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PubMed2003

Maternal asthma and risk of preterm delivery.

PURPOSE: We studied the relation between maternal history of asthma and preterm delivery. METHODS: The 312 preterm delivery cases, studied in aggregate, and in subgroups (spontaneous preterm labor, preterm premature rupture of membranes, medically induced preterm delivery), were compared with 424 randomly selected women who delivered at term. Maternal medical records provided information on maternal lifetime asthma status, pregnancy outcome, and sociodemographic characteristics. Using multivariate logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Maternal history of asthma was associated with an increased risk of preterm delivery overall (OR = 2.37; 95% CI 1.15-4.88). Analyses of preterm delivery sub-groups indicated that maternal history of asthma was associated with at least a doubling in risk of spontaneous preterm labor (OR = 2.35; 95% CI 0.84-6.58) and medically induced preterm delivery (OR = 2.69; 95% CI 1.11-6.53), though only the latter approached statistical significance. There was some evidence of a modest association between maternal asthma and risk of preterm premature rupture of membranes (OR = 1.63; 95% CI 0.50-5.33). CONCLUSIONS: These results support the hypothesis that maternal asthma is associated with an increased risk of preterm labor and delivery.

Adult↗
PubMed2002

Polymorphism in the interleukin-1 gene complex and spontaneous preterm delivery.

OBJECTIVE: We examined the association between preterm delivery and polymorphisms at position +3953 of the interleukin-1 beta gene (IL1B+3953) and in intron 2 of the interleukin-1 receptor antagonist gene (IL1RN). STUDY DESIGN: This was a case-control study that involved 52 pregnancies that resulted in spontaneous preterm delivery before 34 weeks of gestation and 197 pregnancies that resulted in birth at term. Polymorphisms were determined by polymerase chain reaction and restriction fragment length polymorphism analysis. RESULTS: Homozygous carriage of IL1B+3953 allele 1 by fetuses of African descent was associated with a risk of preterm delivery (P =.033). Fetuses of Hispanic descent that carried IL1RN allele 2 were found to be at an increased risk for preterm premature rupture of membranes and subsequent preterm delivery(P =.021; odds ratio, 6.5; 95% CI, 1.25-37.7). CONCLUSION: There are associations of spontaneous preterm delivery with the fetal carriage of IL1B+3953*1 and IL1RN*2 alleles in African and Hispanic populations, respectively.

Adult↗
PubMed2005

Does progesterone treatment influence risk factors for recurrent preterm delivery?

OBJECTIVE: To examine how demographic and pregnancy characteristics can affect the risk of recurrent preterm delivery and the how the effectiveness of progesterone treatment for prevention alters these relationships. METHODS: This was a secondary analysis of a randomized trial of 17alpha-hydroxyprogesterone caproate to prevent recurrent preterm delivery in women at risk. Associations of risk factors for preterm delivery (less than 37 completed weeks of gestation) were examined separately for the women in the 17alpha-hydroxyprogesterone caproate (n = 310) and placebo (n = 153) groups. RESULTS: Univariate analysis found that the number of previous preterm deliveries and whether the penultimate delivery was preterm were significant risk factors for preterm delivery in both the placebo and progesterone groups. High body mass index was protective of preterm birth in the placebo group. Multivariate analysis found progesterone treatment to cancel the risk of more than 1 previous preterm delivery, but not the risk associated with the penultimate pregnancy delivered preterm. Obesity was associated with lower risk for preterm delivery in the placebo group but not in the women treated with progesterone. CONCLUSION: The use of 17alpha-hydroxyprogesterone caproate in women with a previous preterm delivery reduces the overall risk of preterm delivery and changes the epidemiology of risk factors for recurrent preterm delivery. In particular, these data suggest that 17alpha-hydroxyprogesterone caproate reduces the risk of a history of more than 1 preterm delivery. LEVEL OF EVIDENCE: I.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1998

The value of transvaginal ultrasonographic examination of the uterine cervix in predicting preterm delivery in patients with preterm premature rupture of membranes.

The objective of this study was to compare the value of ultrasonographic assessment of the uterine cervix and amniotic fluid tests in the prediction of the interval from admission to delivery in patients with preterm premature rupture of membranes. Ninety-two patients admitted to the hospital for preterm premature rupture of membranes between 24 and 32 weeks of gestation underwent both transabdominal amniocentesis and transvaginal ultrasonographic evaluation of the uterine cervix. Amniotic fluid analyses included cultures for aerobic and anaerobic bacteria, mycoplasmas and ureaplasmas, white blood cell count and glucose and interleukin-6 determinations. The ultrasonographic variables evaluated were cervical length, presence of funneling and cervical index ((funnel length + 1)/cervical length). The outcome measure was the interval from admission to delivery. The median interval from admission to delivery was 4.5 days (range 0-36). An abnormal uterine cervix was associated with a short time interval (cervical length < or = 20 mm, median 2 days, range 0-14 vs. median 6 days, range 0-36; p < or = 0.0001; presence of funneling, median 3 days, range 1-31 vs. median 8 days, range 0-36; p < or = 0.001; cervical index > 0.50, median 2 days, range 0-7 vs. median 8 days, range 1-36; p < or = 0.0001). However, interleukin-6 concentration in the amniotic fluid was the best predictor of the interval from admission to delivery when compared to the ultrasonographic indices and to all the amniotic variables considered. Moreover, when a multiple model was applied, the cervical index significantly and independently improved the performance of interleukin-6 in the prediction of the interval from admission to delivery. These data suggest that the combined use of the amniotic fluid interleukin-6 assay and the cervical index in patients with preterm premature rupture of membranes provides a good prediction of the interval from admission to delivery, thus identifying a subgroup of patients at high risk of imminent delivery.

Adult↗
PubMed2004

Influence of inter-pregnancy interval on preterm delivery.

The influence of pregnancy spacing on preterm delivery (<37 weeks gestation) was examined in a group of mothers attending three Maternal and Child Health centres in three different districts in the city of Alexandria, Egypt between October 2001 and July 2002. All pregnant mothers attending the centres were interviewed or had their medical records reviewed. They were followed up until delivery and were questioned about current and past obstetric history and their medical history; their haemoglobin level was measured. The inter-pregnancy interval was calculated as the number of months between the delivery date of the women's last previous live infant and the date of the last menstrual period before the current pregnancy. There were 1202 pregnant women eligible for inclusion. The inter-pregnancy intervals were divided into five categories: <12, 12-36, 37-48, 49-60 and >60 months. We calculated the rates of preterm deliveries for each inter-pregnancy interval. Unadjusted odds ratios were estimated and stepwise logistic regression analysis was then used to adjust for all confounding factors. The rate of preterm delivery was 9.4%, and the lowest risk occurred in women who had an inter-pregnancy interval >60 months; 7.3% of those women gave birth to preterm infants. The rate of preterm delivery increased with increasing inter-pregnancy interval until 49-60 months; however, the association between inter-pregnancy interval and preterm delivery was not statistically significant whether using the crude or adjusted odds ratios.

Adult↗
PubMed2004

Factors associated with preterm delivery in women with type 1 diabetes: a cohort study.

OBJECTIVE: The reported rate of preterm delivery in women with type 1 diabetes ranges from 22 to 45%, but the reasons are unclear. The purpose of this study was to identify factors associated with preterm delivery in these women. RESEARCH DESIGN AND METHODS: We studied the influence of maternal and diabetes-related factors on the occurrence of preterm delivery in 168 single pregnancies occurring in 127 women with type 1 diabetes. Women with spontaneous or indicated preterm delivery were compared with those who delivered after 37 weeks of gestation using polytomous logistic regression. RESULTS: The overall rate of preterm delivery was 24%, fivefold higher than the French prematurity rate in single pregnancy. Preterm delivery was spontaneous in 9% and indicated in 15%. HbA1c > or =7% at delivery was associated with spontaneous preterm delivery (odds ratio [OR] 5.3 [95% CI 1.1-26.8]). Nulliparity (12.0 [2.3-64.1]), progression of nephropathy (7.7 [1.3-46.9]), preeclampsia (12.0 [3.1-47.1]), and HbA1c > or =7% (7.5 [1.5-37.9]) at delivery were all associated with indicated preterm delivery. Preterm delivery was associated with significant neonatal morbidity as the risks for neonatal hypoglycemia and respiratory distress syndrome were increased by three- to sixfold compared with the reference group. CONCLUSIONS: The rate of preterm delivery remains high in women with type 1 diabetes. Different factors were associated with spontaneous and indicated preterm delivery, respectively. Because poor glycemic control was a risk factor for both outcomes, part of preterm delivery might be preventable.

Adult↗
PubMed2005

The thyroid and pregnancy: a novel risk factor for very preterm delivery.

The major cause of neonatal mortality and morbidity is preterm delivery in general (< 37 completed weeks), and especially very preterm delivery (< 32 completed weeks). The objective of this study is to determine if either thyroid hormonal dysfunction and/or the presence of thyroid autoantibodies in the mother are associated with an increased risk of preterm and/or very preterm delivery. Data were collected prospectively and analyzed as a nested-case control study. There were 953 delivered gravidas enrolled between 1996 and 2002. Samples were collected at entry to care and stored at -70 degrees C. Cases included all women with preterm delivery (n = 124). Controls (n = 124) were randomly selected from among the 829 women who delivered at term (> 37 completed weeks). All samples were assessed for thyroid stimulating hormone, thyroperoxidase antibody, and thyroglobulin antibody. Gravidas with high thyrotropin (TSH) levels had a greater than threefold increase in risk of very preterm delivery. In some analyses, gravidas who tested positive for thyroglobulin antibody at entry to prenatal care also had a better than twofold increased risk of very preterm delivery. There were no significant associations between TSH level or thyroglobulin antibody positivity and the risk of moderately preterm delivery.

Adult↗
PubMed1992

Low birth weight and preterm delivery in relation to early-gestation vaginal bleeding and elevated maternal serum alpha-fetoprotein.

OBJECTIVE: To determine whether early-gestation vaginal bleeding and elevated maternal serum alpha-fetoprotein (MSAFP) are independent risk factors for adverse infant outcomes. METHODS: We conducted a cohort study of 201 women with an elevated MSAFP (at least 2.0 multiples of the median [MOM]) and a second-trimester ultrasound evaluation at Swedish Hospital Medical Center between January 1989 and March 1991, and 211 women with MSAFP levels below 2.0 MOM who had also undergone ultrasound evaluations during the same period. RESULTS: Stratified analyses demonstrated that early-gestation bleeding and elevated MSAFP were independent risk factors for the delivery of both preterm and low birth weight infants. Compared with women with no history of early-gestation bleeding or elevated MSAFP, women with early-gestation bleeding alone had a relative risk (RR) of preterm delivery of 4.3 (95% confidence interval [CI] 1.5-12.1); non-bleeders with elevated MSAFP had an RR of 4.6 (95% CI 1.9-10.9). A combined history of early-gestation bleeding and elevated MSAFP was associated with an almost sixfold increased risk of preterm delivery (RR 5.8; 95% CI 2.2-15.6). Analyses restricted to women with normal-appearing appearing placentas by second-trimester ultrasound evaluations yielded similar results. CONCLUSIONS: These findings support an earlier report documenting the independence of early-gestation bleeding and elevated MSAFP as predictors of adverse infant outcomes.

Cohort Studies↗
PubMed2006

Spontaneous preterm delivery in primiparous women at low risk in Denmark: population based study.

OBJECTIVES: To analyse trends in preterm delivery and the factors contributing to preterm delivery in Denmark. To construct a standard population at low risk (white European, 20-40 years of age, with a singleton spontaneous pregnancy) and describe the changes in this population so that time trends can be compared internationally. DESIGN: Population based study. PARTICIPANTS: 99.8% of all deliveries in Denmark, 1995-2004. MAIN OUTCOME MEASURES: Proportion of babies born at less than 37 weeks' completed gestation for each year in the overall population and in a standard population at low risk. RESULTS: Overall, the proportion of preterm deliveries increased by 22% from 1995 to 2004. During the same period, known risk factors for preterm delivery such as in vitro fertilisation, multiple pregnancies, and elective deliveries also increased, and logistic regression analyses showed that these factors were associated with an increased risk of preterm delivery. Spontaneous preterm deliveries in primiparous women at low risk rose 51% (from 3.8% to 5.7%) during this time compared with 20% (2.7% to 3.2%) in multiparous women at low risk. CONCLUSIONS: The overall proportion of preterm deliveries increased significantly from 1995 to 2004 and primiparity and multiple birth were the most important contributing factors. The rise in spontaneous preterm deliveries in the standard population of primiparous women at low risk was greater than in the total population.

Adult↗
PubMed1983

Seasonal patterns in perinatal mortality and preterm delivery.

An investigation of possible seasonal patterns in preterm delivery and perinatal mortality utilized linked birth, infant death, and fetal death records from Minnesota for the years 1967-1973. Data included over 400,000 white singleton live births and stillbirths of 29 or more weeks completed gestation. Composite monthly cohorts of ongoing pregnancies were constructed for each month of the year and the probability of a preterm delivery and/or perinatal death was estimated. A statistically significant increase in the probability of a preterm delivery or perinatal death occurred during July, August, and September. The probability of a preterm delivery ranged from a low of 55 per 1000 pregnancies at risk in April to a high of over 59 per 1000 in July and August. In addition, although each assigned cause of death group showed a similar pattern, perinatal deaths due to infection in the mother or fetus showed a standardized mortality ratio of 65 in May and 155 in August and September, while the ratios of all other causes combined ranged from 94 to 108. Fetal deaths reported as having occurred before labor began showed a seasonal pattern nearly identical with that for all perinatal deaths, while those occurring during labor showed no seasonal pattern. The findings are consistent with published evidence that environmental factors likely involving ascending infections may play a larger role in preterm delivery and perinatal mortality than has been generally recognized.

Epidemiologic Methods↗
PubMed2005

Previous induced abortions and the risk of very preterm delivery: results of the EPIPAGE study.

OBJECTIVES: To evaluate the risk of very preterm birth (22-32 weeks of gestation) associated with previous induced abortion according to the complications leading to very preterm delivery in singletons. DESIGN: Multicentre, case-control study (the French EPIPAGE study). SETTING: Regionally defined population of births in France. SAMPLE: The sample consisted of 1943 very preterm live-born singletons (< 33 weeks of gestation), 276 moderate preterm live-born singletons (33-34 weeks) and 618 unmatched full-term controls (39-40 weeks). METHODS: Data from the EPIPAGE study were analysed using polytomous logistic regression models to control for social and demographic characteristics, lifestyle habits during pregnancy and obstetric history. The main mechanisms of preterm delivery were classified as gestational hypertension, antepartum haemorrhage, fetal growth restriction, premature rupture of membranes, idiopathic preterm labor and other causes. MAIN OUTCOME MEASURES: Odds ratios for very preterm birth by gestational age and by pregnancy complications leading to preterm delivery associated with a history of induced abortion. RESULTS: Women with a history of induced abortion were at higher risk of very preterm delivery than those with no such history (OR + 1.5, 95% CI 1.1-2.0); the risk was even higher for extremely preterm deliveries (< 28 weeks). The association between previous induced abortion and very preterm delivery varied according to the main complications leading to very preterm delivery. A history of induced abortion was associated with an increased risk of premature rupture of the membranes, antepartum haemorrhage (not in association with hypertension) and idiopathic spontaneous preterm labour that occur at very small gestational ages (< 28 weeks). Conversely, no association was found between induced abortion and very preterm delivery due to hypertension. CONCLUSION: Previous induced abortion was associated with an increased risk of very preterm delivery. The strength of the association increased with decreasing gestational age.

Abortion, Induced↗
PubMed2006

Combined effects of prepregnancy body mass index and weight gain during pregnancy on the risk of preterm delivery.

BACKGROUND: The association between excessive gestational weight gain and preterm delivery is unclear, as is the association between low gestational weight gain and preterm delivery among overweight and obese women. METHODS: Using data from the Pregnancy Risk Assessment Monitoring System in 21 states, we estimated the risk of very (20-31 weeks) and moderately (32-36 weeks) preterm delivery associated with a combination of prepregnancy body mass index (BMI) and gestational weight gain among 113,019 women who delivered a singleton infant during 1996-2001. We categorized average weight gain (kilograms per week) as very low (<0.12), low (0.12-0.22), moderate (0.23-0.68), high (0.69-0.79), or very high (>0.79). We categorized prepregnancy BMI (kg/m) as underweight (<19.8), normal (19.8-26.0), overweight (26.1-28.9), obese (29.0-34.9), or very obese (>or=35.0). We examined associations for all women and for all women with no complications adjusting for covariates. RESULTS: There was a strong association between very low weight gain and very preterm delivery that varied by prepregnancy BMI, with the strongest association among underweight women (adjusted odds ratio = 9.8; 95% confidence interval = 7.0-13.8) and the weakest among very obese women (2.3; 1.8-3.1). Very low weight gain was not associated with moderately preterm delivery for overweight or obese women. Women with very high weight gain had approximately twice the odds of very preterm delivery, regardless of prepregnancy BMI. CONCLUSIONS: This study supports concerns about very low weight gain during pregnancy, even among overweight and obese women, and also suggests that high weight gain, regardless of prepregnancy BMI, deserves further investigation.

Adolescent↗
PubMed2003

Prevention of recurrent preterm delivery by 17 alpha-hydroxyprogesterone caproate.

BACKGROUND: Women who have had a spontaneous preterm delivery are at greatly increased risk for preterm delivery in subsequent pregnancies. The results of several small trials have suggested that 17 alpha-hydroxyprogesterone caproate (17P) may reduce the risk of preterm delivery. METHODS: We conducted a double-blind, placebo-controlled trial involving pregnant women with a documented history of spontaneous preterm delivery. Women were enrolled at 19 clinical centers at 16 to 20 weeks of gestation and randomly assigned by a central data center, in a 2:1 ratio, to receive either weekly injections of 250 mg of 17P or weekly injections of an inert oil placebo; injections were continued until delivery or to 36 weeks of gestation. The primary outcome was preterm delivery before 37 weeks of gestation. Analysis was performed according to the intention-to-treat principle. RESULTS: Base-line characteristics of the 310 women in the progesterone group and the 153 women in the placebo group were similar. Treatment with 17P significantly reduced the risk of delivery at less than 37 weeks of gestation (incidence, 36.3 percent in the progesterone group vs. 54.9 percent in the placebo group; relative risk, 0.66 [95 percent confidence interval, 0.54 to 0.81]), delivery at less than 35 weeks of gestation (incidence, 20.6 percent vs. 30.7 percent; relative risk, 0.67 [95 percent confidence interval, 0.48 to 0.93]), and delivery at less than 32 weeks of gestation (11.4 percent vs. 19.6 percent; relative risk, 0.58 [95 percent confidence interval, 0.37 to 0.91]). Infants of women treated with 17P had significantly lower rates of necrotizing enterocolitis, intraventricular hemorrhage, and need for supplemental oxygen. CONCLUSIONS: Weekly injections of 17P resulted in a substantial reduction in the rate of recurrent preterm delivery among women who were at particularly high risk for preterm delivery and reduced the likelihood of several complications in their infants.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed2004

Treatment for cervical intraepithelial neoplasia and risk of preterm delivery.

CONTEXT: It is unclear whether treatments for cervical intraepithelial neoplasia (CIN) increase the subsequent risk of preterm delivery. Most studies have lacked sufficient sample size, mixed heterogeneous subtypes of preterm delivery, and failed to control for confounding factors. OBJECTIVE: To determine whether cervical laser and loop electrosurgical excision procedure (LEEP) treatments increase risk of preterm delivery and its subtypes. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study conducted among women evaluated at a colposcopy clinic serving Auckland, New Zealand (1988-2000), comparing delivery outcomes of untreated women (n = 426) and those treated (n = 652) with laser conization, laser ablation, or LEEP. Record linkage using unique health identifiers identified women who had subsequent deliveries. MAIN OUTCOME MEASURES: Total preterm delivery and its subtypes, spontaneous labor and premature rupture of membranes before 37 weeks' gestation (pPROM). RESULTS: The overall rate of preterm delivery was 13.8%. The rate of pPROM was 6.2% and the rate of spontaneous preterm delivery was 3.8%. Analyses showed no significant increase in risk of total preterm delivery (adjusted relative risk [aRR], 1.1; 95% confidence interval [CI], 0.8-1.5) or spontaneous preterm delivery (aRR, 1.3; 95% CI, 0.7-2.6) for any treatment. Risk of pPROM was significantly increased following treatment with laser conization (aRR, 2.7; 95% CI, 1.3-5.6) or LEEP (aRR, 1.9; 95% CI, 1.0-3.8), but not laser ablation (aRR, 1.1; 95% CI, 0.5-2.4). Moreover, risk of pPROM and total preterm delivery increased significantly with increasing height of tissue removed from the cervix in conization. Women in the highest tertile of cone height (> or =1.7 cm) had a greater than 3-fold increase in risk of pPROM compared with untreated women (aRR, 3.6; 95% CI, 1.8-7.5). CONCLUSIONS: LEEP and laser cone treatments were associated with significantly increased risk of pPROM. Careful consideration should be given to treatment of CIN in women of reproductive age, especially when treatment might reasonably be delayed or targeted to high-risk cases.

Cervix Uteri↗
PubMed2006

Primary dysmenorrhea and risk of preterm delivery.

Little is known about the mechanism and biochemical pathway of preterm delivery. Some drugs used to treat preterm labor are also useful for the treatment of primary dysmenorrhea. This study attempted to evaluate the association between primary dysmenorrhea and preterm delivery from an epidemiological perspective. A nested case-control study was conducted; 329 singleton preterm delivery cases were investigated, in aggregate and in subgroups (spontaneous preterm labor and preterm premature rupture of membranes). Concurrently, 329 singleton gravid women with term delivery served as controls. Medical charts and records provided information about the maternal history of dysmenorrhea, index pregnancy outcome, and demographic characteristics. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the multiple logistic regression method. Gravid women with a history of primary dysmenorrhea had no more risk of preterm delivery than those without a history of primary dysmenorrhea (adjusted OR, 1.16; 95% CI, 0.95 to 2.19; p=0.37). However, for subgroup analysis, gravid women with severe primary dysmenorrhea were associated with an adjusted 2.73-fold risk of spontaneous preterm delivery (95% CI, 1.49 to 4.95; p=0.02), and with an adjusted 1.51-fold risk of preterm premature rupture of membranes (95% CI, 0.68 to 3.22; p=0.31). Severe primary dysmenorrhea is associated with an increased risk of spontaneous preterm delivery. A common pathophysiologic pathway may exist between these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.

Adult↗
PubMed2004

Ultrasonographic cervical length measurement is not a better predictor of preterm delivery than digital examination in a population of patients with idiopathic preterm labor.

OBJECTIVE: To compare digital and ultrasonographic cervical examination for the prediction of preterm delivery in patients hospitalized for preterm labor. STUDY DESIGN: Fifty-nine patients were included. The Bishop score was evaluated upon admission, weeks gestational age. Ultrasonographic measurement of cervical length was done within 24h after entry. Delivery before 37 weeks gestational age was the primary endpoint. Attending obstetricians were blinded to the results of echography. RESULTS: Preterm delivery rate was 39% (23/59). The risk of preterm delivery was significantly increased when the Bishop score was greater than or equal to 6 (OR = 4.45 [1.41-14.01]) or when ultrasonographic cervical length was less than or equal to 27 mm (OR = 4.04 [1.32-12.3]), but digital examination was the only independent risk factor in multivariate analysis. Sensitivity, specificity, positive and negative predictive value for digital examination and ultrasonography were respectively 74, 61, 55 and 79%, 70, 64, 55 and 77%. Combination of digital examination and ultrasonography did not yield better results. CONCLUSION: In our series, prediction of preterm delivery was not improved by ultrasonography compared to digital examination. The size of the cervical shift observed in most patients hospitalized for preterm labor may render ultrasonography less relevant in identifying patients anticipated to deliver prematurely.

Adult↗
PubMed2001

Association between colonization with group B streptococci during pregnancy and preterm delivery among Danish women.

OBJECTIVE: We studied the relationship between group B streptococcal colonization and preterm delivery. STUDY DESIGN: In this prospective study at a single hospital in Odense, Denmark, cervicovaginal cultures were obtained at < or = 24 weeks' gestation from all the women, at delivery from women with preterm deliveries, and from a random sample of women delivering at term. RESULTS: In 2846 singleton births, there was no significant association between group B streptococcal colonization at <or = 24 weeks' gestation and preterm birth. After adjustment for the risk factors for preterm delivery, more women with preterm delivery (12/84, 14%) were colonized at delivery with group B streptococci than women with term deliveries (22/300, 7%; adjusted odds ratio, 3.0; 95% confidence interval, 1.4-6.8). Group B streptococcal colonization at < or = 24 weeks' gestation and at delivery was significantly less likely to occur in the presence of normal vaginal flora. CONCLUSION: Group B streptococcal colonization at delivery, but not at < or = 24 weeks' gestation, was associated with preterm delivery.

Adult↗
PubMed1986

Ethnic differences in preterm and very preterm delivery.

Ethnic differences in preterm (less than 37 weeks) and very preterm (less than 33 weeks) delivery were evaluated in a prospective cohort of 28,330 women. Blacks had the highest rate of preterm and very preterm delivery, followed by Mexican-Americans, Asians, and Whites. Adjustment for maternal age, education, marital status, employment, parity, number of previous spontaneous or induced abortions, smoking and drinking during pregnancy, infant sex, and gestational age at initiation of prenatal care resulted in the following odds ratios for preterm delivery: 1.79 (1.55-2.08) for Blacks, 1.40 (1.19-1.63) for Mexican-Americans, 1.40 (1.16-1.69) for Asians, and 1.00 for Whites. The corresponding odds ratios for very preterm delivery were 2.35 (1.72-3.22) for Blacks, 1.31 (0.88-1.94) for Mexican-Americans, 1.10 (0.67-1.83) for Asians, and 1.00 for Whites. Exclusion of cases of premature rupture of membranes, placenta previa, and abruptio placenta did not explain the large ethnic differences. Although Whites and Mexican-Americans had similar birthweight distributions, Mexican-Americans had an increased risk for preterm delivery. Fifty-five per cent of low birthweight babies in Kaiser were preterm and this fraction did not vary substantially by ethnic group.

Adult↗