Maternal blood pressure and fetal growth

Eleven thousand eighty-two term, singleton pregnancies were analyzed for clues to how different levels of maternal blood pressure affect fetal growth. Birth weights progressively increased with increasing pressures until the hypertensive range was reached when maternal edema and proteinuria were absent. Pressure-associated increases in fetal growth were even more rapid when mothers were edematous, and slower when 2+ or greater proteinuria was present. Birth weights leveled off or decreased when pressures reached the hypertensive range. The pressure threshold at which growth slowed increased from diastolic 75 mm Hg in the lowest maternal pregnancy weight gain category to nearly 100 mm Hg in the highest weight gain category. Decreases in birth weight associated with hypertension were most severe when mothers were thin and had low pregnancy weight gains. Diuretics reduced birth weights in low maternal weight gain pregnancies but not in high weight gain ones.     

The risk of unexplained antepartum stillbirth in second pregnancies following caesarean section in the first pregnancy

Objective  To determine if a previous caesarean section increases the risk of unexplained antepartum stillbirth in second pregnancies.
Study design  Retrospective cohort study.
Setting  Large Canadian perinatal database.
Population  158 502 second births.
Methods  Data were obtained from a large perinatal database, which supplied data on demographics, pregnancy complications, maternal medical conditions, previous caesarean section and pregnancy outcomes.
Main outcome measures  Total and unexplained stillbirth.
Results  The antepartum stillbirth rate was 3.0/1000 in the previous caesarean section group compared with 2.7/1000 in the previous vaginal delivery group ( P = 0.46). Multivariate logistic regression modelling, including terms for maternal age (polynomial), weight >91 kg, smoking during pregnancy, pre-pregnancy hypertension and diabetes, did not document an association between previous caesarean section and unexplained antepartum stillbirth (OR 1.27, 95% CI 0.92–1.77).
Conclusion  Caesarean section in the first birth does not increase the risk of unexplained antepartum stillbirth in second pregnancies.     

Pregnancy and severe chronic hypertension: maternal outcome.

OBJECTIVE: To determine the maternal outcome associated with severe chronic hypertension during the second half of pregnancy. METHODS: An analysis of data obtained of women with severe chronic hypertension (> or = 160/110 mm Hg) and > or = 20 weeks' gestation who were hospitalized and delivered during a 5-year period. The pregnancy outcome data were collected retrospectively from medical records. Each patient was observed closely throughout hospitalization with intensive monitoring of the clinical status of both mother and fetus. Antihypertensive drugs were used for systolic or diastolic blood pressure > or = 160 and > or = 110 mm Hg, respectively. Women with superimposed preeclampsia received magnesium sulfate. The main outcome measures were peak of blood pressure, superimposed preeclampsia, and major maternal complications. RESULTS: Of 154 women studied, 111 (72%) had pregestational chronic hypertension, and 120 (78%) developed superimposed preeclampsia. The mean weeks' gestation was 34.5 +/- 4.6. Overall, 110 (71.4%) pregnancies were delivered by cesarean section. Maternal age and parity were significantly higher among women who had pregestational chronic hypertension than those who had chronic hypertension diagnosed during the first half of pregnancy. Abruptio placentae (8.4%), HELLP syndrome (8.4%), acute renal insufficiency (3.9%), pulmonary edema (1.3%), and postpartum hypertensive encephalopathy (1.3%) were the most frequent maternal complications. There were no maternal deaths, disseminated intravascular coagulation, or eclampsia. CONCLUSION: Three-quarters of women with severe chronic hypertension in the second half of pregnancy developed superimposed preeclampsia. Intensive monitoring of the clinical status of the mother was associated with low maternal morbidity and the absence of maternal deaths. Pregestational chronic hypertension does not change the maternal prognosis.     

Birth weight and 24-hour ambulatory blood pressure in nonproteinuric hypertensive pregnancy

OBJECTIVE: The aim of this study was to examine the relationship between maternal ambulatory blood pressure monitor measurements during pregnancy and birth weight in a population of women considered to have hypertension according to conventional antenatal clinic measurement. STUDY DESIGN: A prospective observational study was carried out within the obstetric departments of Leicester Royal Infirmary and Queen Charlotte's Hospital. A total of 237 women were found to have hypertension (blood pressure >/=140/90 mm Hg) without significant proteinuria during examination in the antenatal assessment area. Sequential-day unit blood pressure recordings and a 24-hour automated ambulatory blood pressure recording were performed, and the results were compared with the principal outcome measure of birth weight. RESULTS: A significant inverse association (gradient, -13.5; 95% confidence interval -23.4 to -3.6) was found between daytime ambulatory diastolic blood pressure measurement and birth weight. An increase of 5 mm Hg in daytime mean diastolic blood pressure was associated with a fall in birth weight of 68.5 g. This association remained after adjustment for potential confounders that included maternal age, maternal weight, smoking status, ethnicity, and gestational age at delivery. No such association was found between obstetric day unit assessment of blood pressure and birth weight. CONCLUSION: There is a significant association between blood pressure and birth weight in nonproteinuric hypertensive pregnancies. The best predictor of this association is the daytime mean ambulatory diastolic blood pressure measurement. This is further evidence that maternal blood pressure may be an important confounding and potentially genetic variable in the association between birth weight and subsequent adult hypertension.     

Intrauterine Growth Restriction in Spontaneously Hypertensive Rats

Objective: To determine whether a rise in systolic blood pressure (SBP) ≥ 30 mm Hg and/or diastolic blood pressure (DBP) ≥ 15 mm Hg in the absence of hypertension during pregnancy is associated with adverse pregnancy outcomes. Method: We conducted a retrospective, longitudinal study of 1498 pregnant women without hypertension or proteinuria in the first trimester. The blood pressure levels measured during the first (7.8 ± 2.3 weeks), second (20.7 ± 1.2 weeks), and third trimesters (38.6 ± 1.5 weeks) were analyzed. The perinatal outcome was compared between women who exhibited a rise in SBP ≥ 30 mm Hg and/or DBP ≥ 15 mm Hg during pregnancy (large Δ BP group) and women who did not (small Δ BP group) using one way analysis of variance, chi‐square test, or Fisher's exact test. The contribution of gestational hypertension and a large Δ BP to the development of adverse pregnancy outcomes was evaluated using multivariate logistic regression analysis. Results: Of 1441 women who remained normotensive (SBP < 140 mm Hg and DBP < 90 mm Hg) during pregnancy, 238 (16.5%) and 1203 (83.5%) belonged to the large Δ BP and small Δ BP groups, respectively. There were no significant differences between the two groups in the occurrence rate of gestational proteinuria, preterm deliveries, low‐birth‐weight infants, or small‐for‐gestational age infants. A large Δ BP was not a risk factor in itself for the occurrence of gestational proteinuria or small‐for‐gestational age infants after controlling for the effect of gestational hypertension. Conclusion: A rise in SBP ≥ 30 mm Hg and/or DBP ≥ 15 mm Hg is not a risk factor of adverse outcome among women who remain normotensive during pregnancy.     

Stillbirth and neonatal outcomes in South Australia, 1991-2000

OBJECTIVES: The purpose of this study was to determine the effect of maternal factors associated with impaired placental function on stillbirth and neonatal death rates in South Australia. STUDY DESIGN: From 1991 to 2000, the South Australian Pregnancy Outcome Unit's population database was searched to identify stillbirths and neonatal deaths in women with maternal medical conditions during pregnancy and in twin and singleton pregnancies. RESULTS: Women with hypertension and carbohydrate intolerance and who smoked during pregnancy had an increased risk of stillbirth. Women with twin pregnancies had a significantly higher stillbirth rate than for singletons at each week of gestational age. An increase in stillbirth rate at later gestations was seen with singletons, with a similar trend in twins but rising from 36 weeks' gestation. CONCLUSION: There is a clinical correlation between maternal factors associated with impaired placental function and increased risk of stillbirth, suggesting that intrauterine fetal death represents the mortality end point in a spectrum of intrauterine hypoxia.     

Pregnancy outcome after stillbirth

OBJECTIVE: To assess the subsequent pregnancy outcome in women with previous stillbirth. STUDY DESIGN: The study included all women (n = 54) who delivered a stillbirth between 1997 and 2001 in our department. A control group of women with live birth (n = 108) was matched for delivery within the same year, maternal age (+/- 3 years), parity (+/- 1) and gestational age at delivery (+/- 2 weeks). On February 1, 2004, the charts of these women were examined for subsequent pregnancies. RESULTS: Similar subsequent pregnancy rates were found in women with previous stillbirth and live birth (61.1% and 54.6%), respectively. There were no recurrences of stillbirth; gestational age at delivery, birth weight and Apgar score at 5 minutes were similar to those in the control group, and there was no statistically significant increase in abortion, induction or cesarean section rates. CONCLUSION: There is a favorable outcome in pregnancy following stillbirth. This information is useful for prepregnancy counseling of parents with previous stillbirth.     

Drugs in pregnancy. Antihypertensives.

Fifty per cent of pregnancies are unplanned, and 1-6% of young women have pre-existing hypertension. However, no commonly used antihypertensive agent is known to be teratogenic. ACE inhibitors (and angiotensin-receptor antagonists) should be discontinued due to fetotoxicity. Five to 10% of pregnant women have hypertension, of which pre-existing hypertension is but one type. There is consensus that severe maternal hypertension (blood pressure >or=170/110 mmHg) should be treated to minimize the risk of acute cerebrovascular complications. Parenteral hydralazine may be associated with a higher risk of maternal hypotension, and intravenous labetalol with neonatal bradycardia. There is no consensus that mild-to-moderate hypertension in pregnancy should be treated. Clinical trials indicate that transient severe hypertension, antenatal hospitalization, proteinuria at delivery and neonatal respiratory distress syndrome may be decreased by normalizing blood pressure, but intrauterine fetal growth restriction may be increased. Methodological problems with published trials warrant cautious interpretation of these findings. Methyldopa and beta-blockers have been used most extensively, although atenolol may impair fetal growth in particular and should be avoided.     

Prediction and prevention of recurrent stillbirth

Stillbirth is one of the most common adverse pregnancy outcomes in the United States, occurring in one out of every 200 pregnancies. There is a paucity of information on the outcome of pregnancies after stillbirth. Prior stillbirth is associated with a twofold to 10-fold increased risk of stillbirth in the future pregnancy. The risk depends on the etiology of the prior stillbirth, presence of fetal growth restriction, gestational age of the prior stillbirth, and race. Categorization of the cause of the initial stillbirth will allow better estimates of individual recurrence risk and guide management. A history of stillbirth also increases the risk of other adverse pregnancy outcomes in the subsequent pregnancy such as placental abruption, cesarean delivery, preterm delivery, and low birth weight infants. Prospective studies have revealed an increased risk of stillbirth with low pregnancy-associated plasma protein A, elevated maternal serum alpha fetoprotein, abnormal uterine artery Doppler studies, and antiphospholipid antibodies. However, the positive predictive value of these factors individually is poor. Because fetal growth restriction is associated with almost half of all stillbirths, the correct diagnosis of fetal growth restriction is essential. The use of individualized or customized growth standards will improve prediction of adverse pregnancy outcome by distinguishing growth-restricted fetuses from constitutionally small, healthy fetuses. Antepartum fetal surveillance and fetal movement counting are also mainstays of poststillbirth pregnancy management.     

Pre-pregnancy weight and the risk of stillbirth and neonatal death

OBJECTIVE: To evaluate the association between maternal pre-pregnancy body mass index (BMI) and the risk of stillbirth and neonatal death and to study the causes of death among the children. DESIGN: Cohort study of pregnant women receiving routine antenatal care in Aarhus, Denmark. SETTING: Aarhus University Hospital, Denmark, 1989-1996. POPULATION: A total of 24,505 singleton pregnancies (112 stillbirths, 75 neonatal deaths) were included in the analyses. METHODS: Information on maternal pre-pregnancy weight, height, lifestyle factors and obstetric risk factors were obtained from self-administered questionnaires and hospital files. We classified the population according to pre-pregnancy BMI as underweight (BMI <18.5 kg/m(2)), normal weight (BMI 18.5-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) and obese (BMI 30.0 kg/m(2) or more). MAIN OUTCOME MEASURES: Stillbirth and neonatal death and causes of death. RESULTS: Maternal obesity was associated with a more than doubled risk of stillbirth (odds ratio = 2.8, 95% confidence interval [CI]: 1.5-5.3) and neonatal death (odds ratio = 2.6, 95% CI: 1.2-5.8) compared with women of normal weight. No statistically significantly increased risk of stillbirth or neonatal death was found among underweight or overweight women. Adjustment for maternal cigarette smoking, alcohol and caffeine intake, maternal age, height, parity, gender of the child, years of schooling, working status and cohabitation with partner did not change the conclusions, nor did exclusion of women with hypertensive disorders or diabetes mellitus. No single cause of death explained the higher mortality in children of obese women, but more stillbirths were caused by unexplained intrauterine death and fetoplacental dysfunction among obese women compared with normal weight women. CONCLUSION: Maternal obesity more than doubled the risk of stillbirth and neonatal death in our study. The present and other studies linking maternal obesity to an increased risk of severe adverse pregnancy outcomes emphasise the need for public interventions to prevent obesity in young women.     

Resolution of hypertension during pregnancy in familial hyperkalemia and hypertension with the WNK4 Q565E mutation

OBJECTIVE: Secondary hypertension during pregnancy usually carries high maternal and fetal morbidity and mortality rates. A rare form of monogenic hypertension is familial hyperkalemia and hypertension, which is caused by mutations in the kinases WNK1 or WNK4 and other unknown molecular defects. The purpose of the study was to examine the course of pregnancy in hypertensive women with familial hyperkalemia and hypertension. STUDY DESIGN: We prospectively studied 2 pregnancies of a woman with familial hyperkalemia and hypertension and the Q565E WNK4 mutation (pregnancies 1 and 2) and retrospectively studied the course of 2 pregnancies in another woman who was an affected member of this largest family described in the literature. RESULTS: Both women had hypertension (170-190/105-110 mm Hg), hyperkalemia (5.3-6.0 mmol/L), and hypercalciuria, all of which were well controlled by thiazides. During pregnancies, thiazides were discontinued; throughout the pregnancy, the blood pressure remained normal at 120 to 130/75 to 85 mm Hg; however, hyperkalemia and hypercalciuria, which were documented in pregnancies 1 and 2, persisted. Renin and aldosterone levels (which were measured in pregnancies 1 and 2) rose towards their end. Four normal infants were born. A woman with familial hyperkalemia and hypertension of unknown molecular defect who had 2 pregnancies with hypertension exacerbation and premature deliveries was described previously. CONCLUSION: In familial hyperkalemia and hypertension with the WNK4 mutation, pregnancy ameliorates hypertension; however, hyperkalemia and hypercalciuria persist. This dissociation may shed light on the pathogenesis of familial hyperkalemia and hypertension, on pregnancy-related hypertension, and on the mechanism of action of WNK4 kinase, a major regulator of cellular ion transport.     

Thrombophilic risk factors for placental stillbirth

Objectives

To define the characteristics of placental stillbirth and the possible contribution of thrombophilic risk factors.

Study design

A prospective cohort study was performed. Women diagnosed with antenatal stillbirth (>20 weeks) of singleton pregnancies between 2006 and 2008 were referred postpartum for evaluation. Maternal risk factors, fetal, placental and cord abnormalities, and a detailed thrombophilia screening, including inherited and acquired thrombophilia, were evaluated. Fetal autopsy and placental pathology were encouraged.Placental stillbirth was defined as death of a normally-formed fetus with evidence of intrauterine fetal growth restriction, oligohydramnios, placental abruption and/or histological evidence of placental contribution to fetal death. Pregnancy characteristics and thrombophilia profiles were compared between placental and non-placental stillbirth cases.

Results

Sixty-seven women with stillbirth comprised the study group. Placental stillbirth was evident in 33/67 (49.3%). Significantly more women with placental stillbirth were nulliparous, when compared with non-placental stillbirth women (21/33 vs. 9/34, p = 0.002). Mean gestational age was lower for placental, compared with non-placental stillbirth (31.1 ± 6.1 weeks vs. 33.9 ± 4.8 weeks, p = 0.04), as was birth weight. Thirty-six of the 67 women (53.7%) tested positive for at least one thrombophilia. The prevalence of maternal thrombophilia was higher for placental stillbirth women (63.6%), and even higher (69.6%) for women after preterm (<37 weeks) placental stillbirth. Factor V Leiden and/or prothrombin G20210A mutation were much more prevalent in placental versus non-placental stillbirth women (OR 3.06, 95% CI 1.07-8.7).

Conclusions

Placental stillbirth comprises a unique subgroup with specific maternal characteristics. Maternal thrombophilia is highly prevalent, especially in preterm placental stillbirth. This may have implications for the management strategy in future pregnancies in this subgroup.     

Maternal blood pressures during pregnancy and the risk of delivering a small-for-gestational-age neonate

Objective: To determine the relationship between maternal blood pressures throughout pregnancy and the risk of delivering a small-for-gestational-age (SGA) neonate. Methods: Women were prospectively enrolled at 9–14 weeks and had serial blood pressure measurements throughout pregnancy. SGA prevalence was compared to maternal blood pressure at enrollment, average blood pressure during each trimester, and blood pressure trends throughout gestation. Blood pressure was categorized as normotension, prehypertension, or hypertension using Joint National Committee on Hypertension-7 (JNC-7) definitions. Information on preeclampsia prevalence was also obtained due to its frequent concurrence with SGA. Results: A total of 758 women had 8438 blood pressure measurements taken (average 11.1, range 3–14) and 65 (8.6%) delivered an SGA neonate. Forty-two of 514 (8.2%) normotensive women at enrollment and 23/244 (9.4%) women with enrollment prehypertension or hypertension delivered an SGA neonate. Women with persistent hypertensive range blood pressures had an SGA rate 2–3 times higher than other women (p = 0.272) as well as a significantly higher preeclampsia rate (p < 0.001). Women with elevated enrollment blood pressures did not have an increased SGA rate if their blood pressures improved throughout pregnancy. Logistic regression identified enrollment uterine artery Doppler, pregnancy-associated plasma protein-A levels, and ethnicity as primary contributors to SGA. Conclusion: Blood pressure improvement throughout pregnancy decreases the preeclampsia rate without increasing SGA frequency. Theoretical risks of fetal growth delay should not prevent investigations into improved maternal blood pressure control, possibly at thresholds lower than commonly used in obstetric practice, beginning in the first trimester of pregnancy.     

Antihypertensives

Fifty per cent of pregnancies are unplanned, and 1—6% of young women have pre-existing hypertension. However, no commonly used antihypertensive agent is known to be teratogenic. ACE inhibitors (and angiotensin-receptor antagonists) should be discontinued due to fetotoxicity.Five to 10% of pregnant women have hypertension, of which pre-existing hypertension is but one type. There is consensus that severe maternal hypertension (blood pressure →170/110 mmHg) should be treated to minimize the risk of acute cerebrovascular complications. Parenteral hydralazine may be associated with a higher risk of maternal hypotension, and intravenous labetalol with neonatal bradycardia. There is no consensus that mild-to-moderate hypertension in pregnancy should be treated. Clinical trials indicate that transient severe hypertension, antenatal hospitalization, proteinuria at delivery and neonatal respiratory distress syndrome may be decreased by normalizing blood pressure, but intrauterine fetal growth restriction may be increased. Methodological problems with published trials warrant cautious interpretation of these findings. Methyldopa and β-blockers have been used most extensively, although atenolol may impair fetal growth in particular and should be avoided.     

Severe hypertension in pregnancy: hydralazine or labetalol. A randomized clinical trial

OBJECTIVE: The objective was to compare the safety and efficacy of intravenous labetalol and intravenous hydralazine for acutely lowering blood pressure in pregnancy. STUDY DESIGN: Two hundred women with severe hypertension in pregnancy were randomized to receive hydralazine (5 mg as a slow bolus dose given intravenously, and repeated every 20 min up to a maximum of five doses) or labetalol (20-mg intravenous bolus dose followed by 40 mg if not effective within 20 min, followed by 80 mg every 20 min up to a maximum dose of 300 mg). The primary end point was successful lowering of blood pressure and maternal hypotension. RESULTS: Women were similar with respect to characteristics at randomization. No significant differences were observed for maternal hypotension or persistent severe hypertension; only two patients in the hydralazine group presented with hypotension. Palpitations (p=0.01) and maternal tachycardia (p=0.05) occurred significantly more often in patients treated with hydralazine. The main neonatal outcomes were very similar per group; however, hypotension and bradycardia were significantly more frequent in the labetalol group. There were two neonatal deaths per antihypertensive drug group. CONCLUSIONS: This randomized clinical trial shows that labetalol and hydralazine fulfill the criteria required for an antihypertensive drug to treat severe hypertension in pregnancy.     

LONG-TERM PROGNOSIS OF HYPERTENSION IN PREGNANCY

Objectives To assess the prevalence of subsequent hypertension in women with hypertensive pregnancies and evaluate it according to the subclassifications of hypertension in pregnancy.

Methods A survey was carried out in 476 women with hypertensive pregnancies (cases) and 226 normotensive controls delivered between 1973 and 1991 in a tertiary-level teaching hospital. They were invited to participate by mail and 273 cases (57%) and 86 controls (38%) completed the analysis. Outcomes assessed were prevalences of hypertension, diabetes, and hypercholesterolemia, together with cardiovascular morbidity.

Results Among responders, age and parity were similar in both groups although follow-up time was longer in controls. Subsequent hypertension was more frequent within cases. After excluding chronic and unclassifiable hypertension, the mean blood pressure was higher in all other forms of pregnancy hypertension (103 ± 13 mm Hg versus 94 ± 13 mm Hg, p < 0.001); long-term hypertension prevalence was 45% in cases and 14% in controls [odds ratio (OR) = 5.1; 95% confidence interval (95% CI) = 2.5–9.8; p < 0.001]. There were no differences with respect to the prevalences of subsequent diabetes or hypercholesterolemia. Remote hypertension was more common following gestational hypertension (54%) than in preeclampsia (38%), eclampsia (14%), or normotensive cases (14%) (OR for gestational hypertension versus normotensives = 7.2; 95% CI = 3.4–14.8, p < 0.001, and OR for preeclampsia versus normotensives = 3.7; 95% CI = 1.7–7.9, p < 0.001).

Conclusions After an average of 13.6 years since the index pregnancy, women with hypertensive pregnancies have an increased risk of subsequent hypertension. Gestational hypertension is the hypertensive disorder of pregnancy with the highest incidence of subsequent hypertension. Women with preeclampsia have a greater tendency to develop hypertension than women with normotensive pregnancies. By contrast, women with eclampsia do not.

     

The usefulness of uterine artery doppler velocimetry in high risk pregnancy diagnostic (PIH and/or IUGR)

OBJECTIVES: High risk pregnancy was defined as developing of pregnancy induced hypertension or/and growth retardation in the course of gestation. DESIGN: The main aim of the study is to analyze the usefulness of uterine artery doppler velocimetry in high risk pregnancy diagnostic. MATERIALS AND METHODS: 610 single pregnancies were included in the study. First group of normal pregnancies where -530 single normal pregnancies between 19 and 39 gestation weeks. S/D, RI & PI in both uterine arteries were assessed. There were assessed flow velocity waveforms also for detection of notches. At the next stage an examined group with 80 pregnant women was formed where in the course of gestation pregnancy induced hypertension and/or fetal growth retardation. 24 hour monitoring of the blood pressure in the examined group was performed. Obtained data from both groups was calculated and statistically analyzed. RESULTS: Mean values for flow velocity waveform indices were estimated for both groups: controls S/D 2,35 (SD 0,61), RI 0,56 (SD 0,11), PI 0,96 (SD 0,32), examined group S/D 2,99 (SD 1,16), RI 0,63 (SD 0,12), PI 1,26 (SD 0,51). There is significant difference between values for all flow parameters p < 0,001. In the control group we observed notches in 11,8% of all women and in the examined (hypertension and/or growth restriction) group in 81,3% (p<0,001). The sensitivity is 81,3% and specificity 88,2%. MoMRIs for both uterine arteries were calculated to compare data from control and examined group. In the examined group 41,3% RI results were above calculated MoM and there is significant difference between both groups (p <0,001). The sensitivity is 41,3% and specificity 89,5%. In the group of the hypertensive pregnant women where mean systolic blood pressure in 24 hour monitoring was above 130 mm Hg we observed notches in 61,1% of flow velocity waveforms in uterine arteries. In the group of normal pregnancies there were 11,8% notches and there is significant difference between both groups (p<0,001). CONCLUSIONS: The uterine artery velocimetry values of S/D, RI, PI decrease with the progression of gestation. There are no significant differences between right and left uterine artery doppler velocimetry. There are significant differences for values and percentage of notches in both groups. Extremely high rate of notches is observed in the group with most elevated blood pressure (daily mean value over 130mm Hg). It is possible to calculate obstetrical risk assessing values for blood flow in uterine arteries in pregnancy. It can be helpful to estimate methods detecting elevated risk for hypertension and/or growth retardation in pregnancy.     

The influence of pregnancy on arterial compliance

OBJECTIVE: To examine the effect of pregnancy and the interval between pregnancies on arterial compliance as measured by mean arterial pressure (MAP) and pulse pressure. METHODS: We conducted a 3-month chart review of deliveries at a tertiary care hospital (index pregnancies). Data collected included demographics, obstetric history, blood pressures, prepregnancy weight, weight gain, and neonatal outcome. If a subject's first delivery occurred at our institution, these records were reviewed in a similar fashion. Mean antepartum MAP and pulse pressure were calculated and compared for each trimester between index and first pregnancies. Statistical methods employed included repeated measures analysis of variance, repeated measures analysis of covariance, and correlation analysis. RESULTS: Two hundred eighty-five charts were reviewed. Forty-seven women had complete data covering both index and first pregnancy. Mean arterial pressure was significantly higher in all trimesters of first compared with index pregnancies (first pregnancy-first trimester 82.0 +/- 8.1 mm Hg, index pregnancy-first trimester 79.4 +/- 7.6 mm Hg, P = .032; first-second trimester 81.6 +/- 6.7 mm Hg, index-second trimester 78.7 +/- 6.6 mm Hg, P = .016; first-third trimester 83.9 +/- 6.9 mm Hg, index-third trimester 81.6 +/- 6.9 mm Hg, P = .047). Repeated measures analysis of covariance confirmed that pregnancy order contributed independently to differences in MAP. The interval between pregnancies was found to be inversely related to the difference in MAP from first to index pregnancies by trimester (r = -0.41, P = .004) and the change in MAP within pregnancy from first to third trimester (r = -0.31, P = .046). CONCLUSION: Mean arterial pressure is reduced in subsequent pregnancies compared with first pregnancies. This raises the possibility that pregnancy plays a role in modifying cardiovascular compliance. Consistent with this, the effect has temporal limitations in that the shorter the interval between pregnancies, the greater the reduction in MAP.     

The risk of intrapartum stillbirth among smokers of advanced maternal age

BACKGROUND/AIM: The effects of advanced maternal age and smoking in pregnancy on fetal survival have previously been reported. However, whether advanced maternal age modifies the relationship between smoking in pregnancy and intrapartum stillbirth remains unknown. We therefore set out to determine the impact of advanced maternal age (> or =35 years) on the association between smoking during pregnancy and intrapartum stillbirth by employing retrospective analysis of birth registry data. METHODS: We used a cohort of singleton births in Missouri from 1978 through 1997 (N = 1,436,628) to compute the risk of total, antepartum, and intrapartum stillbirth in smoking mothers. We categorized mothers into two age groups: "younger" (<35 years), and "older" (> or =35 years). Non-smoking mothers age <35 years were the referent category. Cox regression models were used to generate independent measures of association between intrauterine tobacco exposure and the risk of total, antepartum, and intrapartum stillbirth in each age group. RESULTS: A total of 5,772 counts of stillbirth were identified, yielding a stillbirth rate of 4.0 per 1,000. Approximately 33% (N = 1,900) occurred among older smokers resulting in a stillbirth rate of 9.1 per 1,000. The probability of intrapartum stillbirth was greatest among older smokers, followed by younger smokers and lowest among younger non-smokers (P < 0.01). As compared to non-smoking younger gravidas, younger smoking mothers had a 30% greater likelihood for both antepartum and intrapartum stillbirth (adjusted hazard ratio [95% confidence interval]: 1.3 [1.2-1.4] and 1.3 [1.2-1.5], respectively). Among older smokers the risk for intrapartum stillbirth was three times that of the referent group (adjusted hazard ratio: 3.2, 95% confidence interval: 2.2-4.5). CONCLUSIONS: The risk of intrapartum stillbirth associated with smoking in pregnancy is potentiated by the age of the mother. This information will help policy makers develop targeted smoking cessation campaigns and positively impact quit rates in older mothers.