, managed with mifepristone (200 mg) and misoprostol (1600 µg) followed by PI and RI evaluation of both uterine arteries 2 weeks after. At this time, in 173/315 patients, incomplete miscarriage was diagnosed. Among them, 32 underwent uterine dilatation and curettage at 8 weeks of follow-up. RESULTS: The cut-off points for the uterine artery PI and RI, leading to the maximum values of sensitivity (69.5%, CI95%: 61.5%-76.5% and 75.0%, CI95%: 57.9%-86.8%, respectively) and specificity (75.0%, CI95%: 57.9%-86.8% and 65.6%, CI95%: 48.3%-79.6%, respectively), for the discrimination between the women who needed curettage from those who resolved spontaneously were 2.8 and 1, respectively. CONCLUSIONS: The potential usefulness of uterine artery Doppler evaluation to predict the need for uterine curettage in patients submitted to medical treatment for early pregnancy loss was demonstrated.

Uterine artery impedance during puerperium in normotensive and chronic hypertensive pregnant women.

PURPOSE: The present study compared the Doppler flow pulsatility indices (PI) in the uterine arteries (UtA) during the puerperium between healthy women and those with stage-1 essential hypertension who had uncomplicated pregnancies and delivered by elective caesarean section. The change in the mean arterial pressure (MAP) and body mass index (BMI) over time was also assessed. METHODS: A longitudinal and prospective study was performed in singleton pregnancies of 28 normotensive (NT) and 24 hypertensive (HT) women. The UtA-PI was measured immediately before caesarean section (time 0) and at 1 week (time 1) and 4 weeks (time 2) postpartum. The presence or absence of early diastolic notches was recorded. The change in the MAP, BMI, and UtA-PI over time and between the two populations was modelled through multivariate linear regression using the generalised least squares. RESULTS: In both groups, the UtA-PI significantly increased from time 0 to time 1 (p < 0.05) and time 2 (p < 0.05). Stage-1 hypertension did not change the trend but did increase the UtA-PI magnitude (p < 0.05). The presence of uterine artery notching increased over time, from 6 to 98%, in both groups (p < 0.001); however, in the HT group, at time 1, the majority of women exhibited positive notching [92% (HT) vs 57% (NT), p = 0.013]. CONCLUSIONS: Chronic stage-1 hypertensive women with normal pregnancy outcomes exhibited a progressively increasing postpartum UtA impedance. This trend also occurred in normotensive women, albeit at a significantly lower magnitude.

Uterine artery impedance at very early clinical pregnancy.

OBJECTIVE: The aim of the study was to construct gestational age-based reference ranges for the uterine artery (UtA) mean pulsatility (PI) and resistance (RI) indices from 6 to 10 weeks of pregnancy. METHOD: A prospective, cross-sectional, observational study was carried out in 312 singleton pregnancies with gestational age ranging from 6 to 10 weeks. UtAs were examined transvaginally by color and pulsed Doppler imaging, and the mean of the right and left values of PI and RI, as well as the presence or absence of a bilateral protodiastolic notch, was recorded. UtA-PI and UtA-RI reference percentiles were derived through time-conditional quantile regression. RESULTS: The authors derived the 10th, 50th, and 90th reference percentile curves and correspondent 95% confidence intervals, for the evolution of the UtA mean PI and RI from week 6 to week 10 of gestation. The prevalence of bilateral notching absence was 8.1% (6/74) at 6 weeks and 28.8% (15/52) at 10 weeks. CONCLUSION: The authors present evidence of progressive reduction of uterine vascular impedance in a very early stage of pregnancy and provide new, averaged UtA-PI and UtA-RI charts between 6 and 10 weeks of gestation.

The effects of spinal anaesthesia for elective caesarean section on uterine and umbilical arterial pulsatility indexes in normotensive and chronic hypertensive pregnant women: a prospective, longitudinal study.

BACKGROUND: Despite the known effects of neuraxial blockade on major vessel function and the rapid decrease in uterine vascular impedance, it is unclear how the blockade affects the utero-placental circulation in the near-term. We hypothesize that among women with chronic hypertension, a loss of sympathetic tonus consequent to spinal block may cause significant changes in the utero-placental haemodynamics than the changes typical in normal pregnant women. Therefore, the main study objective was to analyse the effect of spinal anaesthesia for caesarean section on uterine and umbilical arterial impedance in pregnant women at term diagnosed with stage-1 chronic hypertension. METHODS: A prospective, longitudinal study was performed in singleton pregnant women (203 low-risk and 33 with hypertension) scheduled to undergo elective caesarean section. The mean arterial blood pressure and pulsatility indexes for the uterine and umbilical arteries were recorded before and after spinal anaesthesia was performed using 8-9 mg hyperbaric bupivacaine (5 mg/mL) and 2-2.5 µg sufentanil (5 µg/mL). Multiple linear regression models with errors capable of correlation or with unequal variances were fitted using the generalized least squares. RESULTS: In normotensive women, the mean arterial blood pressure decreased after administering spinal anaesthesia (p < 0.05). The pulsatility index of the uterine and umbilical arteries did not change after spinal anaesthesia. In the hypertensive women, the mean arterial blood pressure (p < 0.05) and uterine artery pulsatility index (p < 0.05) decreased. In both groups, the umbilical artery pulsatility index did not change after spinal anaesthesia. CONCLUSIONS: In stage-1 chronic hypertensive pregnant women at term, spinal anaesthesia for caesarean section reduces uterine artery impedance but not umbilical artery impedance.

Foetal aortic flow velocity waveforms in healthy and hypertensive pregnant women.

BACKGROUND: The foetal aortic Doppler frequency spectrum is influenced by cardiac output and contractility of the foetal heart as well as vascular compliance, blood viscosity and impedance of the arterial vascular system. The present study aimed at comparing Doppler flow pulsatility (PI) and resistance (RI) indexes of foetal proximal descending aorta (AoF) in the first, second and third trimesters of pregnancy, in low risk women and in those with chronic arterial hypertension, who had normal pregnancy outcomes. METHODS: A longitudinal and prospective study was carried out in 101 singleton pregnancies (71 low-risk pregnancies and 30 with essential hypertension). Multivariate regression had to be considered due to the experiment's nature: two different indexes were read on the same set of individuals, once at each trimester of the pregnancy [1st (11-14 weeks), 2nd (19-22 weeks) and 3rd (28-32 weeks) trimesters]. The response variable was denoted as index d, in a subject with hypertensive status h (hypertensive or normotensive), at continuous time t. RESULTS: In both groups, AoF-PI and AoF-RI showed a small, but significant increase from the first to the second (1.850 ± 0.339 vs 2.110 ± 0.242 for PI, and 0.829 ± 0.068 vs 0.857 ± 0.038 for RI; p < 0.001) and the first to the third (1.850 ± 0.339 vs 2.163 ± 0.282 for PI, and 0.829 ± 0.068 vs 0.864 ± 0.037 for RI; p < 0.001) trimesters of pregnancy. The global model showed that while AoF-RI trends were converging as time progressed, the AoF-PI values exhibited a divergent trend (p < 0.05). CONCLUSIONS: Chronic stable hypertension in pregnancies with normal outcome, evidences an upward regular trend of foetal descending aorta pulsatility index that is similar to the normotensive condition.

Reference ranges for uterine artery pulsatility index during the menstrual cycle: a cross-sectional study.

BACKGROUND: Cyclic endometrial neoangiogenesis contributes to changes in local vascular patterns and is amenable to non-invasive assessment with Doppler sonography. We hypothesize that the uterine artery (UtA) impedance, measured by its pulsatility index (PI), exhibits a regular pattern during the normal menstrual cycle. Therefore, the main study objective was to derive normative new day-cycle-based reference ranges for the UtA-PI during the entire cycle from days 1 to 34 according to the isolated time effect and potential confounders such as age and parity. METHODS: From January 2009 to December 2012, a cross-sectional study of 1,821 healthy women undergoing routine gynaecological ultrasound was performed. The Doppler flow of the right and left UtA-PI was studied transvaginally by colour and pulsed Doppler imaging. The mean right and left values and the presence or absence of a bilateral protodiastolic notch were recorded. Reference intervals for the PI according to the cycle day were generated by classical linear regression. RESULTS: The majority of patients (97.5%) presented unilateral or bilateral UtA notches. The crude 5th, 50th, and 95th reference percentile curves of the UtA-PI at 1-34 days of the normal menstrual cycle were derived. In all curves, a progressive significant decrease occurred during the first 13 days, followed by an increase and recovery in the UtA-PI. The adjusted 5th, 50th, and 95th reference percentile curves for the effects of age and parity were also obtained. These two conditions generated an approximately identical UtA-PI pattern during the cycle, except with small but significant reductions at the temporal extremes. CONCLUSIONS: The median, 5th, and the 95th percentiles of the UtA-PI decrease during the first third of the menstrual cycle and recover to their initial values during the last two thirds of the cycle. The rates of decrease and recovery depend significantly on age and parity.