***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We evaluated the influence of maternal pre-pregnancy body mass index ( BMI ) , based on reported pre-pregnancy weight and height , on blood pressure ( BP ) levels during pregnancy by using information from a prospect i ve cohort of 1733 women recruited before 20 weeks ' gestation . Maternal antenatal BP values were abstract ed from medical records , and we evaluated the mean BP differences according to BMI group in regression models , using generalised estimating equations to account for repeated BP records within each pregnancy . In each trimester , mean systolic BP ( SBP ) and diastolic BP ( DBP ) values were positively associated with maternal pre-gestational BMI . This association persisted after adjustment for maternal age , parity , smoking , education , marital status and physical activity . Overweight women ( 25 - 29 kg/m(2 ) ) had first- , second- and third-trimester mean SBPs that were 8.1 , 7.7 and 8.2 mmHg , respectively , higher than values observed in lean women ( < 20 kg/m(2 ) ) . Mean DBP values were 4.5 , 5.4 and 5.6 mmHg higher for each successive trimester in overweight vs. lean women . Obese ( > 30 kg/m(2 ) ) women consistently had the highest mean SBP and DBP values . Trimester-specific mean SBP values were 10.7 - 12.0 mmHg higher among obese women vs. lean women . Corresponding trimester-specific mean DBP values were 6.9 - 7.4 mmHg higher in obese vs. lean women . Similar patterns were observed when trimester-specific average mean arterial pressures were evaluated . Elevated pregnancy BPs associated with maternal pre-gestational BMI are consistent with a large body of literature that documents increased pre-eclampsia risk among overweight and obese women Objective : To establish the profiles of 24-h non-invasive ambulatory blood pressure measurement ( ABPM ) during the trimesters of pregnancy and the puerperium in normotensive healthy primigravidae Design : A prospect i ve study in which 24-h ABPM was performed on five occasions in each subject : in the first trimester between 9 and 16 weeks ' gestation ; in the second trimester between 18 and 24 weeks ; in the third trimester between 26 and 32 weeks and between 33 and 40 weeks ; and finally at 6 weeks post partum Method : One hundred and six Caucasian primigravid women who were normotensive at their first booking visit were recruited consecutively from the antenatal clinic and had 24-h ABPM  performed with the SpaceLabs 90207 ambulatory system Results : Of the 106 women recruited , 98 completed 24-h ABPM on four of the five measurement occasions . Four women delivered prematurely before 33 weeks ' gestation , thereby missing one ABPM measurement . Changes during pregnancy and the puerperium were assessed against the ABPM performed in the first trimester . There was no difference for daytime or night-time systolic blood pressure between 9 and 33 weeks , but it rose significantly from 33 to 40 weeks . At 6 weeks post partum , systolic blood pressure was not significantly different from the daytime pressure in the first-trimester ABPM but was raised significantly at night . Diastolic blood pressure decreased significantly between 18 and 24 weeks for both daytime and night-time . From 33 to 40 weeks it increased in parallel with systolic blood pressure , and at 6 weeks post partum it was raised significantly compared with first-trimester values for daytime and night-time . The nocturnal fall in blood pressure was preserved throughout pregnancy with a significant difference between daytime and night-time measurements present on all measurement occasions for systolic , diastolic and mean blood pressures and heart rate . There were significant differences between daytime ABPM and clinic blood pressure for both systolic and diastolic blood pressure up to 33 weeks . From 33 weeks until 6 weeks post partum there was no significant difference between daytime ambulatory and clinic blood pressures Conclusion : This study provides reference values for ABPM in healthy primigravidae with generally uncomplicated Objective : To study longitudinally changes in blood pressure ( BP ) and heart rate ( HR )  during healthy pregnancies and to evaluate the influence of parity , pregestational overweight , and excessive weight gain . Methods : A prospect i ve longitudinal cohort study of 57 healthy white women with singleton pregnancies .  BP and HR were measured repeatedly at gestational age 14–16 weeks , 22–24 weeks , 30–32 weeks , 36 weeks , and 6 months postpartum using both an oscillometric measurement device ( Dinamap ) and finger arterial pressure ( Finometer PRO ) . Results : SBP , DBP , and mean arterial pressure ( MAP ) reached a statistically significant trough at gestational age 22–24 weeks using both measurement devices . When compared with the nonpregnant measurement , SBP at gestational age 22–24 weeks was 6.2 mmHg [ 95 % confidence interval ( 95 % CI ) 1.3–11.2 ] lower measured by Finometer and 7.2 mmHg ( 95 % CI 4.2–10.1 ) lower measured by Dinamap  . DBP and MAP were 8.9 mmHg ( 95 % CI 4.6–13.2 ) and 9.8 mmHg ( 95 % CI 5.3–14.2 ) lower measured by Finometer . Measured by Dinamap , DBP and MAP were 4.5 mmHg ( 95 % CI 1.7–7.3 ) and 5.4 mmHg ( 95 % CI 2.8–7.9 ) lower at gestational age 22–24 weeks when compared with the nonpregnant state . SBP was significantly higher in women with pregestational BMI at least 25 kg/m2 with both measurement devices ( both P < 0.05 ) . There were no differences in SBP , DBP , or MAP depending on parity or excessive weight gain . Conclusion : BP measured repeatedly by two different noninvasive devices during pregnancy and postpartum showed a statistically significant drop in mid-pregnancy , followed by a progressive increase until term Background Pregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child . Bioimpedance cardiography may provide additional outcome -relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases . Methods We performed a prospect i ve longitudinal cohort trial in an outpatient setting and included 242 pregnant women .  Cardiac output and concomitant hemodynamic data were recorded from 11th–13th week of gestation every 5th week as well as at two occasions post partum employing bioimpedance cardiography . Results Cardiac output increased during pregnancy and peaked early in the third trimester . A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes . Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy . Furthermore , an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis . Conclusions Cardiovascular adaptation during pregnancy is characterized by distinct pattern described herein . These may be altered in women at risk for preeclampsia or reduced birthweigth . The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks STUDY QUESTION Are there differences in preconception cardiovascular function between women who have a viable pregnancy and those who have a first trimester miscarriage ? SUMMARY ANSWER Preconception cardiovascular function of central haemodynamics and arterial function are similar between women who have a viable pregnancy and those who have a first trimester miscarriage . WHAT IS KNOWN ALREADY Miscarriages have been associated with increased long-term cardiovascular disease risk , and arterial and cardiovascular dysfunction has been hypothesised as the common link . It is not known if these risks are present prior to pregnancy or are a reflection of poor arterial and haemodynamic adaptation to pregnancy . STUDY DESIGN , SIZE , DURATION This prospect i ve longitudinal preconception cohort study was conducted over 18 months . In total , 367 participants were recruited pre-pregnancy , from which 197 pregnancies were recorded ; 39 of these pregnancies ended in first trimester miscarriage . Complete longitudinal data were available for 172 pregnancies ( 140 viable pregnancies , 32 first trimester miscarriages ) from pre-pregnancy to 6 weeks gestation . PARTICIPANTS / MATERIAL S , SETTING , METHODS This was a single site study based at a maternity hospital in London . Healthy women were recruited prior to natural conception and followed up once they became pregnant . All underwent haemodynamic [ cardiac output ( CO ) ,  peripheral vascular resistance  ( PVR ) ]  and arterial function  [ aortic augmentation index ( AIx ) and pulse wave velocity ( PWV ) ] testing prior to pregnancy and at 6 weeks gestation , using non-invasive devices ( gas re-breathing method , Innocor ® and an occilometric device , Vicorder ® ) . Cross-sectional measurements at pre-pregnancy and 6 weeks gestation and a longitudinal analysis of changes were compared between women who had a subsequent viable pregnancy , and those who had a subsequent first trimester miscarriage . MAIN RESULTS AND THE ROLE OF CHANCE There were no differences between women destined to have a healthy ongoing pregnancy compared to those who miscarried , in terms of baseline cardiovascular function , assessed by CO , PVR , PWV or AIx . Similarly , between the groups , there were no differences in pregnancy adaptation with similar trends in cardiovascular function changes from pre-pregnancy to 6 weeks gestation . LIMITATIONS , REASONS FOR CAUTION Whilst this is the first study to investigate preconception and early pregnancy haemodynamic and arterial function in relation to viability , the relatively modest number of miscarriages may not be sufficient to show subtle differences in haemodynamic changes if these were present . WIDER IMPLICATION S OF THE FINDINGS This study suggests that pre-pregnancy haemodynamic and arterial function is unlikely to be the causal link between miscarriages and future cardiovascular disease . Our findings suggests that factors other than the presence of a viable embryo drive cardiovascular changes in early pregnancy . This study raises new questions about miscarriages as an independent risk event which predisposes women to increased cardiovascular risk later in life . STUDY FUNDING /COMPETING INTEREST(S ) The investigators are funded by NIHR Imperial BRC , NIHR Cambridge BRC , Action Medical Research , Imperial College Healthcare Charity and Tommy 's Charity . We acknowledge the loan of ultrasound equipment from Samsung Medison ( South Korea)/MIS Ltd and provision of fertility monitors from SPD Development Company Ltd ( Bedford , UK ) . There are no competing interests . C.C.L. is supported by the UK National Institute for Health Research Biomedical Research Centre based at Imperial College Healthcare National Health Service Trust and Imperial College London . TRIAL REGISTRATION NUMBER Objective : To extend findings that African American women report greater stress during pregnancy , have higher blood pressure ( BP ) , and are twice as likely to have low birthweight infants relative to white women . This study examines a ) racial differences in associations between stress and BP during pregnancy , and b ) the combined effects of stress and BP on infant birthweight in a sample of 170 African American and white women . Methods : A prospect i ve , longitudinal study of pregnant women was conducted in which measures of  BP , stress  , and other relevant variables were collected . Multiple measures of systolic and diastolic BP  were taken at each of three points during pregnancy ( 18–20 , 24–26 , and 30–32 weeks gestation ) . Results : Both systolic blood pressure ( SBP ) and diastolic blood pressure ( DBP ) were positively associated with stress in pregnant African American women and not in pregnant white women . In analyses of birthweight , there were no main effects of BP or stress . However , a significant interaction demonstrated that , when stress was high , DBP was negatively associated with birthweight and a combination of high stress and high DBP predicted the lowest birthweight in the sample . Furthermore , African American women were twice as likely as white women to have a combination of high stress and high DBP . Conclusions : Racial differences in relationships between stress and BP , and the interactive effect of stress and DBP on birthweight together suggest that a high stress-high BP profile may pose a risk for lower birthweight among African American women , in particular , and possibly for all pregnant women . BP = blood pressure ; DBP = diastolic blood pressure ; SBP = systolic blood pressure ; BMI = body mass index ; Ms = means Abstract This article evaluates the association of hepatic , renal , and inflammatory biomarkers with changes in systolic ( SBP ) and diastolic ( DBP ) blood pressure ( BP )  during healthy pregnancies . A prospect i ve cohort study with 225 healthy pregnant women was conducted in Rio de Janeiro , Brazil .  SBP and DBP were evaluated throughout pregnancy ( 5th–13th , 20th–26th , and 30th–36th gestational weeks ) and were the outcomes . The following biomarkers were measured at the first trimester and analyzed according to tertiles of the sample distribution and were considered the main independent predictors : alkaline phosphatase ( ALP ) , alanine aminotransferase ( ALT ) , aspartate aminotransferase ( A 
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Including only higher- quality studies had little effect on findings , with heterogeneity remaining high ( I2 statistic > 50 % ) .
Significant gestational blood pressure and heart rate changes occur that should be taken into account when assessing pregnant women .
Commonly taught substantial decreases in blood pressure mid-pregnancy were not seen and heart rate increases were lower than previously thought .