Pregnancy Complications and the Risk of Metabolic Syndrome for the Offspring

Metabolic syndrome is a growing problem globally, and is a contributor to non-communicable diseases such as type II diabetes and cardiovascular disease. The risk of developing specific components of the metabolic syndrome such as obesity, hyperlipidemia, hypertension, and elevated fasting blood sugar has been largely attributed to environmental stressors including poor nutrition, lack of exercise, and smoking. However, large epidemiologic cohorts and experimental animal models support the "developmental origins of adult disease" hypothesis, which posits that a significant portion of the risk for adult metabolic conditions is determined by exposures occurring in the perinatal period. Maternal obesity and the rate of complications during pregnancy such as preterm birth, preeclampsia, and gestational diabetes continue to rise. As our ability to reduce perinatal morbidity and mortality improves the long-term metabolic consequences remain uncertain, pointing to the need for further research in this area.

Cervical surgery for cervical intraepithelial neoplasia and prolonged time to conception of a live birth: a case-control study

OBJECTIVE

To determine whether women with a history of surgery for cervical intraepithelial neoplasia (CIN) are at an increased risk of subfertility, measured as a time to pregnancy of more than 12 months.

DESIGN

Case-control study.

SETTING

Iowa Health in Pregnancy Study (IHIPS), a population-based case-control study of preterm and small-for-gestational-age (SGA) live birth outcomes (from May 2002 through June 2005) in the USA.

SAMPLE

Women with an intended pregnancy and a history of either one prior cervical surgery (n = 152), colposcopy only (n = 151), or no prior cervical surgery or colposcopy (n = 1021).

METHODS

Cervical treatment history, pregnancy intention, time to pregnancy, and other variables were self-reported by computer-assisted telephone interviews. Odds ratios were calculated using logistic regression to estimate the risk of prolonged time to pregnancy among women with a history of cervical surgery or colposcopy alone, compared with untreated women (control group).

MAIN OUTCOME MEASURE

Prolonged time to pregnancy (i.e. >1 year).

RESULTS

Prolonged time to pregnancy was most prevalent among treated women (16.4%), compared with untreated women (8.4%) and women with colposcopy only (8.6%) (P = 0.039). After adjusting for covariates, women with prior cervical surgery had a more than two-fold higher risk of prolonged time to pregnancy compared with untreated women (aOR 2.09, 95% CI 1.26-3.46). In contrast, women with a history of colposcopy only had a risk equivalent to that found among untreated women (aOR 1.02, 95% CI 0.56-1.89).

CONCLUSIONS

Women with a history of cervical treatment for CIN are at increased risk of subfertility, measured as a time to pregnancy of more than 12 months.

Correction of systematic bias in ultrasound dating in studies of small-for-gestational-age birth: an example from the Iowa Health in Pregnancy Study

The authors examined whether early ultrasound dating (≤20 weeks) of gestational age (GA) in small-for-gestational-age (SGA) fetuses may underestimate gestational duration and therefore the incidence of SGA birth. Within a population-based case-control study (May 2002-June 2005) of Iowa SGA births and preterm deliveries identified from birth records (n = 2,709), the authors illustrate a novel methodological approach with which to assess and correct for systematic underestimation of GA by early ultrasound in women with suspected SGA fetuses. After restricting the analysis to subjects with first-trimester prenatal care, a nonmissing date of the last menstrual period (LMP), and early ultrasound (n = 1,135), SGA subjects' ultrasound GA was 5.5 days less than their LMP GA, on average. Multivariable linear regression was conducted to determine the extent to which ultrasound GA predicted LMP dating and to correct for systematic misclassification that results after applying standard guidelines to adjudicate differences in these measures. In the unadjusted model, SGA subjects required a correction of +1.5 weeks to the ultrasound estimate. With adjustment for maternal age, smoking, and first-trimester vaginal bleeding, standard guidelines for adjudicating differences in ultrasound and LMP dating underestimated SGA birth by 12.9% and overestimated preterm delivery by 8.7%. This methodological approach can be applied by researchers using different study populations in similar research contexts.

Genome-wide association study identifies a maternal copy-number deletion in PSG11 enriched among preeclampsia patients

Background

Specific genetic contributions for preeclampsia (PE) are currently unknown. This genome-wide association study (GWAS) aims to identify maternal single nucleotide polymorphisms (SNPs) and copy-number variants (CNVs) involved in the etiology of PE.

Methods

A genome-wide scan was performed on 177 PE cases (diagnosed according to National Heart, Lung and Blood Institute guidelines) and 116 normotensive controls. White female study subjects from Iowa were genotyped on Affymetrix SNP 6.0 microarrays. CNV calls made using a combination of four detection algorithms (Birdseye, Canary, PennCNV, and QuantiSNP) were merged using CNVision and screened with stringent prioritization criteria. Due to limited DNA quantities and the deleterious nature of copy-number deletions, it was decided a priori that only deletions would be selected for assay on the entire case-control dataset using quantitative real-time PCR.

Results

The top four SNP candidates had an allelic or genotypic p-value between 10^-5 and 10^-6, however, none surpassed the Bonferroni-corrected significance threshold. Three recurrent rare deletions meeting prioritization criteria detected in multiple cases were selected for targeted genotyping. A locus of particular interest was found showing an enrichment of case deletions in 19q13.31 (5/169 cases and 1/114 controls), which encompasses the PSG11 gene contiguous to a highly plastic genomic region. All algorithm calls for these regions were assay confirmed.

Conclusions

CNVs may confer risk for PE and represent interesting regions that warrant further investigation. Top SNP candidates identified from the GWAS, although not genome-wide significant, may be useful to inform future studies in PE genetics.

Association of seasonality with hypertension in pregnancy: a systematic review

A systematic literature review was conducted to examine all academic, peer-reviewed studies of seasonal or monthly variation in the prevalence of gestational hypertension, preeclampsia, or eclampsia. The objective was to test the hypothesis that prevalence rates are highest during the winter months in non-tropical regions and during wet or humid periods in tropical climates. The authors searched the epidemiological literature indexed in PubMed, cross-referenced bibliographic materials, and reviewed personal archives. Of 60 abstracts and articles screened, 20 met the final inclusion criteria. Studies included were published between 1938 and 2010. Despite differences in setting, data sources, study design, outcome definitions, and control of known risk factors, 16 separate studies (11 non-tropical and 5 tropical) concurred that prevalence rates were higher for winter delivery in non-tropical regions or delivery during wet or humid periods in tropical climates. Although the reasons for these patterns are unknown, seasonal variation in infectious diseases, environmental triggers of asthma, vitamin D levels, physiological responses to cold temperatures, healthcare access, and nutritional intake may all play a role.

A probabilistic sampling method (PSM) for estimating geographic distance to health services when only the region of residence is known

Background

The need to estimate the distance from an individual to a service provider is common in public health research. However, estimated distances are often imprecise and, we suspect, biased due to a lack of specific residential location data. In many cases, to protect subject confidentiality, data sets contain only a ZIP Code or a county.

Results

This paper describes an algorithm, known as "the probabilistic sampling method" (PSM), which was used to create a distribution of estimated distances to a health facility for a person whose region of residence was known, but for which demographic details and centroids were known for smaller areas within the region. From this distribution, the median distance is the most likely distance to the facility. The algorithm, using Monte Carlo sampling methods, drew a probabilistic sample of all the smaller areas (Census blocks) within each participant's reported region (ZIP Code), weighting these areas by the number of residents in the same age group as the participant. To test the PSM, we used data from a large cross-sectional study that screened women at a clinic for intimate partner violence (IPV). We had data on each woman's age and ZIP Code, but no precise residential address. We used the PSM to select a sample of census blocks, then calculated network distances from each census block's centroid to the closest IPV facility, resulting in a distribution of distances from these locations to the geocoded locations of known IPV services. We selected the median distance as the most likely distance traveled and computed confidence intervals that describe the shortest and longest distance within which any given percent of the distance estimates lie. We compared our results to those obtained using two other geocoding approaches. We show that one method overestimated the most likely distance and the other underestimated it. Neither of the alternative methods produced confidence intervals for the distance estimates. The algorithm was implemented in R code.

Conclusions

The PSM has a number of benefits over traditional geocoding approaches. This methodology improves the precision of estimates of geographic access to services when complete residential address information is unavailable and, by computing the expected distribution of possible distances for any respondent and associated distance confidence limits, sensitivity analyses on distance access measures are possible. Faulty or imprecise distance measures may compromise decisions about service location and misdirect scarce resources.

Does chocolate intake during pregnancy reduce the risks of preeclampsia and gestational hypertension?

PURPOSE

Chocolate consumption is associated with favorable levels of blood pressure and other cardiovascular disease risk markers. We analyzed a prospective cohort study to determine whether regular chocolate intake during pregnancy is associated with reduced risks of preeclampsia and gestational hypertension (GH).

METHODS

Subjects were recruited from 13 prenatal care practices in Connecticut (1988-1991). In-person interviews were administered at <16 weeks' gestation to ascertain risk factors for adverse pregnancy outcomes. Hospital delivery and prenatal records were abstracted to classify preeclampsia (n = 58), GH (n = 158), and normotensive pregnancies (n = 2351). Chocolate consumption (servings/week) during the first and third trimesters was ascertained at initial interview and immediately postpartum, respectively. Consumers of less than 1 serving/week comprised the referent group. Adjusted odds ratios (aORs) were estimated by the use of logistic regression.

RESULTS

Chocolate intake was more frequent among normotensive (80.7%) than preeclamptic (62.5%) or GH women (75.8%), and associated with reduced odds of preeclampsia (first trimester: aOR, 0.55; 95% confidence interval [95% CI], 0.32-0.95; third trimester: aOR, 0.56; 95% CI, 0.32-0.97). Only first trimester intake was associated with reduced odds of GH (aOR,0.65; 95% CI, 0.45-0.87).

CONCLUSIONS

These findings provide additional evidence of the benefits of chocolate. Prospective studies are needed to confirm and delineate protective effects of chocolate intake on risk of preeclampsia.

Trends in Clostridium difficile infection among peripartum women

With use of the Nationwide Inpatient Sample, we conducted a study to determine whether rates of Clostridium difficile infection for delivery-associated hospitalizations are increasing. From 1998 to 2006, the number and incidence of C. difficile infection among peripartum women increased significantly. These increases were comparable to those observed in the general hospitalized population.

Prevalence of intimate partner violence among an abortion clinic population

In this cross-sectional, clinic-based study, we estimated 1-year prevalence of intimate partner violence among 986 patients who had elective abortions. We assessed physical, sexual, and battering intimate partner violence via self-administered, computer-based questionnaires. Overall, physical and sexual intimate partner violence prevalence was 9.9% and 2.5%, respectively; 8.4% of those in a current relationship reported battering. Former partners perpetrated more physical and sexual assaults than did current partners. Violence severity increased with frequency. Abortion patients experience high intimate partner violence rates, indicating the need for targeted screening and community-based referral.

National Institutes of Health State-of-the-Science Conference statement: Diagnosis and Management of Ductal Carcinoma In Situ September 22-24, 2009

OBJECTIVE

To provide health-care providers, patients, and the general public with a responsible assessment of currently available data on the diagnosis and management of ductal carcinoma in situ (DCIS).

PARTICIPANTS

A non-Department of Health and Human Services, nonadvocate, 14-member panel representing the fields of oncology, radiology, surgery (general and reconstructive), pathology, radiation oncology, internal medicine, epidemiology, biostatistics, nursing, obstetrics and gynecology, preventative medicine and population health, and social work. In addition, 22 experts from pertinent fields presented data to the panel and conference audience.

EVIDENCE

Presentations by experts and a systematic review of the literature prepared by the Minnesota Evidence-based Practice Center, through the Agency for Healthcare Research and Quality. Scientific evidence was given precedence over anecdotal experience.

CONFERENCE PROCESS

The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was presented on the final day of the conference and circulated to the audience for comment. The panel released a revised statement later that day at http://consensus.nih.gov. This statement is an independent report of the panel and is not a policy statement of the National Institutes of Health or the Federal Government.

CONCLUSIONS

Clearly, the diagnosis and management of DCIS is highly complex with many unanswered questions, including the fundamental natural history of untreated disease. Because of the noninvasive nature of DCIS, coupled with its favorable prognosis, strong consideration should be given to elimination of the use of the anxiety-producing term "carcinoma" from the description of DCIS. The outcomes in women treated with available therapies are excellent. Thus, the primary question for future research must focus on the accurate identification of patient subsets diagnosed with DCIS, including those persons who may be managed with less therapeutic intervention without sacrificing the excellent outcomes presently achieved. Essential in this quest will be the development and validation of accurate risk stratification methods based on a comprehensive understanding of the clinical, pathological, and biological factors associated with DCIS.

NIH state-of-the-science conference statement: diagnosis and management of ductal carcinoma in situ (DCIS)

OBJECTIVE

To provide health care providers, patients, and the general public with a responsible assessment of currently available data on the diagnosis and management of ductal carcinoma in situ (DCIS).

PARTICIPANTS

An non-DHHS, nonadvocate 14-member panel representing the fields of fields of oncology, radiology, surgery (general and reconstructive), pathology, radiation oncology, internal medicine, epidemiology, biostatistics, nursing, obstetrics and gynecology, preventative medicine and population health, and social work. In addition, 22 experts from pertinent fields presented data to the panel and conference audience.

EVIDENCE

Presentations by experts and a systematic review of the literature prepared by the Minnesota Evidence-based Practice Center, through the Agency for Healthcare Research and Quality. Scientific evidence was given precedence over anecdotal experience.

CONFERENCE PROCESS

The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was presented on the final day of the conference and circulated to the audience for comment. The panel released a revised statement later that day at http://consensus.nih.gov. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government.

CONCLUSIONS

The diagnosis and management of DCIS is highly complex with many unanswered questions, including the fundamental natural history of untreated disease. Because of the noninvasive nature of DCIS, coupled with its favorable prognosis, strong consideration should be given to remove the anxiety-producing term "carcinoma" from the description of DCIS. The outcomes in women treated with available therapies are excellent. Thus, the primary question for future research must focus on the accurate identification of patient subsets diagnosed with DCIS, including those persons who may be managed with less therapeutic intervention without sacrificing the excellent outcomes presently achieved. Essential in this quest will be the development and validation of accurate risk stratification methods based on a comprehensive understanding of the clinical, radiological, pathological, and biological factors associated with DCIS.

Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence

Prenatal maternal stress (PNMS) has been linked with adverse health outcomes in the offspring through experimental studies using animal models and epidemiological studies of human populations. The purpose of this review article is to establish a parallel between animal and human studies, while focusing on methodological issues and gaps in knowledge. The review examines the quality of recent evidence for prevailing PNMS theoretical models, namely the biopsychosocial model for adverse pregnancy outcomes and the fetal programming model for chronic diseases. The investigators used PubMed (2000-06) to identify recently published original articles in the English language literature. A total of 103 (60 human and 43 animal) studies were examined. Most human studies originated from developed countries, thus limiting generalisability to developing nations. Most animal studies were conducted on non-primates, rendering extrapolation of findings to pregnant women less straightforward. PNMS definition and measurement were heterogeneous across studies examining similar research questions, thus precluding the conduct of meta-analyses. In human studies, physical health outcomes were often restricted to birth complications while mental health outcomes included postnatal developmental disorders and psychiatric conditions in children, adolescents and adults. Diverse health outcomes were considered in animal studies, some being useful models for depression, schizophrenia or attention deficit hyperactivity disorder in human populations. The overall evidence is consistent with independent effects of PNMS on perinatal and postnatal outcomes. Intervention studies and large population-based cohort studies combining repeated multi-dimensional and standardised PNMS measurements with biomarkers of stress are needed to further understand PNMS aetiology and pathophysiology in human populations.

Combining conditional and unconditional recruitment incentives could facilitate telephone tracing in surveys of postpartum women

BACKGROUND AND OBJECTIVE

To compare tracing and contact rates using alternative incentives in a computer-assisted telephone interview (CATI) survey among postpartum women.

METHODS

In a randomized trial of 1,061 postpartum women 18-49 years of age selected from four Iowa counties, we compared the effects of: (1) unconditional $5 telephone card incentive enclosed with the introductory letter followed by $25 incentive conditional upon successful telephone tracing, contact, and completion of CATI (Group 1, n = 530) vs. (2) $30 incentive conditional upon subject completion of CATI (Group 2, n = 531).

RESULTS

Overall telephone tracing and contact rates achieved were 67.8% and 66.6%, respectively. Tracing (70.2 vs. 65.4%, P = .09) and contact (68.5 vs. 64.8%, P = .26) rates were consistently higher among subjects assigned the combination of a conditional and an unconditional incentive. The combined incentive type had a greater impact on telephone tracing success rates for subjects on whom we could not initially locate an active telephone number (16.7 vs. 7.3%, P = .07) when compared to subjects for whom we found an active telephone number at the time of mailing the introductory letter (78.9 vs. 75.9%, P = .30).

CONCLUSIONS

Combining conditional and unconditional recruitment incentives can facilitate telephone tracing efforts in surveys conducted among recently postpartum women.

Immunogenetic Determinants of Preeclampsia and Related Pregnancy Disorders

OBJECTIVE

We sought to systematically review the impact of immunogenetic factors, specifically human leukocyte antigen (HLA) allele frequencies, maternal homozygosity, couple sharing, and maternal-fetal sharing, on the risk of preeclampsia and intrauterine growth restriction.

DATA SOURCES

A computerized search of PubMed databases from 1975 to 2003 was performed with the terms "preeclampsia," "eclampsia," "intrauterine growth restriction," and "human leukocyte antigens" and limited to studies of human subjects in English. No restrictions were placed on study design. All bibliographies were cross-referenced to identify additional pertinent studies.

METHODS OF STUDY SELECTION

Titles and abstracts were reviewed carefully. Observational and basic science research studies were selected if their main objective was to assess the relationship of any aspect of HLA genotypes with preeclampsia and related disorders of pregnancy.

TABULATION, INTEGRATION, AND RESULTS

Data were abstracted and tabulated from 22 original research studies. Meta-analytic techniques were not performed owing to variations in disease and exposure definitions as well as research methodologies. Studies that examined maternal, paternal, and fetal HLA allele frequencies, maternal homozygosity, and couple sharing yielded inconsistent results. Although the cumulative evidence points to the HLA-DR locus (particularly DR4) as a correlate of preeclampsia, it remains unclear whether any specific HLA allele, haplotype, or susceptibility gene in linkage disequilibrium with the HLA region is responsible. Although genetic evidence is suggestive of gene-gene interaction between mother and fetus, few studies have evaluated the influence of maternal-fetal HLA sharing.

CONCLUSION

In the early 1990s, HLA genotypes were dismissed as possible etiologic factors for preeclampsia, based on studies that are heterogeneous with respect to study design, outcome, and exposure assessment. Many of these studies did not take into account the interactions between maternal, paternal, and infant genotypes. Thus, adequately powered studies designed specifically to assess the effect of maternal-fetal HLA sharing on risk of preeclampsia are needed.

Association of human leucocyte antigen sharing with recurrent spontaneous abortions

An estimated 15% of clinically recognized pregnancies abort spontaneously. Recurrent spontaneous abortion (RSA) is defined as three or more consecutive miscarriages conceived with the same partner in the absence of uterine, genetic or autoimmune abnormalities. Evidence points to human leucocyte antigens (HLA) as playing a role in the successful development of the foetus. In particular, HLA compatibility is more prevalent in couples experiencing reproductive failure, especially RSA couples, compared to fertile couples. According to the immunological hypothesis, an adequate immune response is necessary for proper implantation of the embryo; conversely, a depressed response of maternal lymphocytes to the stimulation by paternal antigens because of HLA sharing can result in disorders, such as RSA. The genetic hypothesis implicates homozygosity for recessive lethal alleles in linkage disequilibrium with specific HLA haplotypes. The specificity of HLA alleles or haplotypes responsible for or linked to other RSA susceptibility genes remains unclear. In this study, we identified 40 observational studies (32 case-control, five cohort, one cross-sectional, one case series and one basic science) that examined the associations between HLA and RSA, focusing on HLA allele couple and maternal-foetal sharing, and the special role of HLA-G. We sought to identify consistent findings among studies examining similar questions. Evidence remains divided concerning the role of HLA allele couple sharing. Of major concern is the focus of many studies on couple sharing as a proxy measure of maternal-foetal sharing. Therefore, adequately powered studies are needed, which employ standard case definitions and reproducible methodologies to directly assess the role of maternal-foetal HLA sharing on the risk of RSA.

Association of Asthma Diagnosis, Severity, Symptoms, and Treatment With Risk of Preeclampsia

OBJECTIVE

Existing studies relating asthma and preeclampsia provide conflicting results, perhaps due to differences in study populations, varying definitions of asthma, and inadequate control for confounding, particularly asthma medication use. This prospective study examines associations between aspects of asthma (diagnosis, severity, symptoms, and medication use) and risk of preeclampsia.

METHODS

A total of 1,708 pregnant women, of whom 656 had asthma diagnosis and 1,052 had no asthma diagnosis, were included in this analysis. Asthma symptoms, treatment, and severity were classified according to Global Initiative for Asthma guidelines. Hospital records were abstracted, and strict criteria were applied to classify women as preeclamptic based on National Heart, Lung, and Blood Institute guidelines.

RESULTS

There were 568 of 656 women with diagnosed asthma and 353 of 1,052 women without asthma diagnosis who had symptoms or took asthma medication during pregnancy. Separate adjusted logistic regression models were run for different measures of asthma status: 1) asthma diagnosis; 2) overall Global Initiative for Asthma severity; 3) Global Initiative for Asthma symptom and treatment steps; and 4) Global Initiative for Asthma symptom step and medication type. Women at increased risk of preeclampsia were those classified as Global Initiative for Asthma symptom step 3/4 compared with no symptoms (odds ratio 3.36, 95% confidence interval 1.24-9.14) and theophylline users (odds ratio 1.16 for every dose/month increase in use, 95% confidence interval 1.02-1.33). In contrast, neither a history of physician-diagnosed asthma nor Global Initiative for Asthma treatment step was associated with preeclampsia status.

CONCLUSION

Our findings suggest that women with moderate to severe asthma symptoms, regardless of asthma diagnosis or treatment, are at increased risk of preeclampsia compared with women with no symptoms.

Optimizing buccal cell DNA yields in mothers and infants for human leukocyte antigen genotyping

Buccal cells provide a convenient source of DNA for epidemiologic studies. Mouthwash rinses yield a higher quality and quantity of DNA than cytobrushes but are not practical for collection from infants. Although cytobrushes yield sufficient DNA for most genotyping analyses, human leukocyte antigen (HLA) analysis can require 1,000-fold more DNA. In Iowa City, Iowa, in 2002, the authors tested two cytobrush collection methods to optimize total DNA yield and purity for HLA genotyping in mothers and infants: 1) brushing the left and right inner cheeks (standard method) and 2) brushing the upper and lower "gutters", that is, the space between the gums and the inner lips/cheeks along the front and sides of the mouth (test method). Storage and mailing experiments were performed to define conditions for optimizing DNA yield and purity. Mothers' gutter samples yielded significantly higher total amounts of DNA (mean yield = 15.0 micro g/two brushes) than cheek samples (mean yield = 7.6 micro g/two brushes) (paired t test: p < 0.001), while DNA yields from cheek and gutter collections from infants were equivalent. Cytobrushes stored and/or mailed in paper envelopes yielded significantly more and higher-purity DNA than brushes in plastic bags or tubes. Cytobrush sampling of the mouth's gutter areas can enhance DNA yield in mothers but not in young infants. DNA yields can be further optimized by controlling mailing and storage conditions.

Abortion, changed paternity, and risk of preeclampsia in nulliparous women

A prior birth confers a strong protective effect against preeclampsia, whereas a prior abortion confers a weaker protective effect. Parous women who change partners in a subsequent pregnancy appear to lose the protective effect of a prior birth. This study (Calcium for Preeclampsia Prevention Trial, 1992-1995) examines whether nulliparous women with a prior abortion who change partners also lose the protective effect of the prior pregnancy. A cohort analysis was conducted among participants in this large clinical trial of calcium supplementation to prevent preeclampsia. Subjects were nulliparous, had one prior pregnancy or less, delivered after 20 weeks' gestation, and were interviewed at 5-21 weeks about prior pregnancies and paternity. Women without a history of abortion served as the reference group in logistic regression analyses. Women with a history of abortion who conceived again with the same partner had nearly half the risk of preeclampsia (adjusted odds ratio = 0.54, 95 percent confidence interval: 0.31, 0.97). In contrast, women with an abortion history who conceived with a new partner had the same risk of preeclampsia as women without a history of abortion (adjusted odds ratio = 1.03, 95 percent confidence interval: 0.72, 1.47). Thus, the protective effect of a prior abortion operated only among women who conceived again with the same partner. An immune-based etiologic mechanism is proposed, whereby prolonged exposure to fetal antigens from a previous pregnancy protects against preeclampsia in a subsequent pregnancy with the same father.

Maternal caffeine intake and intrauterine growth retardation

This study estimates the effect of maternal caffeine consumption throughout pregnancy on fetal growth. We studied 2,714 women who delivered a liveborn infant between 1988 and 1991. Detailed information regarding coffee, tea, and soda drinking during the first and third trimesters of pregnancy was obtained. Average caffeine intake during month 1 of pregnancy was higher than for month 7 (72.4 vs 54.0 mg per day). Consumption of >300 mg caffeine per day during month 1 (adjusted odds ratio = 0.91; 95% confidence interval = 0.44--1.90) and during month 7 (adjusted odds ratio = 1.00; 95% confidence interval = 0.37--2.70) was not associated with intrauterine growth retardation. There was little evidence for any effect modification due to cigarette smoking on the caffeine associations. This study provides evidence that antenatal caffeine consumption has no adverse effect on fetal growth.

Racial disparity in pregnancy-related mortality associated with livebirth: can established risk factors explain it?

The authors conducted a nested case-control study to determine whether the fourfold increased risk of pregnancy-related mortality for US Black women compared with White women can be explained by racial differences in sociodemographic and reproductive factors. Cases were derived from a national surveillance database of pregnancy-related deaths and were restricted to White women (n = 840) and Black women (n = 448) whose pregnancies resulted in a livebirth and who died of a pregnancy-related cause between 1979 and 1986. Controls were derived from national natality data and were randomly selected White women and Black women who delivered live infants and did not die from a pregnancy-related cause (n = 5,437). Simultaneous adjustment for risk factors by using logistic regression did not explain the racial gap in pregnancy-related mortality. The largest racial disparity occurred among women with the lowest risk of pregnancy-related death: those of low to moderate parity who delivered normal-birth-weight babies (adjusted odds ratio = 3.53, 95% confidence interval: 2.9, 4.4). In contrast, no racial disparity was found among women with the highest risk of pregnancy-related death: high-parity women who delivered low-birth-weight babies. These findings indicate that reproductive health care professionals need to develop strategies to reduce pregnancy-related deaths among both high- and low-risk Black women.

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.

Maternal anthropometric factors and risk of primary cesarean delivery

OBJECTIVES

This study examined absolute and proportional gestational weight gain and prepregnancy body mass index as predictors of primary cesarean delivery.

METHODS

Data were derived from a prospective study of pregnancy outcome risk factors in 2301 women in greater New Haven, Conn, who had singleton deliveries by primary cesarean (n = 312) or vaginal delivery (n = 1989) and for whom height, prepregnancy weight, and weight gain were available. Women were divided into 4 body mass index groups (underweight, low average, high average, and obese) and further subdivided into 8 groups according to median proportional or absolute weight gain.

RESULTS

Risk of cesarean delivery increased with increasing body mass index and gestational weight gain greater than the median for one's body mass index. Proportional weight gain was more predictive of cesarean delivery than absolute weight gain. Underweight women gaining more than 27.8% of their prepregnancy weight had a 2-fold adjusted relative risk of cesarean delivery.

CONCLUSIONS

Proportional weight gain is an important predictor of cesarean delivery for underweight women; high body mass index is also predictive of increased risk.