The Preterm Prediction Study: association between cervical interleukin 6 concentration and spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

OBJECTIVE: The aim of this study was to determine the interrelationship between cervical concentration of interleukin 6 and detection of fetal fibronectin and other risk factors for spontaneous preterm birth.Study Design: All patients with spontaneous preterm birth at <35 weeks' gestation (case patients; n = 125) and subjects matched for race, parity, and center delivered at > or = 37 weeks' gestation (n = 125; control subjects) were selected from women enrolled in the National Institute of Child Health and Human Development's Preterm Prediction Study. Interleukin 6 concentrations were determined by enzyme-linked immunosorbent assay in cervical swabs obtained at 22 weeks' to 24 weeks 6 days' gestation. Cutoffs to define an elevated interleukin 6 concentration included the 90th and 95th percentiles for control subjects (>305 and >538 pg/mL, respectively). RESULTS: The mean (+/-SD) interleukin 6 concentration was significantly higher in case patients than in control subjects (212 +/- 339 vs 111 +/- 186 pg/mL; P = .008). With either cutoff value elevated interleukin 6 concentration was significantly associated with spontaneous preterm birth (90th percentile, 20% vs 9.6%; P = .02; 95th percentile, 12% vs 4.8%; P = .04). Cervical interleukin 6 levels were highest within 4 weeks of delivery, and the trend continued until term. Elevated interleukin 6 concentration was not significantly associated with bacterial vaginosis, maternal body mass index <19.8 kg/m2, or a short cervix (< or = 25 mm), but it was significantly associated with a positive cervicovaginal fetal fibronectin test result (90th percentile, odds ratio, 5.5; 95% confidence interval, 2.6-11.9; 95th percentile, odds ratio, 5.3, 95% confidence interval, 2.1-12.9). The mean interleukin 6 concentration among women with a positive fibronectin test result was 373 +/- 406 pg/mL; that among women with a negative fetal fibronectin test result was 130 +/- 239 pg/mL (P = .001). In a regression analysis that adjusted for risk factors significantly associated with spontaneous preterm birth in this population (positive fetal fibronectin test result, body mass index <19.8 kg/m2, vaginal bleeding in the first or second trimester, previous spontaneous preterm birth, and short cervix) elevated cervical interleukin 6 concentration was not independently associated with spontaneous preterm birth (odds ratio, 1.8; 95% confidence interval, 0.8-4.3). CONCLUSIONS: At 24 weeks' gestation cervical interleukin 6 concentration in women who subsequently had a spontaneous preterm birth at <35 weeks' gestation was significantly elevated relative to those who were delivered at term. The association was particularly strong within 4 weeks of testing. A positive fetal fibronectin test result was strongly associated with elevated cervical interleukin 6 concentration, but bacterial vaginosis was not.     

The Preterm Prediction Study: association of second-trimester genitourinary chlamydia infection with subsequent spontaneous preterm birth

OBJECTIVE: This study was undertaken to determine the association between genitourinary tract infection with Chlamydia trachomatis and spontaneous preterm birth. STUDY DESIGN: Genitourinary tract infection with C trachomatis was determined with a ligase chain reaction assay of voided urine samples collected at 24 weeks' gestation (22 weeks' to 24 weeks 6 days' gestation) and 28 weeks' gestation (27 weeks' to 28 weeks 6 days' gestation). Case patients (spontaneous preterm birth at <37 weeks' gestation; n = 190) and control subjects (delivery at >/=37 weeks' gestation, matched for race, parity, and center; n = 190) were selected from 2929 women enrolled in the Preterm Prediction Study of the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. RESULTS: Genitourinary C trachomatis infection (11% overall) was significantly more common among the case patients than among the control subjects at 24 weeks' gestation (15.8% vs 6.3%; P =.003) but not at 28 weeks' gestation (12.6% vs 10.9%; P =.61). Women with chlamydia infection were more likely to have bacterial vaginosis (57.1% vs 32.9%; P =.002) and a short cervical length (相似文献   

Risk of preterm delivery in relation to maternal low birth weight

OBJECTIVE: We examined the relationship between maternal low birth weight and preterm delivery risk. METHODS: Information concerning maternal birth weight was collected during in-person interviews. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). Preterm delivery cases were studied in aggregate, 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 early preterm delivery [gestational age at delivery<34 weeks]). RESULTS: After adjusting for confounders, women weighing<2,500 g at birth had a 1.54-fold increased risk of preterm delivery versus women weighing=2,500 g (95% CI 0.97-2.44). Maternal low birth weight was associated with a 2-fold increased risk of spontaneous preterm delivery (95% CI 1.03-3.89), but weakly associated with preterm premature rupture of membranes (OR=1.44; 95% CI 0.67-3.09) and medically induced preterm delivery (OR=1.10; 95% CI 0.43-2.82). Maternal low birth weight was more strongly associated with early preterm delivery (OR=1.94) than with moderate preterm delivery (OR=1.46). Women weighing<2,500 g at birth and who became obese (pre-pregnancy body mass index, =30 kg/m2) before pregnancy had a 3.65-fold increased risk of preterm delivery (95% CI 1.33-10.02) versus women weighing=2,500 g at birth and who were not obese prior to pregnancy (<30 kg/m2). CONCLUSIONS: Results confirm earlier findings linking maternal low birth weight with future risk of preterm delivery.     

Single nucleotide polymorphisms in the human progesterone receptor gene and spontaneous preterm birth

Progesterone supplementation can prevent preterm birth in some high-risk women. Progesterone binds to progesterone receptor (PR) and modulates the expression of target genes. This study investigates the association between single nucleotide polymorphisms (SNPs) in the PR gene and spontaneous preterm birth. DNA was extracted from consecutive patients with preterm birth (n = 78) and term controls (n = 415), and genotyping was performed for 3 PR SNPs (+331[G>A], + 770[C>T], +660[G>T]) using Sequenom matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed by chi(2) test and logistic regression analysis. Multivariate analysis showed no association between maternal carriage of minor + 331T, +770T, and/or +660T alleles and preterm birth when controlled for maternal age, ethnicity, gravidity, parity, prior preterm birth, route of delivery, or neonatal outcome. Carriage of +770T and +660T (but not +331T) was associated with preterm birth in women with a body mass index <18.5 kg/m(2) (relative risk, 10.8; 95% confidence interval, 1.4-82.6; P = .02). Maternal carriage of minor alleles of +331(G>A), +770(C>T), and +660(G> T) SNPs in the PR gene is not associated with spontaneous preterm birth.     

Second-trimester cervical ultrasound: associations with increased risk for recurrent early spontaneous delivery

OBJECTIVE: To determine whether short cervical length or internal os funneling before 20 weeks' gestation predicts early preterm birth or pregnancy loss in women with at least one prior spontaneous early preterm birth. METHODS: Transvaginal cervical ultrasound examinations were done every 2 weeks on 69 women with singleton gestations and histories of at least one prior spontaneous birth between 16 and 30 weeks' gestation. The results of those examinations were correlated with gestational age at delivery. RESULTS: Among 53 women who had ultrasound examinations before 20 weeks' gestation, those with cervical lengths at or below the tenth percentile for the study population (22 mm, n = 4) or funneling of the internal os (n = 5) were more likely than women without those factors to have spontaneous preterm births within 2 weeks (33% versus 0%, P = .01) or 4 weeks from the ultrasound examination (67% versus 0%, P < .001) or before 35 weeks' gestation (100% versus 19%, P < .001). Short cervical length or funneling between 20-24 and 25-29 weeks was also associated with increased risk of spontaneous preterm birth before 35 weeks' gestation (P < or = .05 and P = .002, respectively) but not with increased risk of spontaneous preterm birth within 2 or 4 weeks of ultrasound examination. CONCLUSION: Women with prior early spontaneous preterm births who have short cervical lengths or funneling of the internal cervical os before 20 weeks' gestation are at increased risk of subsequent spontaneous preterm birth.     

Low pre-pregnancy body mass index and risk of medically indicated versus spontaneous preterm singleton birth

Objective(s)

There were three primary objectives of this study: (1) to estimate the risk of preterm and very preterm birth by severity of low pre-pregnancy body mass index (BMI), (2) to determine if the risk in preterm and very preterm birth by severity of low pre-pregnancy BMI differs for spontaneous versus medically indicated preterm delivery, and finally (3) to determine if there is a difference in the risk for preterm and very preterm birth by severity of low pre-pregnancy BMI across gradations of gestational weight gain.

Study design

This study utilized the Missouri maternally linked cohort files from 1989 to 1997. After restricting analyses to singleton live births (gestational age 20–44 weeks) and women with either a low or normal BMI, the final study population consisted of 437,403 births. Pre-pregnancy BMI was categorized as normal (19.5–24.9), mild thinness (17.0–18.5), moderate thinness (16.0–16.9) and severe thinness (≤15.9). Statistical analyses included chi-square tests and logistic regression with generalized estimating equations (GEE).

Results

Underweight mothers were more likely to experience a preterm delivery. For all preterm births, the risk among underweight mothers increased with ascending underweight severity (p < 0.01). Higher risk estimates were observed for spontaneous than for medically indicated preterm birth. For each BMI category, extreme risk values for spontaneous preterm births were observed among women with very low gestational weight gain (<0.12 kg/week). Severely thin mothers with very low and very high pregnancy weight gain were at the greatest risk for spontaneous preterm birth. By contrast, underweight women with moderate gestational weight gain (0.23–0.68 kg/week) had the lowest risk for spontaneous preterm birth with the sole exception of moderately underweight gravidas.

Conclusions

These findings suggest that women with low or normal pre-pregnancy BMI should be counseled to maintain a moderate level of gestational weight gain (0.23–0.68 kg/week) in order to reduce their risk for preterm birth. Further, our observation that severity of low pre-pregnancy BMI was associated directly (in a dose–response pattern) with preterm birth highlights the importance of preconceptional counseling for women—specifically the importance of women achieving or maintaining a normal weight status prior to pregnancy.     

Number and gestational age of prior preterm births does not modify the predictive value of a short cervix

OBJECTIVE: This study was undertaken to determine whether the number and gestational age of prior preterm deliveries modifies the significance of endovaginal sonographic cervical length less than 25 mm for the prediction of recurrent preterm birth less than 35 weeks' gestation. STUDY DESIGN: Secondary analysis of a multicenter, blinded, observational study. Endovaginal ultrasonographic examinations were scheduled at 2-week intervals between 16 and 23 weeks' gestation in singleton pregnancies of 181 gravid women with at least 1 prior spontaneous preterm birth between 16 and 32 weeks' gestation. RESULTS: The earliest prior preterm birth occurred before 23 weeks in 61 women and at 23.0 to 31 weeks in 115; 5 had missing gestational age data. Cervical length was not different between these 2 groups both at the initial scan (median 38 vs 37 mm, P=.54) and considering the shortest ever observed cervical length over the entire study period (median 30 vs 30 mm, P=.97). Cervical length less than 25 mm was associated with spontaneous preterm birth less than 35 weeks for both groups (positive predictive value 80% vs 71%, P>.99). There were 134 women with 1 prior preterm delivery (74%) and 47 with 2 or more. Cervical lengths were not different between these 2 groups at the initial scan (median 36.5 vs 37 mm, P=.52) or over the entire study period (median 30 vs 32 mm, P=.31). The positive predictive value of cervical length less than 25 mm for subsequent spontaneous premature birth was not significantly higher in gravid women with multiple prior preterm births (100% vs 73%, P>.99). CONCLUSION: Neither the number nor the gestational age of prior preterm births modify the predictive value of a cervical length less than 25 mm at 16 to 19 weeks for recurrent spontaneous preterm birth.     

Estimated effect of 17 alpha-hydroxyprogesterone caproate on preterm birth in the United States

OBJECTIVE: A multicenter, randomized placebo-controlled trial among women with singleton pregnancies and a history of spontaneous preterm birth found that weekly injections of 17 alpha-hydroxyprogesterone caproate (17P), initiated between 16 and 20 weeks of gestation, reduced preterm birth by 33%. The current study estimated both preterm birth recurrence and the potential reduction in the national preterm birth rate. METHODS: Using 2002 national birth certificate data, augmented by vital statistics from 2 states, we estimated the number of singleton births delivered to women eligible for 17P through both a history of spontaneous preterm birth and prenatal care onset within the first 4 months of pregnancy. The number and rate of recurrent spontaneous preterm births were estimated. To predict effect, the reported 33% reduction in spontaneous preterm birth attributed to 17P therapy was applied to these estimates. RESULTS: In 2002, approximately 30,000 recurrent preterm births occurred to women eligible for 17P, having had a recurrent preterm birth rate of 22.5%. If 17P therapy were delivered to these women, nearly 10,000 spontaneous preterm births would have been prevented, thereby reducing the overall United States preterm birth rate by approximately 2%, from 12.1% to 11.8% (P < .001), with higher reductions in targeted groups of eligible pregnant women. CONCLUSION: Use of 17P could reduce preterm birth among eligible women, but would likely have a modest effect on the national preterm birth rate. Additional research is urgently needed to identify other populations who might benefit from 17P, evaluate new methods for early detection of women at risk, and develop additional prevention strategies. LEVEL OF EVIDENCE: III.     

Weight gain and spontaneous preterm birth: the role of race or ethnicity and previous preterm birth

OBJECTIVE: To study how the relationship between gestational weight gain and spontaneous preterm birth interacts with maternal race or ethnicity and previous preterm birth status. METHODS: This was a retrospective cohort study of singleton births to women of normal or low prepregnancy body mass index. Gestational weight gain was measured as total weight gain divided by weeks of gestation at delivery, and weight gain was categorized as low (less than 0.27 kg/wk,), normal (0.27-0.52 kg/wk), or high (more than 0.52 kg/wk). Univariable and multivariable analyses were performed on the relationship between weight gain categories and spontaneous preterm birth, stratified by maternal race or ethnicity and history of previous preterm birth. RESULTS: Overall, low weight gain was associated with spontaneous preterm birth (adjusted odds ratio [AOR] 2.5, 95% confidence interval [CI] 2.0-3.1). Although low gain was consistently associated with increased spontaneous preterm birth, some differences were found in subgroup analysis. Among African Americans with a previous preterm birth, both low and high weight gain were associated with increased odds of spontaneous preterm birth (AOR for low weight gain 4.3, 95% CI 1.2-15.5; AOR for high weight gain 6.1, 95% CI 1.8-20.2). For all other groups, high weight gain was not associated with spontaneous preterm birth. Among Asians with a previous preterm birth, low weight gain was not statistically significantly associated with spontaneous preterm birth (AOR 1.9, 95% CI 0.5-7.7). Among Asians there was also a non-statistically significant inverse relationship between high weight gain and spontaneous preterm birth (AOR 0.5, 95% CI 0.3-1.1). CONCLUSION: These results confirm an association between low maternal weight gain and spontaneous preterm birth. The effect modification of maternal race or ethnicity and history of previous preterm birth on this association deserves further study. LEVEL OF EVIDENCE: II-2.     

Spontaneous and indicated preterm delivery in pregestational diabetes mellitus: etiology and risk factors

OBJECTIVE: To characterize the indications for preterm delivery and identify risk factors predicting preterm delivery in pregnancies complicated by pregestational diabetes (PGDM). STUDY DESIGN: A retrospective cohort study of all women with type 1 or type 2 diabetes mellitus followed from preconception to delivery at our institute from 1996 to 2004 (study group). Rates of spontaneous and indicated preterm delivery were compared with a control group of nondiabetic women. RESULTS: Rates of preterm delivery were 26.6% (119/448) and 6.0% (1,038/17,370) in the study and control groups, respectively (P < 0.001). The PGDM group had higher rates of both spontaneous (6.9% vs. 4.8%, P < 0.001) and indicated (19.6% vs. 1.2%, P < 0.001) preterm deliveries. Most of the preterm deliveries in the PGDM group were indicated (73.9%) compared with 20.1% in the control group (P < 0.001). Preeclampsia was the most significant factor associated with indicated preterm delivery in the PGDM group (OR = 11.7, 95% CI = 3.3-41.7), followed by nephropathy, nulliparity, HbA1c levels prior to conception and prior to delivery, duration of diabetes, prepregnancy body mass index and weight gain during pregnancy. Spontaneous preterm delivery was related to duration of diabetes, presence of nephropathy, and previous preterm delivery. CONCLUSION: The risk of both spontaneous and indicated preterm delivery is increased in pregnancies complicated by PGDM. Except for glycemic control, none of the risk factors identified is modifiable by preconception or antenatal care.     

Transvaginal ultrasonography in the prediction of preterm birth after treatment for cervical intraepithelial neoplasia

OBJECTIVE: To estimate whether cervical length measured by transvaginal ultrasonography in women having had loop electrosurgical excision procedure (LEEP), cold knife conization, or cryotherapy predicts spontaneous preterm birth. METHODS: Women with a history of LEEP, cold knife conization, or cryotherapy and who were subsequently pregnant with singleton gestations were prospectively compared with both a low-risk control group and women with previous spontaneous preterm birth. A transvaginal ultrasonogram measuring cervical length was performed at 24 to 30 weeks of gestation. Primary outcomes included cervical length and spontaneous preterm birth less than 37 weeks. Secondary outcomes were spontaneous preterm birth less than 34 weeks, low birth weight, and maternal and neonatal outcomes. RESULTS: Women with previous LEEP (N = 75), cold knife conization (N = 21), and cryotherapy (N = 36) had shorter cervical lengths (3.54, 3.69, and 3.75 cm respectively) than the low-risk control group (N = 81, 4.21 cm) (P < .001, P = .03, P = .02 respectively) and similar lengths to women with a previous spontaneous preterm birth (N = 63, 3.78 cm). Loop electrosurgical excision procedure and cold knife conization, but not cryotherapy, were associated with spontaneous preterm birth less than 37 weeks (odds ratio 3.45, 95% confidence interval 1.28-10.00, P = .02; and odds ratio 2.63, 95% confidence interval 1.28-5.56, P = .009, respectively). Using a cutoff of 3.0 cm, transvaginal ultrasonography had a positive predictive value of 53.8% and negative predictive value of 95.2% for spontaneous preterm birth less than 37 weeks in women with LEEP. CONCLUSION: Women with a history of LEEP, cold knife conization, and cryotherapy all independently have shorter cervical lengths than low-risk controls and similar lengths to women with previous spontaneous preterm birth. Loop electrosurgical excision procedure and cold knife conization are associated with spontaneous preterm birth less than 37 weeks, and transvaginal ultrasonography predicts preterm birth in women who have had LEEP. LEVEL OF EVIDENCE: II-2.     

The preterm prediction study: maternal serum relaxin, sonographic cervical length, and spontaneous preterm birth in twins

OBJECTIVE: The risk of spontaneous preterm birth has been related to decreased cervical length and to increased serum relaxin. To explore a relationship between these findings, we used data collected from two prior studies to correlate relaxin levels with cervical length and risk of spontaneous preterm birth in women with twin pregnancies. METHODS: In a secondary analysis of data collected in two previous observational studies of risk factors for preterm birth, relaxin levels in maternal serum and cervical length were measured at 24 (n= 188) and 28 (n= 145) weeks in women with spontaneous twin pregnancies. Relaxin, as a continuous variable, was related by logistic regression analysis to risk of spontaneous preterm birth before 37, 35, and 32 weeks' gestation, and by Spearman correlation coefficients to cervical length at 24 and 28 weeks. Cervical length at 24 weeks was known to be correlated with spontaneous preterm birth before 37, 35, and 32 weeks (P =.03,.01, and.002, respectively) in this study population. RESULTS: Cervical length did not correlate with relaxin levels at 24 (P=.601) or 28 (P=.304) weeks. Relationships between relaxin and spontaneous preterm birth were observed at 24 weeks for births before 37 weeks (odds ratio [OR] 1.56, 95% confidence interval [CI] 1.00, 2.44; P=.05), and at 28 weeks for births before 35 weeks (OR 1.97, 95% CI 1.05, 3.70; P=.034) and 32 weeks (OR 2.43, 95% CI 1.01, 5.83; P=.048). CONCLUSION: The absence of an association between relaxin and cervical length suggests that increased relaxin does not explain the inverse correlation between cervical length and spontaneous preterm birth in women with spontaneous twin pregnancies.     

Primiparity: An ‘intermediate’ risk group for spontaneous and medically indicated preterm birth

Objective.?Most women in their first pregnancy are at ‘unknown’ risk for preterm birth. We hypothesized that such women may be at an increased risk for preterm birth in comparison to those with a prior term birth.

Methods.?We used Missouri's maternally-linked data (1989–97), comprised of women delivering their first singleton live birth (N = 259 431) and women delivering their first two consecutive singleton live births (N = 154 810). We compared preterm birth (<37 weeks) rates among women with a previous term birth, women with no reproductive history (primiparous women), and in those with a previous preterm birth. Risks of spontaneous and medically indicated preterm birth were also examined after adjustments for confounders through multivariate log-binomial regression models.

Results.?Preterm birth rates were 8.1%, 9.6%, and 23.3% among women with a previous term birth, among primiparous women, and among those with a previous preterm birth, respectively. In comparison to women with a prior term birth, risks of spontaneous preterm birth among primiparous women and among women with a prior preterm birth were 1.1-fold (95% confidence interval (CI) 1.0, 1.2) and 2.5-fold (95% CI 2.4, 2.6) higher, respectively. These risks were higher for medically indicated preterm birth among both primiparous women (RR 1.3, 95% CI 1.2, 1.4) and those with a prior preterm birth (RR 3.2, 95% CI 3.0, 3.5) than for spontaneous preterm births.

Conclusions.?Primiparous women are at increased risk of both medically indicated and spontaneous preterm birth. The findings suggest that studies on preterm birth should consider a risk assignment to include three groups: low-risk (prior term birth), intermediate risk (primiparity), and high-risk (prior preterm birth). This strategy will be informative for the identification of women with impending risk of delivering preterm, and complications associated with prematurity.     

Primiparity: an 'intermediate' risk group for spontaneous and medically indicated preterm birth.

OBJECTIVE: Most women in their first pregnancy are at 'unknown' risk for preterm birth. We hypothesized that such women may be at an increased risk for preterm birth in comparison to those with a prior term birth. METHODS: We used Missouri's maternally-linked data (1989-97), comprised of women delivering their first singleton live birth (N = 259 431) and women delivering their first two consecutive singleton live births (N = 154 810). We compared preterm birth (<37 weeks) rates among women with a previous term birth, women with no reproductive history (primiparous women), and in those with a previous preterm birth. Risks of spontaneous and medically indicated preterm birth were also examined after adjustments for confounders through multivariate log-binomial regression models. RESULTS: Preterm birth rates were 8.1%, 9.6%, and 23.3% among women with a previous term birth, among primiparous women, and among those with a previous preterm birth, respectively. In comparison to women with a prior term birth, risks of spontaneous preterm birth among primiparous women and among women with a prior preterm birth were 1.1-fold (95% confidence interval (CI) 1.0, 1.2) and 2.5-fold (95% CI 2.4, 2.6) higher, respectively. These risks were higher for medically indicated preterm birth among both primiparous women (RR 1.3, 95% CI 1.2, 1.4) and those with a prior preterm birth (RR 3.2, 95% CI 3.0, 3.5) than for spontaneous preterm births. CONCLUSIONS: Primiparous women are at increased risk of both medically indicated and spontaneous preterm birth. The findings suggest that studies on preterm birth should consider a risk assignment to include three groups: low-risk (prior term birth), intermediate risk (primiparity), and high-risk (prior preterm birth). This strategy will be informative for the identification of women with impending risk of delivering preterm, and complications associated with prematurity.     

The preterm prediction study: granulocyte colony-stimulating factor and spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network

OBJECTIVE: Granulocyte colony-stimulating factor is elevated in the amniotic fluid and plasma of women with chorioamnionitis and active preterm labor. We investigated the relationship between plasma granulocyte colony-stimulating factor and subsequent spontaneous preterm birth in pregnant women without symptoms. STUDY DESIGN: We performed a nested case-control study involving 194 women who had a singleton spontaneous preterm birth and 194 matched term control subjects from the patient pool (n = 2929) enrolled in the Preterm Prediction Study. Plasma collected at 24 and 28 weeks' gestation was analyzed for granulocyte colony-stimulating factor, and the results were compared with subsequent spontaneous preterm birth. RESULTS: Compared with term control subjects, women who were delivered of their infants spontaneously at <28 weeks' gestation had increased mean granulocyte colony-stimulating factor values at 24 weeks' gestation (84.7 +/- 38.4 vs 67.7 +/- 28.6 pg/mL; P =.049), and women who were delivered of their infants at <32 weeks' gestation had increased mean plasma granulocyte colony-stimulating factor values at 28 weeks' gestation (80.4 +/- 24.1 vs 55.9 +/- 16.5 pg/mL; P =. 001). At 24 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile in control subjects (approximately 80 pg/mL) was found in 48.9% (23/47) of all women delivered of their infants at <32 weeks' gestation versus 14.9% (7/47) of the term control subjects (adjusted odds ratio, 6.2; 95% confidence interval, 1.8-20. 8). At 28 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile was found in 36.8% (7/19) of women delivered of their infants at <32 weeks' gestation versus 5.3% (1/19) of term control subjects (adjusted odds ratio, 25.7; 95% confidence interval, 1.5-470.4). When measured at 24 or 28 weeks' gestation, granulocyte colony-stimulating factor did not predict spontaneous preterm birth at 32 to 34 weeks' gestation or at 35 to 36 weeks' gestation. CONCLUSION: In pregnant women without symptoms at 24 and 28 weeks' gestation, elevated plasma granulocyte colony-stimulating factor levels are associated with subsequent early (<32 weeks' gestation) spontaneous preterm birth, especially within the next 4 weeks, but not with late spontaneous preterm birth. These data provide further evidence that early spontaneous preterm birth is associated with an inflammatory process that is identifiable by the presence of a cytokine in maternal plasma several weeks before the early spontaneous preterm birth; however, later spontaneous preterm birth is not associated with this process.     

Nulliparity and preterm birth in the era of obesity epidemic

Objective.?To assess the impact of obesity on preterm birth among nulliparous women.

Methods.?Retrospective cohort study of nulliparous mothers delivering infants in Florida between 2004 and 2007. Women were classified as non-obese (pre-pregnancy body mass index (BMI) <30) or obese (BMI?≥?30). The main outcomes assessed were preterm birth, very preterm birth and extremely preterm birth. Risk estimates were obtained using logistic regression. Multiparous non-obese mothers were the referent group for all analyses.

Results.?As compared to multiparous women, nulliparous mothers had an increased risk of very preterm and extremely preterm birth with the highest risk observed for extremely preterm birth (odds ratios (OR)?=?1.37, 95% CI?=?1.28, 1.47) (p for trend <0.01). Obese nulliparous mothers had an elevated risk of preterm, very preterm and extremely preterm birth, with the risk of extremely preterm birth being the most pronounced (OR?=?1.97, 95% CI?=?1.75–2.22) [p for trend <0.05]. The heightened risk associated with obesity among nulliparous women was observed across all racial/ethnic sub-populations, with black nulliparous obese mothers being at greatest risk of all preterm birth-subtypes.

Conclusions.?Obesity is a risk marker for preterm, very preterm and extremely preterm birth among first-time mothers and particularly among blacks and Hispanics.     

The influence of obesity and diabetes on the prevalence of macrosomia

OBJECTIVE: This study was undertaken to determine the relative contribution of abnormal pregravid maternal body habitus and diabetes on the prevalence of large-for-gestational-age infants. STUDY DESIGN: Maternal and neonatal records for singleton term (> or =37 weeks' estimated gestational age) deliveries January 1997 through June 2001 were reviewed. Subjects were characterized by pregravid body mass index (BMI), divided into underweight (BMI <19.8 kg/m2), normal (BMI 19.8-25 kg/m2), overweight (BMI 25.1-30 kg/m2), and obese (BMI >30 kg/m2) subgroups. Diabetes was classified as gestational, treated with diet alone (A1GDM), or with insulin (A2GDM), and pregestaional diabetes (PDM). Newborn weight greater than the 90th percentile for gestational age, based on published local birth weight data, defined large for gestational age (LGA). The risk of LGA delivery for underweight, overweight, and obese women were compared with that of women with normal pregravid BMI. Multiple regression models, including parity, newborn sex, BMI, race, and diabetes, were constructed to examine the relative effect of abnormal BMI and diabetes on the risk of the delivery of an LGA infant. RESULTS: Complete data for 12,950 deliveries were included (1,640 [13.0%] underweight, 2,991 [23.7%] overweight, and 2,928 [23.2%] obese). LGA delivery affected 11.8% of the study sample; 303 (2.3%) of subjects had A1GDM, whereas 94 (0.7%) had A2GDM, and 133 (1.6%) had PDM. Compared with normal BMI subjects, obese women were at elevated risk for LGA delivery (16.8% vs 10.5%; P < .0001) as were overweight women (12.3% vs 10.5%; P = .01). Diabetes was also a risk factor for LGA delivery (A1GDM: [29.4% vs 11.4%]; A2GDM: [29.8% vs 11.7%]; PDM: [38.3% vs 11.6%]; P < .0001 for each). Other risk factors for LGA delivery included parity (13.2% vs 9.5%; P < .0001), and male gender (14.3% vs 9.3%; P < .0001). Black race and low pregravid BMI were associated with a lower risk of LGA delivery (9.0% vs 13.7%; P < .0001) and (6.4% vs 10.5%; P = .006), respectively. Multiple regression revealed the independent influence of pregravid obesity and PDM, increasing the risk of LGA delivery (BMI >30kg/m 2 [Adjusted odds ratio (AOR) = 1.6]), and PDM (AOR = 4.4). CONCLUSION: Obesity and pregestational diabetes are independently associated an increased risk of LGA delivery. The impact of abnormal body habitus on birth weight grows as BMI increases. Diabetes has the greatest affect on the normal and underweight population. With the increasing prevalence and relative frequency of overweight and obese women in pregnancy compared with diabetes (46.7% vs 4.1%), abnormal maternal body habitus exhibits the strongest influence on the prevalence of LGA delivery in our population.     

Short interpregnancy interval and risk of spontaneous preterm delivery

OBJECTIVES: Short interpregnancy intervals are related to increased prevalence of adverse perinatal outcomes. However, the reported association with preterm birth might be due to confounding by factors such as previous pregnancy outcomes, socioeconomic level or lifestyles. The objective of this study was to evaluate the effect of short interpregnancy interval on the occurrence of spontaneous preterm delivery. STUDY DESIGN: The prevalence of a short interpregnancy interval, defined as six or less months between a preceding delivery or abortion and the last menstrual period before index pregnancy, was compared between 263 spontaneous preterm (<37 weeks) and 299 term (37-42 weeks) consecutive births. Separate analyses were performed for early (<34 weeks) and late (34-36 weeks) preterm deliveries. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) were calculated using unconditional logistic regression. RESULTS: There was a significant association between short interpregnancy interval and spontaneous early preterm delivery, both crude (OR=3.9; 95% CI: 1.91-8.10) and adjusted for maternal age, school education, previous birth outcomes, antenatal care, smoking habits, body mass index and gestational weight gain (adj(OR)=3.6; 95% CI: 1.41-8.98). No significant effect on spontaneous late preterm delivery was found (crude(OR)=0.8; 95% CI: 0.32-1.83). CONCLUSIONS: This study showed that short interpregnancy intervals significantly increased the risk of early spontaneous preterm birth but no such effect was evident for late preterm deliveries.     

Laparoscopic management of benign adnexal mass in obese women

STUDY OBJECTIVE: To compare complications and rate of conversion to laparotomy between normal-weight, preobese, and obese women who underwent laparoscopic management of benign adnexal mass. DESIGN: Retrospective chart review (Canadian Task Force classification II-3). SETTING: Tertiary care teaching hospital. PATIENTS: One hundred seventy women who underwent laparoscopic surgery because of benign adnexal mass were placed in three groups on the basis of their body mass index (BMI) using the World Health Organization's classification (normal-weight [BMI 18.5-24.9 kg/m2], preobese [BMI 25-29.9 kg/m2], and obese [BMI > or = 30 kg/m2]). INTERVENTION: Retrospective comparison of conversions from laparoscopy to laparotomy, operative time, estimated blood loss, complications, history of pelvic inflammatory disease, endometriosis, and length of hospital stay was carried out among the different groups. MEASUREMENTS AND MAIN RESULTS: Overall, 170 laparoscopic cases were evaluated (64 with normal-weight, 67 preobese, and 39 obese women). The rate of conversion to laparotomy was significantly higher in the obese and preobese groups compared with the normal-weight women (17.9%, 17.9% vs 1.5%, p < .01). Obese women were 13 times more likely to undergo conversion than normal-weight women (OR 13.78; 95% CI 1.76-29.1). In addition, obese women had significantly longer surgeries (143 +/- 87 minutes vs 114 +/- 41 minutes [p = .04]) and longer hospital stay (1.07 +/- 1.83 days vs 0.51 +/- 1.06 days [p = .04]) when compared with normal-weight women. There was no significant difference in history of pelvic inflammatory disease, endometriosis, and adhesions at the time of laparoscopy between obese, preobese, and normal-weight women. The rate of complications was similar among the groups. CONCLUSION: Obese and preobese women undergoing laparoscopic management of benign adnexal mass were found to be at an increased risk for conversion to laparotomy, longer surgery and longer hospital stay. Obese and preobese women should be counseled extensively on morbidity associated with laparoscopy.     

睡眠呼吸障碍与自发性早产的巢式病例对照研究

目的:探讨妊娠晚期睡眠呼吸障碍是否为自发性早产的危险因素。方法:采用巢式病例对照研究,纳入从2018年10月-2019年5月在北京市大兴区人民医院住院妊娠晚期孕妇为研究对象。收集孕妇的相关资料,包括人口学信息、病史信息以及柏林问卷(Berlin Questionnaire,BQ)、匹兹堡睡眠质量指数(Pittsburgh Sleep Quality Index,PSQI)和艾普沃斯嗜睡量表(Epworth Sleepiness Scale,ESS)。依据我国早产临床诊断与治疗指南(2014)诊断为自发性早产者为自发性早产组(46例),无早产等合并症的足月产孕妇为足月产组(407例)。比较2组孕妇的一般情况、睡眠呼吸障碍问卷评分等相关因素,并分析可能影响自发性早产的独立危险因素。结果:自发性早产组孕妇的年龄、孕前BMI、既往流产次数及早产史均高于足月分娩组,受教育程度低于足月分娩组,差异均有统计学意义(均P<0.05)。自发性早产组PSQI总分和BQ阳性率高于足月分娩组,差异均有统计学意义(均P<0.05)。Logistic回归分析显示在校正可能影响自发性早产的混杂因素后,BQ阳性孕妇发生自发性早产的风险约是BQ阴性孕妇的2.61倍(OR=2.61,95%CI:1.21~5.64,P=0.015)。结论:妊娠晚期具有阻塞性睡眠呼吸暂停高风险的孕妇发生自发性早产的可能性较高。