Ranked severe maternal morbidity index for population-level surveillance at delivery hospitalization based on hospital discharge data.

BACKGROUND: Severe maternal morbidity (SMM) is broadly defined as an unexpected and potentially life-threatening event associated with labor and delivery. The Centers for Disease Control and Prevention (CDC) produced 21 different indicators based on International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) hospital diagnostic and procedure codes to identify cases of SMM. OBJECTIVES: To examine existing SMM indicators and determine which indicators identified the most in-hospital mortality at delivery hospitalization. METHODS: Data from the 1993-2015 and 2017-2019 Healthcare Cost and Utilization Project's National Inpatient Sample were used to report SMM indicator-specific prevalences, in-hospital mortality rates, and population attributable fractions (PAF) of mortality. We hierarchically ranked indicators by their overall PAF of in-hospital mortality. Predictive modeling determined if SMM prevalence remained comparable after transition to ICD-10-CM coding. RESULTS: The study population consisted of 18,198,934 hospitalizations representing 87,864,173 US delivery hospitalizations. The 15 top ranked indicators identified 80% of in-hospital mortality; the proportion identified by the remaining indicators was negligible (2%). The top 15 indicators were: restoration of cardiac rhythm; cardiac arrest; mechanical ventilation; tracheostomy; amniotic fluid embolism; aneurysm; acute respiratory distress syndrome; acute myocardial infarction; shock; thromboembolism, pulmonary embolism; cerebrovascular disorders; sepsis; both DIC and blood transfusion; acute renal failure; and hysterectomy. The overall prevalence of the top 15 ranked SMM indicators (~22,000 SMM cases per year) was comparable after transition to ICD-10-CM coding. CONCLUSIONS: We determined the 15 indicators that identified the most in-hospital mortality at delivery hospitalization in the US. Continued testing of SMM indicators can improve measurement and surveillance of the most severe maternal complications at the population level.

Clinical Practice Changes in Monitoring Hypertension Early in the COVID-19 Pandemic.

BACKGROUND: Clinical practices can use telemedicine and other strategies (e.g., self-measured blood pressure [SMBP]) for remote monitoring of hypertension to promote control while decreasing risk of exposure to SARS-CoV-2, the virus that causes COVID-19. METHODS: The DocStyles survey collected data from primary care providers (PCPs), obstetricians-gynecologists (OB/GYNs), and nurse practitioners/physician assistants (NP/PAs) in fall 2020 (n = 1,502). We investigated clinical practice changes for monitoring hypertension that were implemented early in the COVID-19 pandemic and examined differences by clinician and practice characteristics (P < 0.05). RESULTS: Overall, 369 (24.6%) of clinicians reported their clinical practices made no changes in monitoring hypertension early in the pandemic, 884 (58.9%) advised patients to monitor blood pressure at home or a pharmacy, 699 (46.5%) implemented or increased use of telemedicine for blood pressure monitoring visits, and 545 (36.3%) reduced the frequency of office visits for blood pressure monitoring. Compared with NP/PAs, PCPs were more likely to advise SMBP monitoring (adjusted prevalence ratios [aPR] 1.28, 95% confidence intervals [CI] 1.11-1.47), implement or increase use of telemedicine (aPR 1.23, 95% CI 1.04-1.46), and reduce the frequency of office visits (aPR 1.37, 95% CI 1.11-1.70) for blood pressure monitoring, and less likely to report making no practice changes (aPR 0.63, 95% CI 0.51-0.77). CONCLUSIONS: We noted variation in clinical practice changes by clinician type and practice characteristics. Clinical practices may need additional support and resources to fully maximize telemedicine and other strategies for remote monitoring of hypertension during pandemics and other emergencies that can disrupt routine health care.

Hypertensive Disorders in Pregnancy and Mortality at Delivery Hospitalization - United States, 2017-2019.

Hypertensive disorders in pregnancy (HDPs), defined as prepregnancy (chronic) or pregnancy-associated hypertension, are common pregnancy complications in the United States.* HDPs are strongly associated with severe maternal complications, such as heart attack and stroke (1), and are a leading cause of pregnancy-related death in the United States.† CDC analyzed nationally representative data from the National Inpatient Sample to calculate the annual prevalence of HDP among delivery hospitalizations and by maternal characteristics, and the percentage of in-hospital deaths with an HDP diagnosis code documented. During 2017-2019, the prevalence of HDP among delivery hospitalizations increased from 13.3% to 15.9%. The prevalence of pregnancy-associated hypertension increased from 10.8% in 2017 to 13.0% in 2019, while the prevalence of chronic hypertension increased from 2.0% to 2.3%. Prevalence of HDP was highest among delivery hospitalizations of non-Hispanic Black or African American (Black) women, non-Hispanic American Indian and Alaska Native (AI/AN) women, and women aged ≥35 years, residing in zip codes in the lowest median household income quartile, or delivering in hospitals in the South or the Midwest Census regions. Among deaths that occurred during delivery hospitalization, 31.6% had any HDP documented. Clinical guidance for reducing complications from HDP focuses on prompt identification and preventing progression to severe maternal complications through timely treatment (1). Recommendations for identifying and monitoring pregnant persons with hypertension include measuring blood pressure throughout pregnancy,§ including self-monitoring. Severe complications and mortality from HDP are preventable with equitable implementation of strategies to identify and monitor persons with HDP (1) and quality improvement initiatives to improve prompt treatment and increase awareness of urgent maternal warning signs (2).

Variations in Low-Risk Cesarean Delivery Rates in the United States Using the Society for Maternal-Fetal Medicine Definition.

OBJECTIVE: To assess variations in low-risk cesarean delivery rates in the United States using the Society for Maternal-Fetal Medicine (SMFM) definition of low-risk for cesarean delivery and to identify factors associated with low-risk cesarean deliveries. METHODS: From hospital discharge data in the 2018 National Inpatient Sample and State Inpatient Databases, we identified deliveries that were low-risk for cesarean delivery using the SMFM definition based on the International Classification of Diseases, Tenth Revision, Clinical Modification codes. We estimated national low-risk cesarean delivery rates overall and by patient characteristics, clinically relevant conditions not included in the SMFM definition, and hospital characteristics based on the nationally representative sample of hospital discharges in the National Inpatient Sample. Multivariate logistic regressions were estimated for the national sample to identify factors associated with low-risk cesarean delivery. We reported low-risk cesarean delivery rates for 27 states and the District of Columbia based on the annual state data that represented the universe of hospital discharges from participating states in the State Inpatient Databases. RESULTS: Of an estimated 3,634,724 deliveries in the 2018 National Inpatient Sample, 2,484,874 low-risk deliveries met inclusion criteria. The national low-risk cesarean delivery rate in 2018 was 14.6% (95% CI 14.4-14.8%). The rates varied widely by state (range 8.9-18.6%). Nationally, maternal age older than 40 years, non-Hispanic Black or Asian race, private insurance as primary payer, admission on weekday, obesity, diabetes, or hypertension, large metropolitan residence, and hospitals of the South census region were associated with low-risk cesarean delivery. CONCLUSION: Approximately one in seven low-risk deliveries was by cesarean in 2018 in the United States using the SMFM definition and the low-risk cesarean delivery rates varied widely by state.

Assessment of Incidence and Factors Associated With Severe Maternal Morbidity After Delivery Discharge Among Women in the US.

Importance: Previous efforts to examine severe maternal morbidity (SMM) in the US have focused on delivery hospitalizations. Little is known about de novo SMM that occurs after delivery discharge. Objective: To investigate the incidence, timing, factors, and maternal characteristics associated with de novo SMM after delivery discharge among women in the US. Design, Setting, and Participants: In this retrospective cohort study, data from the IBM MarketScan Multi-State Medicaid database and the IBM MarketScan Commercial Claims and Encounters database were used to construct a sample of women aged 15 to 44 years who delivered between January 1, 2010, and September 30, 2014. Severe maternal morbidity was reported by the timing of diagnosis, and the associated maternal characteristics were examined. Women in the Medicaid and commercial insurance sample were classified into 3 distinct outcome groups: (1) those without any SMM during the delivery hospitalization and the postdelivery period (reference group), (2) those who exhibited at least 1 factor associated with SMM during the delivery hospitalization, and (3) those who exhibited any factor associated with de novo SMM after delivery discharge (defined as SMM that was first diagnosed in the inpatient setting during the 6 weeks [or 42 days] after discharge from the delivery hospitalization, conditional on no factor associated with SMM being identified during delivery). Data were analyzed from February to July 2020. Exposures: Timing of SMM diagnosis. Main Outcomes and Measures: Women with SMM were identified using diagnosis and procedure codes from the International Classification of Diseases, Ninth Revision, Clinical Modification for the 21 factors associated with SMM that were developed by the Centers for Disease Control and Prevention. Results: A total of 2 667 325 women in the US with delivery hospitalizations between 2010 and 2014 were identified; of those, 809 377 women (30.3%) had Medicaid insurance (30.3%; mean [SD] age, 25.6 [5.5] years; 51.1% White), and 1 857 948 women (69.7%; mean [SD] age, 30.6 [5.4] years; 36.4% from the southern region of the US) had commercial insurance. Among those with Medicaid insurance, 17 584 women (2.2%) experienced SMM during the delivery hospitalization, and 3265 women (0.4%) experienced de novo SMM after delivery discharge. Among those with commercial insurance, 32 079 women (1.7%) experienced SMM during the delivery hospitalization, and 5275 women (0.3%) experienced de novo SMM after hospital discharge. A total of 5275 SMM cases (14.1%) and 3265 SMM cases (15.7%) among women with commercial and Medicaid insurance, respectively, developed de novo within 6 weeks after hospital discharge; of those, 3993 cases (75.7%) in the commercial insurance cohort and 2399 cases (73.5%) in the Medicaid cohort were identified in the first 2 weeks after discharge. The most common factors associated with SMM varied based on the timing of diagnosis. In the Medicaid population, non-Hispanic Black women (adjusted odds ratio [aOR], 1.53; 95% CI, 1.48-1.58), Hispanic women (aOR, 1.46; 95% CI, 1.37-1.57), and women of other races or ethnicities (aOR, 1.40; 95% CI, 1.33-1.47) had higher rates of SMM during delivery hospitalization than non-Hispanic White women; however, only the disparity between Black and White women (aOR, 1.69; 95% CI, 1.57-1.81) persisted into the postdischarge period. Conclusions and Relevance: In this study, 15.7% of SMM cases in the Medicaid cohort and 14.1% of SMM cases in the commercial insurance cohort first occurred after the delivery hospitalization, with notable disparities in factors and maternal characteristics associated with the development of SMM. These findings suggest a need to expand the focus of SMM assessment to the postdelivery discharge period.

Frequency of cannabis use during pregnancy and adverse infant outcomes, by cigarette smoking status - 8 PRAMS states, 2017.

BACKGROUND: Research on prenatal cannabis use and adverse infant outcomes is inconsistent, and findings vary by frequency of use or cigarette use. We assess (1) the prevalence of high frequency (≥once/week), low frequency (

Report of the Office of Population Affairs' expert work group meeting on short birth spacing and adverse pregnancy outcomes: Methodological quality of existing studies and future directions for research.

BACKGROUND: The World Health Organization (WHO) recommends that women wait at least 24 months after a livebirth before attempting a subsequent pregnancy to reduce the risk of adverse maternal, perinatal, and infant health outcomes. However, the applicability of the WHO recommendations for women in the United States is unclear, as breast feeding, nutrition, maternal age at first birth, and total fertility rate differs substantially between the United States and the low- and middle-resource countries upon which most of the evidence is based. METHODS: To inform guideline development for birth spacing specific to women in the United States, the Office of Population Affairs (OPA) convened an expert work group meeting in Washington, DC, on 14-15 September 2017 among reproductive, perinatal, paediatric, social, and public health epidemiologists; obstetrician-gynaecologists; biostatisticians; and experts in evidence synthesis related to women's health. RESULTS: Presentations and discussion topics included the methodological quality of existing studies, evaluation of the evidence for causal effects of short interpregnancy intervals on adverse perinatal and maternal health outcomes, good practices for future research, and identification of research gaps and priorities for future work. CONCLUSIONS: This report provides an overview of the presentations, discussions, and conclusions from the expert work group meeting.

Good practices for the design, analysis, and interpretation of observational studies on birth spacing and perinatal health outcomes.

BACKGROUND: Meta-analyses of observational studies have shown that women with a shorter interpregnancy interval (the time from delivery to start of a subsequent pregnancy) are more likely to experience adverse pregnancy outcomes, such as preterm delivery or small for gestational age birth, than women who space their births further apart. However, the studies used to inform these estimates have methodological shortcomings. METHODS: In this commentary, we summarise the discussions of an expert workgroup describing good practices for the design, analysis, and interpretation of observational studies of interpregnancy interval and adverse perinatal health outcomes. RESULTS: We argue that inferences drawn from research in this field will be improved by careful attention to elements such as: (a) refining the research question to clarify whether the goal is to estimate a causal effect vs describe patterns of association; (b) using directed acyclic graphs to represent potential causal networks and guide the analytic plan of studies seeking to estimate causal effects; (c) assessing how miscarriages and pregnancy terminations may have influenced interpregnancy interval classifications; (d) specifying how key factors such as previous pregnancy loss, pregnancy intention, and maternal socio-economic position will be considered; and (e) examining if the association between interpregnancy interval and perinatal outcome differs by factors such as maternal age. CONCLUSION: This commentary outlines the discussions of this recent expert workgroup, and describes several suggested principles for study design and analysis that could mitigate many potential sources of bias.

Effects of Maternal Age and Age-Specific Preterm Birth Rates on Overall Preterm Birth Rates - United States, 2007 and 2014.

Reductions in births to teens and preterm birth rates are two recent public health successes in the United States (1,2). From 2007 to 2014, the birth rate for females aged 15-19 years declined 42%, from 41.5 to 24.2 per 1,000 females. The preterm birth rate decreased 8.4%, from 10.41% to 9.54% of live births (1). Rates of preterm births vary by maternal age, being higher among the youngest and oldest mothers. It is unknown how changes in the maternal age distribution in the United States have affected preterm birth rates. CDC used birth data to assess the relative contributions of changes in the maternal age distribution and in age-specific preterm birth rates to the overall decrease in preterm birth rates. The preterm birth rate declined in all age groups. The effects of age distribution changes on the preterm birth rate decrease were different in younger and older mothers. The decrease in the proportion of births to mothers aged ≤19 and 20-24 years and reductions in age-specific preterm rates in all age groups contributed to the overall decline in the preterm birth rate. The increase in births to mothers aged ≥30 years had no effect on the overall preterm birth rate decrease. The decline in preterm births from 2007 to 2014 is related, in part, to teen pregnancy prevention and the changing maternal age distribution. Effective public health strategies for further reducing preterm birth rates need to be tailored to different age groups.

Maternal Serum 25-Hydroxyvitamin D Concentrations during Pregnancy and Infant Birthweight for Gestational Age: a Three-Cohort Study.

BACKGROUND: In response to inconsistent findings, we investigated associations between maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations and infant birthweight for gestational age (BW/GA), including potential effect modification by maternal race/ethnicity and infant sex. METHODS: Data from 2558 pregnant women were combined in a nested case-control study (preterm and term) sampled from three cohorts: the Omega study, the Pregnancy, Infection and Nutrition study, and the Pregnancy Outcomes and Community Health study. Maternal 25(OH)D concentrations were sampled at 4 to 29 weeks gestation (80% 14-26 weeks). BW/GA was modelled as sex and gestational age-specific birthweight z-scores. General linear regression models (adjusting for age, education, parity, pre-pregnancy body mass index, season at blood draw, and smoking) assessed 25(OH)D concentrations in relation to BW/GA. RESULTS: Among non-Hispanic Black women, the positive association between 25(OH)D concentrations and BW/GA was of similar magnitude in pregnancies with female or male infants [beta (ß) = 0.015, standard error (SE) = 0.007, P = 0.025; ß = 0.018, SE = 0.006, P = 0.003, respectively]. Among non-Hispanic White women, 25(OH)D-BW/GA association was observed only with male infants, and the effect size was lower (ß = 0.008, SE = 0.003, P = 0.02). CONCLUSIONS: Maternal serum concentrations of 25(OH)D in early and mid-pregnancy were positively associated with BW/GA among non-Hispanic Black male and female infants and non-Hispanic White male infants. Effect modification by race/ethnicity may be due, in part, to overall lower concentrations of 25(OH)D in non-Hispanic Blacks. Reasons for effect modification by infant sex remain unclear.

Seasonal variation of 25-hydroxyvitamin D among non-Hispanic black and white pregnant women from three US pregnancy cohorts.

BACKGROUND: Vitamin D deficiency during pregnancy has been associated with increased risk of complications and adverse perinatal outcomes. We evaluated seasonal variation of 25-hydroxyvitamin D [25(OH)D] among pregnant women, focusing on patterns and determinants of variation. METHODS: Data came from three cohort studies in the US that included 2583 non-Hispanic Black and White women having prenatal 25(OH)D concentrations determined. Fourier time series and generalised linear models were used to estimate the magnitude of 25(OH)D seasonality. We modelled seasonal variability using a stationary cosinor model to estimate the phase shift, peak-trough difference, and annual mean of 25(OH)D. RESULTS: We observed a peak for 25(OH)D in summer, a nadir in winter, and a phase of 8 months, which resulted from fluctuations in 25(OH)D3 rather than 25(OH)D2. After adjustment for covariates, the annual mean concentrations and estimated peak-trough difference of 25(OH)D among Black women were 19.8 ng/mL [95% confidence interval (CI) 18.9, 20.5] and 5.8 ng/mL [95% CI 4.7, 6.7], and for non-Hispanic White women were 33.0 ng/mL [95% CI 32.6, 33.4] and 7.4 ng/mL [95% CI 6.0, 8.9]. CONCLUSIONS: Non-Hispanic Black women had lower average 25(OH)D concentrations throughout the year and smaller seasonal variation levels than non-Hispanic White women. This study's confirmation of 25(OH)D seasonality over a calendar year has the potential to enhance public health interventions targeted to improve maternal and perinatal outcomes.

Recent changes in the trends of teen birth rates, 1981-2006.

PURPOSE: To explore trends in teen birth rates by selected demographics. METHODS: We used birth certificate data and joinpoint regression to examine trends in teen birth rates by age (10-14, 15-17, and 18-19 years) and race during 1981-2006 and by age and Hispanic origin during 1990-2006. Joinpoint analysis describes changing trends over successive segments of time and uses annual percentage change (APC) to express the amount of increase or decrease within each segment. RESULTS: For teens younger than 18 years, the decline in birth rates began in 1994 and ended in 2003 (APC: -8.03% per year for ages 10-14 years; APC: -5.63% per year for ages 15-17 years). The downward trend for 18- and 19-year-old teens began earlier (1991) and ended 1 year later (2004) (APC: -2.37% per year). For each study population, the trend was approximately level during the most recent time segment, except for continuing declines for 18- and 19-year-old white and Asian/Pacific Islander teens. The only increasing trend in the most recent time segment was for 18- and 19-year-old Hispanic teens. During these declines, the age distribution of teens who gave birth shifted to slightly older ages, and the percentage whose current birth was at least their second birth decreased. CONCLUSIONS: Teen birth rates were generally level during 2003/2004-2006 after the long-term declines. Rates increased among older Hispanic teens. These results indicate a need for renewed attention to effective teen pregnancy prevention programs in specific populations.

Changing trends in low birth weight rates among non-Hispanic black infants in the United States, 1991-2004.

We examined trends in low birth weight (LBW, <2,500 g) rates among US singleton non-Hispanic black infants between 1991 and 2004. We conducted Joinpoint regression analyses, using birth certificate data, to describe trends in LBW, moderately LBW (MLBW, 1,500-2,499 g), and very LBW (VLBW, <1,500 g) rates. We then conducted cross-sectional and binomial regression analyses to relate these trends to changes in maternal or obstetric factors. Non-Hispanic black LBW rates declined -7.35% between 1991 and 2001 and then increased +4.23% through 2004. The LBW trends were not uniform across birth weight subcategories. Among MLBW births, the 1991-2001 decease was -10.20%; the 2001-2004 increase was +5.61%. VLBW did not follow this pattern, increasing +3.84% between 1991 and 1999 and then remaining relatively stable through 2004. In adjusted models, the 1991-2001 MLBW rate decrease was associated with changes in first-trimester prenatal care, cigarette smoking, education levels, maternal foreign-born status, and pregnancy weight gain. The 2001-2004 MLBW rate increase was independent of changes in observed maternal demographic characteristics, prenatal care, and obstetric variables. Between 1991 and 2001, progress occurred in reducing MLBW rates among non-Hispanic black infants. This progress was not maintained between 2001 and 2004 nor did it occur for VLBW infants between 1991 and 2004. Observed population changes in maternal socio-demographic and health-related factors were associated with the 1991-2001 decrease, suggesting multiple risk factors need to be simultaneously addressed to reduce non-Hispanic black LBW rates.

The Healthy African American Families (HAAF) project: from community-based participatory research to community-partnered participatory research.

During the past two decades, there has been an increased use of community-based participatory research in public health activities, especially as part of efforts to understand health disparities affecting communities of color. This article describes the history and lessons learned of a long-standing community participatory project, Healthy African American Families (HAAF), in Los Angeles, California. HAAF evolved from a partnership formed by a community advisory board, university, and federal health agency to an independent, incorporated community organization that facilitates and brokers research and health promotion activities within its community. HAAF created mechanisms for community education and networks of community relationships and reciprocity through which mutual support, research, and interventions are integrated. These sustained, institutionalized relationships unite resources and both community and scientific expertise in a community-partnered participatory research model to address multiple health problems in the community, including preterm birth, HIV, asthma, depression, and diabetes. The HAAF participatory process builds on existing community resiliency and resources and on centuries of self-help, problem-solving, cooperative action, and community activism within the African American community. HAAF demonstrates how community-partnered participatory research can be a mechanism for directing power, collective action, system change, and social justice in the process of addressing health disparities at the community level.

One Hundred Intentional Acts of Kindness toward a Pregnant Woman: building reproductive social capital in Los Angeles.

This article describes the development of an innovative community-based program, One Hundred Intentional Acts of Kindness toward a Pregnant Woman (100 Acts), which seeks to increase reproductive social capital for pregnant women in south and central Los Angeles communities. Reproductive social capital includes features such as networks, norms, and social trust that facilitate optimal reproductive health within a community. 100 Acts was designed and developed by the Healthy African American Families project, using community participatory methods, to increase local community and social network support for pregnant women. Dialog groups with pregnant women identified specific actions that families, friends, and strangers might do to support pregnancies. Participants primarily wanted emotional and instrumental support from family and friends. From strangers, they wanted respect for personal space and common courtesy. Based on these results, the 100 Acts was created for use in the Los Angeles community. 100 Acts encourages and engages active participation from community members in promoting healthy pregnancies. By seeking to increase community-level reproductive social capital, 100 Acts shifts the provision of social support during pregnancy from a high-risk approach to a population approach. 100 Acts also establishes new social norms about how pregnant women are valued, treated and respected.

Current research in preterm birth.

Preterm birth is one of the leading causes of infant mortality and the leading cause of infant morbidity in the United States. It accounts for >70% of neonatal deaths and almost half of long-term neurological disabilities. The Centers for Disease Control and Prevention (CDC) is collaborating with state health departments, universities, communities, and healthcare providers to understand why preterm births occur and how to address preterm birth risk factors. These collaborations include identification of genetic and other biological markers for the early detection of women at high risk of preterm birth; improving understanding of the relationships among psychosocial stress, immune and inflammatory responses, and preterm risk; and designing community strategies to improve the health of pregnant women. By conducting public health research activities that explore the genetic, biological, clinical, behavioral, social, and community determinants of preterm birth, CDC will continue to elucidate the complex interactions of these factors and how they influence preterm birth.

Perinatal outcomes of twin births conceived using assisted reproduction technology: a population-based study.

BACKGROUND: Approximately 18% of multiple births in the USA result from assisted reproduction technology (ART). Although many studies comparing ART and naturally conceived twins report no difference in risks for perinatal outcomes, others report slight to moderate positive or protective associations. METHODS: We selected twin deliveries with and without indication of ART from Massachusetts live birth-infant death records from 1997 to 2000 linked to the US ART surveillance system. The sample was restricted to deliveries by mothers with increased socioeconomic status, private health insurance and intermediate/plus prenatal care use. Our final sample included 1446 and 2729 ART and non-ART twin deliveries, respectively. Odds ratios (OR) for associations between ART and perinatal outcomes were adjusted for maternal demographic factors, smoking, prenatal care and hospital care level. RESULTS: ART twin deliveries were less likely than non-ART to be very preterm (adjusted OR 0.75; 95% confidence interval 0.58-0.97) or include a very low birthweight (<1500 g) infant (0.75; 0.58-0.95) or infant death (0.55; 0.35-0.88). In stratified analyses, these findings were observed among primiparous deliveries, but there were no risk differences among multiparous ART and non-ART twin deliveries. CONCLUSIONS: ART treatment was not a risk factor for adverse perinatal outcome, and risks for several outcomes were somewhat lower among ART twin deliveries. Nonetheless, ART is strongly associated with twinning and twins remain a high-risk group, relative to singletons. Promoting singleton gestation in assisted conception is an important strategy for reducing adverse outcomes.

A population-based study of maternal and perinatal outcomes associated with assisted reproductive technology in Massachusetts.

OBJECTIVE: To assess associations between assisted reproductive technology (ART) and adverse maternal and infant outcomes, with an emphasis on singletons. METHODS: We linked data from the US ART surveillance system with Massachusetts live birth-infant death records data for resident births in 1997-1998 and compared births conceived with ART (N = 3316) with births not conceived with ART or infertility medications (N = 157,066) on: maternal chronic conditions, pregnancy complications, labor and delivery complications, and perinatal and infant outcomes. RESULTS: Overall, ART was strongly associated with numerous adverse outcomes. The magnitude was reduced for several outcomes when analyses were limited to singletons. After further exclusion of maternal subsets with rare ART births (maternal age <20; education