Odds Of Preterm Delivery Research Articles

Exploring the relationship of second-trimester corticotropin releasing hormone, chronic stress and preterm delivery

Objective. We examined the impact of chronic stress on the relationship between second-trimester serum corticotropin releasing hormone (CRH) concentrations and preterm delivery (PTD) in working women.Methods. Birth records from mothers of 364 PTD and 730 controls in Southern California were linked to stored mid-pregnancy maternal serum analysed for CRH. Association of CRH with stressors reported in post-partum interviews was examined in cases and controls separately. Stratified multivariable logistic regression analyses examined moderating influence of seven chronic stressors on CRH in predicting PTD.Results. Mean log CRH was lower among women with chronic stressors. Chronic stressors were not related to an increased risk of PTD, but did strengthen the association of CRH with PTD. Adjusted for confounders, the odds of PTD were 1.5-times higher per unit increase in log CRH in the overall study population, but were two-to-three times higher in subjects who reported unfulfilling jobs, little sleep or strong anger in the second trimester.Conclusion. The relation of CRH with PTD is moderated by exposure to chronic stressors during pregnancy.

Presence of the Sickle Cell Trait and Preterm Delivery in African-American Women

To estimate the association between presence of the sickle cell trait and preterm delivery among African-American women. A retrospective cohort study was conducted to study all deliveries by African-American women at one institution between 1976 and 2001. The primary predictor of interest was the presence of the sickle cell trait, and the primary outcome was preterm delivery. Post hoc analyses were conducted to explore the relationship between presence of sickle cell trait and multiple gestations, an apparent modifier of the relationship between sickle cell trait and preterm delivery. Of the 5,028 African-American women eligible for inclusion, 6.5% carried the sickle cell trait. In adjusted analyses, the presence of sickle cell trait was associated with a lower risk of preterm delivery at less than 32 weeks (adjusted odds ratio 0.15, 95% confidence interval 0.05-0.49), and was found to be associated with an increased odds of multiple gestations (adjusted odds ratio 1.94, 95% confidence interval 1.22-2.09). A significant interaction exists between the presence of multiple gestation and sickle cell trait and the odds of preterm delivery, such that the protective effect of sickle cell trait on preterm delivery risk is greater among those with multiple gestations than those with singletons. Among African-American women, the presence of the sickle cell trait was associated with lower odds of early preterm delivery despite adjustment for potential confounders. An increased odds of multiple gestations was also noted among these women, possibly suggesting a persistence of selection for the hemoglobin S trait in nonmalarial settings. II.

The effect of antepartum periodontal therapy on preterm birth rate according to cervical length: A randomized pilot study

RATE ACCORDING TO CERVICAL LENGTH: A RANDOMIZED PILOT STUDY SARAH SMITH, ROBERT STRAUSS, STEVEN OFFENBACHER, KEVIN MOSS, KIM BOGGESS, SALLY TIMLIN, JAMES BECK, University ofNorthCarolina atChapel Hill, Obstetrics/Gynecology, Chapel Hill, North Carolina, University ofNorth Carolina at Chapel Hill, Center for Oral and Systemic Diseases, Chapel Hill, North Carolina, University of North Carolina at Chapel Hill, Dental Ecology, Chapel Hill, North Carolina, WakeMed, Obstetrics/Gynecology, Raleigh, North Carolina OBJECTIVE: To determine if cervical length affects the impact of antepartum periodontal therapy on preterm birth rate. STUDY DESIGN: This was a randomized controlled pilot study to determine the effect of antepartum periodontal therapy on preterm birth risk among women at high risk for preterm birth (prior spontaneous PTB). Women with periodontal disease identified at dental screening visit !16 weeks were randomized to antepartum periodontal therapy. The antepartum intervention group received periodontal scaling and root planning at 16-20 weeks gestation followed by use of a Sonicare-Plus power toothbrush with oral health instructions the remainder of the pregnancy. The control group received a manual toothbrush without oral health instructions. At 22 weeks’ gestation, participants underwent a transvaginal ultrasound for cervical length measurement. The primary outcome was preterm delivery !37 weeks. RESULTS: Baseline characteristics including cervical length of the 31 women in the periodontal intervention group and the 32 women in the control group were similar, except for baseline periodontal pockets which were unbalanced after randomization. Among women with a cervical length !30 mm, preterm delivery was similar between the control and intervention groups (50% versus 38%, P=0.66). Compared to women with a cervical length 30 mm, preterm delivery was also similar between the control and intervention groups (41% versus 22%, P=0.17). However, after adjusting for the baseline imbalance in periodontal disease among women with a cervical length 30 mm, periodontal therapy significantly decreased the odds of preterm delivery (OR=0.12; 95% CI 0.02-0.78). For women with cervical length !30 mm the intervention did not reach significance (OR= 0.61; 95% CI 0.09-4.13). CONCLUSION: In women with periodontal disease at the beginning of pregnancy, periodontal treatment may be more effective in preventing preterm delivery among women with normal cervical length compared to women with shortened cervix.

Disparities in exposure to air pollution during pregnancy.

Previous research shows poorer birth outcomes for racial and ethnic minorities and for persons with low socioeconomic status (SES). We evaluated whether mothers in groups at higher risk for poor birth outcomes live in areas of higher air pollution and whether higher exposure to air pollution contributes to poor birth outcomes. An index representing long-term exposure to criteria air pollutants was matched with birth certificate data at the county level for the United States in 1998-1999. We used linear regression to estimate associations between the air pollution index and maternal race and educational attainment, a marker for SES of the mother, controlling for age, parity, marital status, and region of the country. Then we used logistic regression models both to estimate likelihood of living in counties with the highest levels of air pollution for different racial groups and by educational attainment, adjusting for other maternal risk factors, and to estimate the effect of living in counties with higher levels of air pollution on preterm delivery and births small for gestational age (SGA). Hispanic, African-American, and Asian/Pacific Islander mothers experienced higher mean levels of air pollution and were more than twice as likely to live in the most polluted counties compared with white mothers after controlling for maternal risk factors, region, and educational status [Hispanic mothers: adjusted odds ratio (AOR) = 4.66; 95% confidence interval (95% CI), 1.92-11.32; African-American mothers: AOR = 2.58; 95% CI, 1.00-6.62; Asian/Pacific Islander mothers: AOR = 2.82; 95% CI, 1.07-7.39]. Educational attainment was not associated with living in counties with highest levels of the air pollution index (AOR = 0.95; 95% CI, 0.40-2.26) after adjusting for maternal risk factors, region of the country, and race/ethnicity. There was a small increase in the odds of preterm delivery (AOR = 1.05; 95% CI, 0.99-1.12) but not SGA (AOR = 0.96; 95% CI, 0.86-1.07) in a county with high air pollution. Additional risk of residing in areas with poor air quality may exacerbate health problems of infants and children already at increased risk for poor health.

Maternal serum dioxin levels and birth outcomes in women of Seveso, Italy.

2,3,7,8-Tetrachlorodibenzo-(italic)para(/italic)-dioxin (TCDD), a ubiquitous environmental contaminant, is associated with increased fetal loss and reduced birth weight in animal studies. In 1976, an explosion at a trichlorophenol plant near Seveso, Italy, resulted in the highest TCDD exposure known in human residential populations. In 1996, we initiated the Seveso Women's Health Study, a retrospective cohort study of women who resided in the most contaminated areas, zones A and B. We examined the relation of pregnancy outcome in 510 women (888 total pregnancies) to maternal TCDD levels measured in serum collected shortly after the explosion. Ninety-seven pregnancies (10.9%) ended as spontaneous abortions (SABs). There was no association of log(subscript)10(/subscript) TCDD with SAB [adjusted odds ratio (OR) = 0.8; 95% confidence interval (CI), 0.6-1.2], with birth weight (adjusted beta = -4 g; 95% CI, -68 to 60), or with births that were small for gestational age (SGA) (adjusted OR = 1.2; 95% CI, 0.8-1.8). However, associations with birth weight (adjusted beta = -92 g; 95% CI, -204 to 19) and with SGA (adjusted OR = 1.4; 95% CI, 0.6-2.9) were stronger for pregnancies within the first 8 years after exposure. TCDD was associated with a 1.0-1.3 day nonsignificant adjusted decrease in gestational age and a 20-50% nonsignificant increase in the odds of preterm delivery. It remains possible that the effects of TCDD on birth outcomes are yet to be observed, because the most heavily exposed women in Seveso were the youngest and the least likely to have yet had a pregnancy.

After Abortion, Danish Women's Odds of Preterm Delivery are Doubled

After Abortion, Danish Women's Odds of Preterm Delivery are Doubled

Effects of Physical Activity on Preterm Birth

The authors conducted a cohort study of low income women to determine the effect of physical activity on the risk of preterm birth. Women were sampled prenatally from four clinic sites and were scheduled for delivery at the University of Maryland Medical Systems (UMMS). Women who delivered infants at UMMS but who had received no prenatal care were also eligible. Preterm delivery was defined as a delivery prior to 37 completed weeks gestation. After adjusting for confounders, the odds of preterm delivery were increased for women who climbed stairs > or = 10 times per day (odds ratio (OR) = 1.60, 95% confidence interval 1.05-2.46) and for women who engaged in purposive walking > or = 4 days per week (OR = 2.10, 95% CI 1.38-3.20). Leisure-time exercise (> or = 60 days in the first and second trimesters combined) had a protective effect on preterm delivery (OR = 0.51, 95% CI 0.27-0.95). Television viewing had a U-shaped relation with preterm delivery (ORs (95% CI): 42 hours, 3.05 (1.75-5.40)). While the results support current recommendations regarding leisure-time activities, activities of daily living appear to increase risk of preterm delivery among low income women. These findings and those for television watching warrant further investigation.

Low-to-Moderate Gestational Alcohol Use and Intrauterine Growth Retardation, Low Birthweight, and Preterm Delivery

Abstract PURPOSE: Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy. METHODS: This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988–1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birth weight. RESULTS: Mild drinking, defined as > 0.10 – 0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20 – 0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64 – 5.05) for light drinking and 2.96 (95% CI, 1.32 – 6.67) for mild-to-moderate alcohol consumption. CONCLUSIONS: Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

Low-to-moderate gestational alcohol use and intrauterine growth retardation, low birthweight, and preterm delivery

PURPOSE: Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy. METHODS: This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988–1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birth weight. RESULTS: Mild drinking, defined as > 0.10 – 0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20 – 0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64 – 5.05) for light drinking and 2.96 (95% CI, 1.32 – 6.67) for mild-to-moderate alcohol consumption. CONCLUSIONS: Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

EFFECT OF MATERNAL WORK ACTIVITY ON PRETERM BIRTH AND LOW BIRTH WEIGHT

The association of the prolonged standing required by certain jobs with the rate of preterm births and low birth weight deliveries was examined in New Haven, Connecticut, between 1980 and 1982. In a sample of 1,206 women, the rate of preterm births (births occurring less than 37 weeks from the last menstrual period) was higher among women with jobs requiring prolonged standing (7.7%) compared with those with sedentary (4.2%) or active jobs (2.8%). The odds of preterm delivery in the standing group was 2.72 (95% confidence interval of 1.24-5.95). A significant association between standing on the job and preterm birth was demonstrated when adjustment was made for the following variables in a logistic regression model: parity, smoking, education, caffeine use, marijuana use, race, gestational age at interview, and marital status. The low birth weight (less than 2,500 g) rate was higher among those in the standing group (5.5%) compared with those in the sedentary (4.0%) and active groups (4.0%), but this association was not significant when confounding factors were controlled.