Pre-eclampsia in the first pregnancy and subsequent risk of stillbirth in black and white gravidas

Objective

To examine the association between prior pre-eclampsia and subsequent stillbirth in black women and white women.

Study design

This is a population-based retrospective study of Missouri maternally linked birth cohort files from 1989 to 2005. We analyzed singleton first and second births to mothers in the state of Missouri. The study population comprised women who experienced pre-eclampsia in their first pregnancy and a comparison group consisting of women who did not. The two groups were followed to their second pregnancy to document stillbirth occurrence. Adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association between prior pre-eclampsia and subsequent stillbirth were obtained from logistic regression models.

Results

Women who experienced prior pre-eclampsia had a 43% increased risk of subsequent stillbirth [OR = 1.43; 95% CI = 1.08–1.89]. Whereas women with a history of late-onset pre-eclampsia had no elevated risk for subsequent stillbirth, those whose first pregnancy resulted in early-onset pre-eclampsia had a more than 4-fold increased risk of stillbirth in their second pregnancy [OR = 4.07; 95% CI = 2.32–7.14]. When sub-analysis was performed on the two main racial groups in the State, we found that elevated risk for subsequent stillbirth in a second pregnancy was observed among black women with prior early-onset pre-eclampsia (OR = 8.21; 95% CI = 4.03–16.70) but not in whites (OR = 1.95; 95% CI = 0.72–5.26).

Conclusion

Initiation of pregnancy with pre-eclampsia elevates the risk for subsequent stillbirth. The risk elevation is most pronounced in black women with early-onset pre-eclampsia in their first pregnancy. This information is valuable for inter-pregnancy counseling of affected women.     

Extreme parity and the risk of stillbirth

OBJECTIVE: We examined the relationship between extreme parity and risk for stillbirth in the United States. METHODS: Singleton deliveries at 20 weeks of gestation or later in the United States from 1989 through 2000 were analyzed. Risk for stillbirth in women with 1-4 (moderate parity, category I), 5-9 (high parity, category II), 10-14 (very high parity, category III), and 15 or more (extremely high parity, category IV) prior live births were computed using logistic regression. RESULTS: Overall, 27,069,385 births, including 1,206 to extremely high parity mothers, were analyzed. Of the 81,386 stillbirths, 71,623 (2.8/1,000), 9,206 (5.0/1,000), 531 (14.4/1,000), and 26 (21.6/1,000) cases occurred among category I, category II, category III, and category IV gravidas, respectively. With category I as referent category, the odds ratio for stillbirth increased consistently with ascending parity after adjusting for potential confounders: category II (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.02-1.07), category III (OR 1.97, 95% CI 1.81-2.15), and category IV (OR 2.31, 95% CI 1.56-3.42) (P for trend < .001). Among extremely high parity women (category IV), the odds ratio for stillbirth also increased with unit increment in the number of prior live births: 15 (OR 2.72, 95% CI 1.29-5.74), 16 (OR 3.14, 95% CI 1.17-8.41), 17 (OR 6.11, 95% CI 2.56-16.5), and 18 or more prior live births (OR 16.17, 95% CI 8.77-29.82) (P for trend < .001). CONCLUSIONS: The risk for stillbirth is substantially elevated among very high and extremely high parity women, and care providers may consider these groups for targeted periconceptional counseling. Level of Evidence: II-2.     

Maternal obesity and risk of stillbirth: a metaanalysis

We conducted this metaanalysis to summarize the available epidemiologic evidence on the relationship between maternal overweight and obesity and the risk of stillbirth. We identified studies from 3 sources: (1) a PubMed search of relevant articles that were published between January 1980 and September 2005, (2) reference lists of publications that were selected from the PubMed search, and (3) reference lists of review articles on obesity and maternal outcomes that were published between 2000 and 2005. We used a Bayesian random effects model to perform the metaanalysis and metaregression. Nine studies were included in the metaanalysis. The unadjusted odds ratios of a stillbirth were 1.47 (95% CI, 1.08-1.94) and 2.07 (95% CI, 1.59-2.74) among overweight and obese pregnant women, respectively, compared with normal-weight pregnant women. The metaregression analysis found no evidence that these estimates were affected by selected study characteristics. Maternal obesity is associated with an increased risk of stillbirth, although the mechanisms to explain this association are not clear.     

Maternal obesity and stillbirth

The current obesity epidemic appears to contribute significantly to adverse fetal outcomes, and in this work we compile up-to-date evidence for the link between maternal obesity and risk of stillbirth. The review revealed a preponderance of evidence showing that the risk of stillbirth is increased among obese mothers with amplified risk estimates as the severity of obesity increases. Changes in interpregnancy body mass index (BMI) influence subsequent fetal survival and obese women that normalize their BMI values experience enhanced fetal survival in future pregnancies. The elevated risk of stillbirth among obese mothers affect all gestations regardless of fetal number, with the most profound risk (4-fold increase) noted among triplet gestations. The literature has predominantly reported a strong association between maternal prepregnancy obesity and stillbirth. The considerable magnitude of association, consistency of positive results for the association between maternal obesity and stillbirth, the establishment of temporality between maternal obesity and stillbirth, the incremental elevation in risk with ascending BMI values, as well as the improvement in fetal survival with decrease in interpregnancy BMI among obese mothers strongly provide sufficient evidence that the relationship between maternal obesity and stillbirth may be causal.     

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.     

Assessment of risk factors for stillbirth among pregnant women in Jamaica.

A case - control study was conducted to assess the risk factors of stillbirth among pregnant women in Jamaica. A total of 314 women participated (160 with stillborn babies and 154 with live-born babies). A questionnaire designed to collect information on sociodemographic characteristics, antenatal care, medical and sexually transmitted disease (STD) history, method of delivery and infant birth and health status was administered to each woman. Medical records were reviewed to verify medical history. Six variables were found to be significant predictors of stillbirth by multivariate logistic regression. Low birth weight (OR = 4.3, CI = 2.4 - 7.7), complications during pregnancy or delivery (OR = .19, CI = 0.09 - 0.41), method of delivery (caesarean section; OR = 7.2, CI = 1.6 - 33.2), number of living children (OR = 0.54, CI = 0.40 - 0.73), number of antenatal visits (less than three; OR = 2.0, CI = 1.3 - 3.1), and presence of unfavourable and /or adverse fetal outcome (OR = 4.0, CI = 1.8 - 9.2) were found to be associated with stillbirth. These findings have important implications in establishing policies for prenatal care in Jamaica.     

Prospective risk of stillbirth.

Some fraction of any cohort of fetuses alive at a given gestational age will ultimately die before birth. The residual prospective risk of stillbirth as a function of gestational age was calculated from records of the New York City Department of Health covering 370,051 reported births between 1987-1989, including 2454 stillbirths. In the general population, the prospective risk of stillbirth at 26 weeks was one in 150 and, because the time distributions of live births and stillbirths were not proportionate, the risk changed with gestational age. By 40 weeks' gestation, it was one in 475, rising progressively thereafter to one in 375 at 43 weeks. The prospective risk of stillbirth was elevated in certain ethnic groups and increased significantly with advanced maternal age, multiple gestation, and lack of prenatal care. The prospective risk of stillbirth is an important consideration in decisions regarding timing of delivery.     

Differences in cervical cancer mortality among black and white women.

OBJECTIVE: To determine whether stage of disease and treatment patterns account for mortality differences between black and white women with cervical cancer. METHODS: Using data obtained from the Surveillance, Epidemiology, and End Results (SEER) Program for 1988-1994, we determined the associations between race and stage, and race and treatment. Racial differences in survival for up to 7 years of follow-up were adjusted for age, marital status, SEER location, International Federation of Gynecology and Obstetrics (FIGO) stage of disease, lymph node status, grade, histology, and treatment. RESULTS: Cumulative mortality was 36% (366 deaths in 1029 women) for black women and 24% (1215 deaths in 5021 women) for white women; unadjusted hazard ratio was 1.60 (95% confidence interval [CI] 1.43, 1.80). Black women were more likely to present with advanced disease than white women (43.8% compared with 34.8%). In a model adjusting for demographics and FIGO stage, the hazard ratio for black women compared with white women decreased to 1.35 (95% CI 1.19, 1.54). Treatment varied by race, with black women receiving surgery less often (33.5% compared with 48.2%, respectively) and radiation therapy more often (35.3% and 25.2%, respectively) than white women. In a comprehensive model including demographic factors, FIGO stage, other tumor characteristics, and treatment, the adjusted hazard ratio for mortality remained high for black women at 1.30 (95% CI 1.14, 1.48). CONCLUSION: Race remains an independent predictor of cervical cancer survival after accounting for age, stage of disease, treatment patterns, and other factors. Future studies should assess racial differences in clinical severity of disease, comorbidity, and socioeconomic status.     

Young maternal age and risk of intrapartum stillbirth

OBJECTIVES: To determine the risk of intrapartum stillbirth among teen mothers. METHODS: The Missouri maternally linked data containing births from 1978 to 1997 were analyzed. The study group (teen mothers) was sub-divided into younger (<15 years) and older (15-19 years) teenagers. Women aged 20-24 were the referent category. We used Kaplan-Meier product-limit estimator to calculate the cumulative probability of death for each group and the Cox Proportional Hazards Regression models to obtain adjusted hazards ratios. RESULTS: The rate of antepartum and intrapartum stillbirth among teenagers was 3.8 per 1,000 and 1.0 per 1,000, respectively, compared to 3.5 per 1,000 and 0.8 per 1,000 among the reference group. The adjusted risk of intrapartum stillbirth was more than 4 times as high among younger teens (adjusted hazard ratio [AHR] 4.3 [95% CI 4.0-4.7]) and 50% higher among older teens (AHR 1.5 [95% CI 1.2-1.8]). The risk of intrapartum stillbirth occurred in a dose-dependent fashion, with risk increasing as maternal age decreased (P < 0.01). CONCLUSION: Teenagers are at an increased risk of stillbirth, with the greatest risk disparity occurring intrapartum, especially among younger teens. This new information is potentially useful for targeting intervention measures aimed at improving in utero fetal survival among pregnant women at the lower extreme of the maternal age spectrum.     

Prevalence of urinary incontinence symptoms among black,white, and Hispanic women

OBJECTIVE: To compare the prevalence of urinary incontinence symptoms among black, white, and Hispanic women. METHODS: Women attending our gynecologic clinic were asked to complete a survey. The survey asked: "Do you lose urine when you cough, sneeze, lift, jump, or get up from a bed or chair? Do you wear a pad or protective undergarment because you lose urine when you cough, sneeze, lift, jump, or get up from a bed or chair? Do you urinate more than once every hour during the day? Does the urge to urinate wake you from your sleep more than twice most nights? Do you lose urine less than 5 minutes after you feel the urge to urinate more than once per week? RESULTS: Seven hundred ninety-nine black, 932 white, and 639 Hispanic women completed the survey. More white women reported urinary incontinence than did black or Hispanic women (41% versus 31% versus 30%, P <.001) because of their higher prevalence of stress incontinence symptoms (39% versus 27% versus 24%, P <.001). The percentage of women who had urge incontinence symptoms was very similar between the three groups (19% versus 16% versus 16%, P =.214). More black and white women reported mixed incontinence than Hispanic women (14% versus 15% versus 9%, P <.001). More black women had frequency and nocturia than the other two groups (31% and 35% versus 19% and 19% versus 25% and 26%, P <.001). CONCLUSION: The prevalence of incontinence symptoms is significantly different among black, Hispanic, and white women.     

Interpregnancy body mass index changes and risk of stillbirth

Background/Aims: To examine the association between interpregnancy body mass index (BMI) change and stillbirth. Methods: Retrospective study using Missouri maternally linked cohort files (1978-2005). A total of 218,389 women were used in the analysis. BMI was classified as: underweight (<18.5), normal (18.5-24.9), overweight (25-29.9), or obese (≥30.0). Weight change was defined based on BMI category (i.e. normal-normal, normal-obese, etc.). Cox proportional hazard regression models were used to generate adjusted hazard ratios (HR) and 95% CI for the risk of stillbirth in the second pregnancy. Results: Significant findings were associated with interpregnancy BMI changes involving overweight mothers becoming obese (HR = 1.4, 95% CI 1.1-1.7), normal-weight mothers becoming overweight (HR = 1.2, 95% CI 1.0-1.4) or obese (HR = 1.5, 95% CI 1.1-2.1), or obese mothers maintaining their obesity status across the two pregnancies (HR = 1.4, 95% CI 1.2-1.7). Other weight change categories did not show significant risk elevation for stillbirth. Conclusions: BMI change appears to play an important role in subsequent stillbirth risk.     

Effect of the interval between pregnancies on perinatal outcomes among white and black women

OBJECTIVE: We evaluated interpregnancy interval in relation to adverse perinatal outcomes and whether the relationship differed by race. STUDY DESIGN: We analyzed the vital statistics data for multiparous white and black women in Michigan who delivered a singleton live birth during the period 1993 through 1998, using stratified and logistic regression techniques. RESULTS: Among women of both races, the risk for delivering low birth weight, premature, and small-for-gestational-age birth was lowest if the interpregnancy interval was 18 to 23 months. In comparison, among white women, the odds ratios for the 3 outcomes were 1.5, 1.3, and 1.3, respectively, if the interval was <6 months, and 1.9, 1.4, and 1.7, respectively, if the interval was > or =120 months, controlling for other factors. Similarly, among black women, the odds ratios were 1.5, 1.2, and 1.3, respectively, if the interval was <6 months, and 1.6, 1.3, and 1.4, respectively, if the interval was > or =120 months. CONCLUSION: An interpregnancy interval of 18 to 23 months is associated with the lowest risk for adverse perinatal outcomes among both white and black women.     

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.     

Maternal risk factors for cause-specific stillbirth and neonatal death

BACKGROUND: To study specific effects of four maternal risk factors: age, parity, educational level, smoking, for specific causes of stillbirth and neonatal death according to a previously described hierarchic classification. METHODS: The study is based on 9,785 stillbirths or neonatal deaths among infants born in Sweden, 1983-1995 (n=1,412,754) and identified with various Swedish health registers. Statistical analysis is performed using Mantel-Haenszel analysis. RESULTS: Some risk factors, known from the literature, were confirmed and could be quantified. In addition, high parity was shown to increase the risk for death associated with multiple births (OR=2.49, 95% CI 2.07-3.01) and low educational level seems to be protective for such death (OR=0.75, 95% CI 0.60-0.93). If the infant is SGA, the risk for death is higher at high than at low parity (1.70, 95% CI 1.19-2.43, and 1.0, 95% CI 1.06-1.15, respectively). Maternal smoking seems to aggravate the placental abruption because the death risk in the presence of abruption increases when the mother smoked (OR = 1.74, 95% CI 45-2.08). CONCLUSIONS: The study shows that the groups of the classification system used (NICE) differ in their association with known risk factors for stillbirth and neonatal deaths and an analysis based on specific causes of death can therefore unravel risk factors hidden when total mortality is used. The computerized method of classification and the cause-of-death classification developed by us is clearly useful for such analyses which requires large materials.