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PubMed2006

Adenomyosis and risk of preterm delivery.

OBJECTIVE: To evaluate the risk of preterm delivery in patients with adenomyosis. DESIGN: A 1:2 nested case-control study. SETTING: Tertiary-care institution. POPULATION: A base cohort population of 2138 pregnant women who attended routine prenatal check-up between July 1999 and June 2005. METHODS: From this base cohort population, gravid women with singleton pregnancy who delivered prior to the completion of 37 weeks of gestation were identified and formed the study group. Singleton gravid women who had term delivery and who matched with age, body mass index, smoking, and status of previous preterm delivery were recruited concurrently and served as control group. Preterm delivery cases were further divided into spontaneous preterm delivery and preterm premature rupture of membranes (PPROM) cases. MAIN OUTCOME MEASURES: Risk analysis of preterm delivery between gravid women with and without adenomyosis. RESULTS: One-hundred and four preterm delivery case subjects and 208 control subjects were assessed. Overall, gravid women with adenomyosis were associated with significantly increased risk of preterm delivery (adjusted odds ratio 1.96, 95% CI 1.23-4.47, P=0.022). For subgroup analysis, gravid women with adenomyosis had an adjusted 1.84-fold risk of spontaneous preterm delivery (95% CI 1.32-4.31, P=0.012) and an adjusted 1.98-fold risk of PPROM (95% CI 1.39-3.15, P=0.017). CONCLUSIONS: Gravid women with adenomyosis were associated with increased risk of both spontaneous preterm delivery and PPROM. A common pathophysiological pathway may exist in these two disorders. Further in-depth biochemical and molecular studies are necessary to explore this phenomenon.

Case-Control Studies↗
PubMed2003

History of fetal loss and other adverse pregnancy outcomes in relation to subsequent risk of preterm delivery.

OBJECTIVE: To evaluate the association between maternal reproductive history 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, moderate preterm delivery [gestational age at delivery 34-36 weeks], and very preterm delivery [gestational age at delivery <34 weeks]), were compared with 424 randomly selected women who delivered at term. Maternal medical records provided information on maternal reproductive history, pregnancy outcome, as well as sociodemographic characteristics. Using multivariate logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: A history of 2+ miscarriages was (OR = 2.2; 95% CI 1.2-3.9), but a history of 2+ prior induced abortions (OR = 1.2; 95% CI 0.7-2.0) was not, associated with preterm delivery in the index pregnancy. Analyses of preterm delivery subgroups indicated that a history of 2+ miscarriages was associated with an increased risk of spontaneous preterm labor (OR = 2.6; 95% CI 1.2-2.8), preterm premature rupture of membrane (OR = 1.8; 95% 0.7-4.4), and medically induced preterm delivery (OR = 1.9; 95% CI 0.8-4.2), though only the former approached statistical significance. Excess risk of preterm delivery was associated with maternal prior history of delivering a stillborn infant (OR = 10.7), a prior history of delivering a newborn that later died during the neonatal period (OR = 3.2), and a prior history of having a pregnancy complicated by spontaneous preterm delivery (OR = 6.0). Generally these associations were evident for each subgroup of preterm delivery, though inferences were often hindered by our relatively small sample size. CONCLUSIONS: These results support the hypothesis that maternal adverse reproductive history is associated with an increased risk of preterm labor and delivery.

Abortion, Induced↗
PubMed2002

Periodontal disease increases the risk of preterm delivery among preeclamptic women.

BACKGROUND: Preterm births are a major cause of neonatal morbidity and mortality, and represent an important public health issue. About 30% of preterm births are due to medical conditions of the mother or the fetus, among "which preeclampsia plays a major role. We have previously reported that maternal periodontal disease enhances the risk for preterm delivery and preeclampsia. Our current objective was to determine whether maternal periodontal disease increases the risk for preterm delivery among preeclamptic women. METHODS: Women were enrolled prior to their twenty-sixth week of gestation. Periodontal status was assessed at baseline and defined as healthy, mild, or moderate/severe. Repeat examinations were performed at delivery to assess changes in periodontal status. RESULTS: A cohort of 1,020 women was studied, 47 of whom had preeclampsia. A strong association between periodontal disease status at enrollment and rate of premature delivery was observed among preeclamptic women after adjusting for the major risk factors for preterm delivery, including maternal race; age; marital status; WIC (women, infants, children program) or food stamps; insurance; previous preterm delivery; and chorioamnionitis. Among preeclamptic women, 49.3% with mild periodontal disease and 82.6% with moderate to severe disease delivered preterm (hazard ratios [HR] 4.11 and 11.0, respectively). Periodontal disease worsening during pregnancy in preeclamptic women was also associated with an increased risk of preterm births (HR 8.44). CONCLUSION: These results suggest that mothers with preeclampsia may be at greater risk for preterm delivery if periodontal disease is present early in pregnancy or progresses during pregnancy.

Female↗
PubMed2002

Maternal second-trimester serum ferritin concentrations and subsequent risk of preterm delivery.

We studied the relationship between maternal second-trimester serum ferritin concentrations and preterm delivery. The 312 preterm delivery cases, studied in aggregate and in subgroups [spontaneous preterm labour, preterm premature rupture of membranes, medically induced preterm delivery, moderate preterm delivery (gestational age at delivery 34-36 weeks) and very preterm delivery (gestational age at delivery <34 weeks)] were compared with 424 randomly selected women who delivered at term. Maternal ferritin concentrations, measured in serum collected at 17 weeks gestation on average, was determined using a two-site chemiluminometric immunoassay. Using multiple logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals [CI]. Elevation in maternal second-trimester ferritin was weakly associated with the risk of preterm delivery overall. After adjusting for possible confounding by maternal age, race/ethnicity, parity, Medicaid payment status and smoking during the index pregnancy, the OR for extreme quartiles (>64.5 vs. <26.0 ng/mL) of ferritin was 1.3 [95% CI 0.8, 2.1]. Stratified analyses indicated that elevated maternal serum ferritin was associated with an increased risk of preterm premature rupture of membranes (OR = 2.1; 95% CI 1.1, 4.1), but not with spontaneous preterm labour (OR = 0.9; 95% CI 0.4, 1.7) or medically induced preterm delivery (OR = 1.1; 95% CI 0.6, 2.0). The relationship between elevated maternal second-trimester serum ferritin concentrations and preterm delivery was strongest for spontaneous very preterm deliveries (<34 weeks gestation). Women with ferritin concentrations in the highest decile (>96 ng/mL) experienced a 2.7-fold increased risk of delivering before 34 completed weeks, compared with women with concentrations <26.0 ng/mL. These results are consistent with some previous reports, and further underline the potential for heterogeneity in the aetiology of preterm delivery.

Adult↗
PubMed1995

Fetal growth and the etiology of preterm delivery.

OBJECTIVE: To confirm that preterm delivery is associated with fetal growth restriction (FGR), and to determine if the various etiologies of preterm delivery are associated with the same degree and type of FGR. METHODS: Two hundred ninety young, primarily minority gravidas who had routine initial ultrasound examinations also had subsequent ultrasound examinations at 32 weeks' gestation. Fetal growth characteristics were compared between preterm (less than 37 weeks' gestation) and term deliveries, and among preterm deliveries with medical or obstetric indications, premature rupture of membranes (PROM), and spontaneous preterm labor. RESULTS: Forty-six infants (15.9%) were born preterm. At 32 weeks' gestation, all fetuses later delivered preterm were already smaller than fetuses later delivered at term (P < .05) for all dimensions: head circumference (HC), abdominal circumference (AC), biparietal diameter (BPD), and femur length (FL). However, after stratifying by cause of preterm delivery for those fetuses later delivered for medical or obstetric indications, we found that only AC was decreased (P < .01) and that the HC-AC ratio was elevated (asymmetric FGR). Neonates delivered after unsuccessfully treated PROM or preterm labor were symmetrically smaller in all characteristics (HC, AC, BPD, and FL). CONCLUSION: By 32 weeks' gestation, fetuses later delivered preterm are already significantly smaller than fetuses later delivered at term. However, when stratified by the etiology of preterm delivery, infants delivered preterm for medical or obstetric indications had asymmetric growth patterns, which suggests a growth failure late in pregnancy. Infants delivered preterm after PROM or after failed or no tocolysis for spontaneous preterm labor were proportionately smaller, implying an overall slowing of growth that may originate early in pregnancy and possibly demonstrate a more chronic stress.

Adult↗
PubMedDate not supplied

Rates of and factors associated with recurrence of preterm delivery.

CONTEXT: Information about risk of recurrent preterm delivery is useful to clinicians, researchers, and policy makers for counseling, generating etiologic leads, and measuring the related public health burden. OBJECTIVES: To identify the rate of recurrence of preterm delivery in second pregnancies, factors associated with recurrence, and the percentage of preterm deliveries in women with a history of preterm delivery. DESIGN AND SETTING: Population-based cohort study of data from birth and fetal death certificates from the state of Georgia between 1980 and 1995. SUBJECTS: A total of 122 722 white and 56174 black women with first and second singleton deliveries at 20 to 44 weeks' gestation. MAIN OUTCOME MEASURE: Length of gestation (categorized as 20-31, 32-36, or > or =37 weeks) at second delivery compared with length of gestation at first delivery, by age and race. RESULTS: Most women whose first delivery was preterm subsequently had term deliveries. Of 1023 white women whose first delivery occurred at 20 to 31 weeks, 8.2% (95% confidence interval [CI], 6.6%-10.1%) delivered their second birth at 20 to 31 weeks and 20.1% (95% CI, 17.7%-22.8%) at 32 to 36 weeks. Of 1084 comparable black women, 13.4% (95 % CI, 11.4%-15.6%) delivered at 20 to 31 weeks and 23.4% (95% CI, 20.9%-26.1%) delivered at 32 to 36 weeks. Among women whose first delivery occurred at 32 to 36 weeks, all corresponding rates were lower than those whose first birth was at 20 to 31 weeks; the rates of second birth at 20 to 31 weeks were substantially lower (for white women, 1.9% [95% CI, 1.7%-2.2%]; for black women, 3.8% [95% CI, 3.4%-4.2%]). Compared with women aged 20 to 49 years at their second delivery, women younger than 18 years had twice the risk of recurrence of delivery at 20 to 31 weeks. Of all second deliveries at 20 to 31 weeks, 29.4% for white women and 37.8% for black women were preceded by a preterm delivery. CONCLUSIONS: Our data suggest that recurrence of preterm delivery contributes a notable portion of all preterm deliveries, especially at the shortest gestations.

Adolescent↗
PubMed2004

Risk factors for recurrent preterm delivery.

OBJECTIVE: To identify risk factors for recurrent preterm delivery among primiparous women with previous preterm delivery. STUDY DESIGN: A retrospective case-control study was designed: 152 primiparous women who delivered preterm (22-36 weeks) were divided into two groups: 81 had a second preterm delivery (study group) and 71 had a second-term delivery (control group). Exclusion criteria were induced preterm delivery, hydramnions and multiple gestations. RESULTS: Comparing second preterm delivery before 34 weeks (n = 36) to the second delivery of the control group, higher rates of hospitalization due to preterm labor were noted in the study versus the control group (52.8% versus 16.9%,P = 0.001). The interval between pregnancies was shorter in the study subgroup, before 34 weeks gestational age, versus the controls (20.1 +/-15.7 months versus 28.9 +/- 18.7 months, P = 0.011). Multiple regression analyses, adjusted for confounding variables, found the occurrence of preterm labor and short interval between pregnancies, especially up to 12 months, as independent risk factors for the recurrence of preterm delivery (OR = 4.98; P , 0.001; OR = 5.13; P = 0.007, respectively). CONCLUSION: When adjusted for confounding variables, short interval between pregnancies is an independent risk factor for recurrent preterm delivery.

Adult↗
PubMed2005

Are amniotic fluid C-reactive protein and glucose levels, and white blood cell counts at the time of genetic amniocentesis related with preterm delivery?

OBJECTIVE: To compare women with spontaneous preterm delivery before 37 weeks and women who delivered at term with respect to amniotic fluid C-reactive protein (CRP), glucose levels, and white blood cell counts at the time of genetic amniocentesis. STUDY DESIGN: The study was conducted on 216 pregnant women who underwent genetic amniocentesis between the 15th and 18th weeks of gestation at Baskent University Obstetrics and Gynecology Department. All patients were followed until delivery for the occurrence of pregnancy complication. Indications for amniocentesis included abnormal triple test results showing increased risk for Down's syndrome, advanced maternal age and sonographic findings indicative for chromosomal abnormalities. The samples were carried immediately to the laboratory for cytogenetic and biochemical examination. Women with spontaneous preterm delivery before 37 weeks (n = 20) and those who delivered at term (n = 196) were compared with respect to some maternal and infant characteristics, amniotic fluid C-reactive protein, glucose levels, and amniotic fluid white blood cell counts. RESULTS: During the study period 244 patients underwent amniocentesis. A chromosomal abnormality was present in 11 patients. 1 patient had a spontaneous pregnancy loss within 3 weeks after the procedure and 16 patients were delivered for fetal or maternal indications (preeclampsia, fetal growth restriction, placenta previa). The remaining 216 women were included in the study and investigated for the risk of preterm delivery. The prevalence of spontaneous preterm delivery before 37 weeks was 9.3% (20/216). There were no significant differences between the preterm delivery and the term delivery groups with respect to C-reactive protein levels and white blood cell counts. Mean amniotic glucose levels were significantly lower in the preterm delivery group (P<0.05). Amniotic fluid glucose levels of < or = 46 mg/dL had a sensitivity of 100% and NPV of 100%. CONCLUSION: Amniotic fluid glucose levels at the time of genetic amniocentesis are lower in women with spontaneous preterm delivery before 37 weeks compared to those who delivered at term. Amniotic fluid glucose levels of < or = 46 mg/dL at the time of genetic amniocentesis may be more sensitive, cheaper and have higher negative predictive value than C-reactive protein levels and white blood cell counts for the prediction of patients in spontaneous preterm labor. The greatest benefit of amniotic fluid glucose testing might be when the physician judges the patient to be at low risk for preterm delivery.

Amniocentesis↗
PubMed2000

Chlamydia trachomatis seropositivity is associated both with stillbirth and preterm delivery.

The cause of stillbirth and preterm delivery is often unknown. We studied the prevalence of Chlamydia trachomatis antibodies in mothers with stillbirth and preterm labor. Serum specimens from 72 mothers with stillbirth after the 21st gestational week, and from 48 mothers with preterm delivery between gestational weeks 23 and 29, both from the greater Helsinki area, and cord blood from 96 consecutive liveborn deliveries at the Department of Obstetrics and Gynecology, the University of Helsinki, were studied for antibodies to C. trachomatis immunotypes CJHI, GFK and BED by microimmunofluorescence test. The prevalence of C. trachomatis antibodies was highest, 33.3%, in mothers with stillbirth, 18.8% in mothers with preterm delivery, and 10.4% in cord blood. The IgM seropositivity rate was high among mothers with preterm delivery (8.3%). We conclude that C. trachomatis IgG antibodies are frequently detected in sera from mothers with stillbirth, suggesting past infection, while mothers with preterm delivery often have serum IgM antibodies, suggesting of acute infection.

Acute Disease↗
PubMed1993

Levels of insulin-like growth factor-I and insulin-like growth factor-binding protein-1 in pregnancy with preterm delivery.

OBJECTIVE: To investigate the relationship between preterm delivery and maternal serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-1 (IGFBP-1) levels. DESIGN: A study over a 12 month period in which all samples were collected according to a pre-set protocol. SETTING: St. Bartholomew's Hospital, London. SUBJECTS: Thirty-eight nonpregnant adult females, 456 pregnant women at various gestational ages, 84 women with average-for-gestational-age babies at term delivery, and 49 pregnant women with preterm delivery (44 with singleton pregnancy and five with twin pregnancy). MAIN OUTCOME MEASURES: Serum IGF-I and IGFBP-1 levels were determined by radioimmunoassay. RESULTS: Serum IGF-I concentrations increased as pregnancy progressed. In the third trimester, serum IGF-I levels in singleton preterm deliveries were lower than those in normal pregnancies, and IGFBP-1 concentrations were higher than those in normal pregnancies. This phenomenon was not obvious in the second trimester. Maternal circulating IGFBP-1 levels were correlated inversely with birthweight in women with singleton preterm delivery. CONCLUSIONS: Neither IGF-I nor IGFBP-1 appears to play a significant role in preterm delivery since maternal serum IGF-I and IGFBP-1 levels are similar in preterm and term deliveries.

Birth Weight↗
PubMed2002

Risk factors for preterm delivery in patients demonstrating sonographic evidence of premature dilation of the internal os, prolapse of the membranes in the endocervical canal and shortening of the distal cervical segment by second trimester ultrasound.

OBJECTIVE: To investigate the outcomes and risk factors associated with the second trimester sonographic findings of premature dilation of the internal cervical os, prolapse of the membranes into the endocervical canal and shortening of the distal segment. STUDY DESIGN: Retrospective chart review to identify patients who met the following criteria: (i) gestational age between 16 and 24 weeks; (ii) a vaginal probe ultrasound documenting dilatation of the internal os, prolapsed membranes into the endocervical canal but not extending beyond the external os, and a shortened distal cervix; and (iii) no evidence of increased uterine activity METHODS: Sonographic measurements obtained included: (i) the width of the internal os dilation; (ii) the depth of membranes prolapsed into endocervix (funneling); (iii) the distal cervical length; and (iv) the total cervical length. Patients were stratified into two groups according to gestational age at delivery: the preterm group (< 34 weeks) and the near-term group (> or = 34 weeks). RESULTS: Thirty-seven patients had complete records for analysis and their pregnancies resulted in 47 live births. Eighteen patients were stratified to the near term group and 19 were stratified to the preterm group. There were no stillborn infants and 10 neonatal deaths. Ten patients received cerclage and seven patients delivered at < 34 weeks gestational age. Risk factors found to be significant for preterm delivery included a gestational age at diagnosis of < or = 20 weeks gestation (p = 0.03), dilatation of the internal os > 1.3 cm (p = 0.04), and a composite Benham score > or = 1.0 (p = 0.02). CONCLUSIONS: The sonographic findings of premature dilatation of the internal os, prolapse of the membranes into the endocervical canal and shortening of the distal cervix are associated with a high rate of delivery < 34 weeks (51%) and neonatal death (27%).

Adult↗
PubMed1997

Calcium-phosphorus-magnesium homeostasis in women with threatened preterm delivery.

OBJECTIVE: The effect of threatened preterm delivery on calcium, phosphorus, magnesium homeostasis in the third trimester of pregnancy was investigated. METHODS: Serum concentrations of total and ionized calcium, inorganic phosphorus, magnesium, total protein, albumin, total estrogens and human placental lactogen were determined in women with threatened preterm delivery at 29-36 weeks of gestation (the studied group) and in women with uncomplicated pregnancy of the same duration (the control group). Additionally, activities of total alkaline phosphatase and heat-stable alkaline phosphatase fraction were measured. RESULTS: Patients of the studied group compared to the control group showed decreased concentration of total calcium (2.17 +/- 0.09 vs. 2.28 +/- 0.13 mmol/l, P < 0.0005), inorganic phosphorus (1.13 /- 0.27 vs. 1.32 +/- 0.23 mmol/l, P < 0.001) and magnesium (0.64 +/- 0.07 vs. 0.70 +/- 0.10 mmol/l, P < 0.003); they also demonstrated decreased activity of total alkaline phosphatase (70.8 +/- 23.2 vs. 81.9 +/- 14.9 IU/l, P < 0.01) and its heat-stable fraction (30.2 +/- 15.6 vs. 59.6 +/- 14.9 IU/l, P < 0.001). In the studied group no difference was found in concentrations of investigated ions and enzymes between women who delivered at term and women who delivered prematurely. Patients with threatened preterm delivery showed serum deficiency of total calcium, phosphorus and magnesium which might be related to premature uterine contractility but does not predict premature labor by week 36 of gestation (66% of patients delivered at term). CONCLUSION: The deficiency of minerals and lowered activity of total alkaline phosphatase is observed in women with threatened preterm delivery. Laboratory tests of calcium-phosphorus-magnesium homeostatsis have limited predictive value in regard to the term of delivery in women with threatened preterm delivery.

Alkaline Phosphatase↗
PubMed1985

The association of chorioamnionitis with preterm delivery.

To ascertain what proportion of preterm deliveries are attributable to the association with chorioamnionitis, the authors examined prospectively the placentas from all 2774 women who delivered at the Johns Hopkins Hospital during 1980. The incidence of preterm delivery was 5.4% (110 of 2027) when neither chorioamnionitis nor premature rupture of membranes (PROM) was present, 11.9% (29 of 243) when chorioamnionitis was present without PROM, and 56.7% (51 of 90) when both chorioamnionitis and PROM were present (P less than .05). Only 27 of 333 cases of histopathologic chorioamnionitis or 8.1% had maternal antepartum fever, and only 11 of 333 or 3.3% had neonatal sepsis. Using logistic regression analysis to control for confounding variables, approximately 25% of the preterm deliveries were statistically attributable to histopathologic chorioamnionitis, occurring either alone or in association with PROM. In light of the infrequency with which histopathologic chorioamnionitis is clinically evident, the strong relationship between histopathologic chorioamnionitis and preterm delivery suggests that occult antepartum infection of the genital tract is an important cause of preterm delivery.

Chorioamnionitis↗
PubMed2002

S-relaxin as a predictor of preterm delivery in women with symptoms of preterm labour.

OBJECTIVE: To evaluate whether serum relaxin (S-relaxin) can predict spontaneous delivery before 34 weeks of gestation in high risk pregnancies. DESIGN: A prospective cohort study. SETTING: Calculated sample size was reached over a two-year period, during which 9507 women gave birth. Of these, 157 healthy women were eligible for the study as they were admitted with symptoms of delivery before 34 weeks of gestation. Ninety-three women were included. Overall participation rate was 59%. POPULATION: Healthy women with singleton pregnancies with symptoms of delivery before 34 weeks of gestation. METHODS: S-relaxin was measured using a standard sandwich ELISA. MAIN OUTCOME MEASURES: End points were preterm delivery before 34 weeks of gestation and delivery within three days from initiation of symptoms. The best possible prediction of preterm delivery was established using logistic regression for risk factors individually associated with preterm delivery before 34 weeks of gestation. S-relaxin was dichotomised to obtain best possible fit and then entered into the model. The same analyses were done for delivery within three days. RESULTS: Median S-relaxin levels varied significantly in the women with preterm prelabour rupture of membranes (PPROM) (316 pg/mL), contractions (222 pg/mL) or ripe cervices (203 pg/mL) (P < 0.05). S-relaxin above the 80th centile (> or = 300 pg/mL) was associated with an increased risk of preterm delivery [crude OR = 4.8; (95% CI: 1.9-12)]. Likelihood ratio of a positive test is 2.6 (1.5-4.9) and S-relaxin resulted in a post-test probability of preterm delivery of 0.72, compared with a pre-test probability of 0.49. S-relaxin contributed to the identification of delivery within three days [adj. OR = 11 (95% CI: 1.8-64)]. CONCLUSION: S-relaxin may be a useful predictor in women with symptoms of delivery before 34 weeks of gestation.

Body Mass Index↗
PubMed2000

[A case-control study on the risk factors for preterm delivery].

The risk factors for preterm delivery were analyzed with 1:2 matched case-control study by conditional logistic regression analysis. The result showed that the main risk factors for preterm delivery were neuroticism scores, premature rupture of the membranes, husband's smoking frequency during the third trimester of pregnancy, pregnancy induced hypertension, working strength and first-trimester vaginal bleeding. It is indicated that an examination before delivery and gaining weight during pregnancy are helpful to decrease the occurrence of preterm delivery.

Adult↗
PubMed2005

The heritability of preterm delivery.

OBJECTIVE: To study the heritability of preterm delivery. METHODS: Women who delivered a singleton infant at less than 36 weeks of gestation were asked about their family history. Twenty-eight families were identified in which the proband had at least five first- or second-degree relatives with preterm delivery. An extensive genealogy database (GenDB) was constructed using more than 9,000 genealogy sources in the public domain (records before 1929). GenDB documents the relationships between more than 17.5 million ancestors and 3.5 million descendants of approximately 10,000 individuals who moved to Utah in the mid 1800s. This database was searched for the names, birth dates, and birthplaces of the four grandparents for each of the 28 probands. Pairwise coefficients of kinship were determined for the 93 preterm delivery grandparents identified, and for sets of 100 individuals born in the 1920s who were randomly selected from the population database. RESULTS: Probands had a mean of 3.3 grandparents included in this database. The average coefficient of kinship for controls was 1.5 x 10(6) (standard deviation = 0.6 x 10(6)). This measure agrees with previous calculations for the Utah population. The coefficient of kinship for familial preterm delivery grandparents was more than 50 standard deviations higher (3.4 x 10(5) [P < .001]). CONCLUSION: This study confirms the familial nature of preterm delivery. On average, gravidae randomly selected from our population are 23rd degree relatives, while these preterm delivery probands are eighth-degree relatives. A genome-wide scan using these affected families is underway.

Adolescent↗
PubMed1990

Prediction of risk for preterm delivery by ultrasonographic measurement of cervical length.

Risk assessment for preterm delivery remains difficult, particularly among women with no prior history of preterm birth. We hypothesized that accurate assessment of cervical length by endovaginal ultrasonography could predict preterm delivery risk. A total of 178 patients with singleton gestations and without cervical incompetence were studied with transabdominal ultrasonography and endovaginal ultrasonographic cervical length measurement and manual vaginal examination of cervical length. A total of 113 patients who were evaluated by 30 weeks' gestation (excluding four induced preterm deliveries) were analyzed. Preterm delivery risk was compared between women with cervical lengths equal to or greater than the median and those with cervical lengths less than the median. An endovaginal ultrasonographic cervical measurement less than 39 mm was associated with a significantly increased risk of preterm delivery (25.0% versus 6.7%) and detected 76% of preterm births. Manual examination of cervical effacement detected 71% of preterm births, but transabdominal ultrasonographic measurement of cervical length was not preditive. Endovaginal ultrasonographic cervical measurement predicted increased preterm delivery risk regardless of parity or obstetric history. Endovaginal ultrasonography is a promising method for the prediction of risk of preterm birth. Because it has the potential to be an objective measure of cervical length, endovaginal ultrasonography may be superior to manual digital examination for preterm delivery risk assessment.

Cervix Uteri↗
PubMed1999

Racial differences in the patterns of singleton preterm delivery in the 1988 National Maternal and Infant Health Survey.

OBJECTIVES: To determine if the association between race and preterm delivery would persist when preterm delivery was partitioned into two etiologic pathways. METHODS: We evaluated perinatal and obstetrical data from the 1988 National Maternal and Infant Health Survey and classified preterm delivery as spontaneous or medically indicated. Discrete proportional hazard models were fit to assess the risk of preterm delivery for Black women compared with White women adjusting for potential demographic and behavioral confounding variables. RESULTS: Preterm delivery occurred among 17.4% of Black births and 6.7% of White births with a Black versus White unadjusted hazard ratio (HR) of 2.8 (95% CI = 2.4-3.3). The adjusted HR for a medically indicated preterm delivery showed no racial difference in risk (HR = 1.0, 95% CI = 0.4-2.6). However, for spontaneous preterm delivery between 20 and 28 weeks gestation, the Black versus White adjusted hazard ratio (HR) was 4.9 (95% CI = 3.4-7.1). CONCLUSIONS: Although we found an increased unadjusted HR for preterm delivery among Black women compared with White women, the nearly fivefold increase in adjusted HR for the extremely preterm births and the absence of a difference for medically indicated preterm delivery was unexpected. Given the differences in the risks of preterm birth between Black and White women, we recommend to continue examining risk factors for preterm delivery after separating spontaneous from medically indicated preterm birth and subdividing preterm delivery by gestational age to shed light on the reasons for the racial disparity.

Adolescent↗