Frequency Of Preterm Delivery Research Articles

Outcome of twin pregnancies after assisted reproductive techniques—a comparative study

Objective: To compare obstetrical and perinatal outcome of twin pregnancies after assisted reproductive techniques (ART) with that of twins conceived spontaneously. Study design: Hospital based retrospective study. Results: There were 132 twin deliveries of which 36 were conceived after ART. Patients of the ART group were mostly nulliparous and slightly older. There was no statistically significant difference in the frequency of preterm delivery or mean gestational age at delivery. Elective Caesarean delivery was more frequent in twin pregnancies conceived after ART, and there were no other differences in maternal complications. There was also no difference in the mean birth weight or frequency of neonatal complication between the two groups. Conclusion: In this comparative study, the obstetric and neonatal outcomes between spontaneous twins and those conceived after ART are similar except for higher operative deliveries in the latter group of twins.

Transvaginal ultrasonography in detection of cervical incompetence

Background: To examine the relationship between transvaginal ultrasound cervical changes and pregnancy outcome in women at risk of cervical incompetence and preterm delivery.Methods: In 100 pregnancies with clinical and ultrasonic signs of cervical incompetence, the length of the cervix, the thickness of the anterior wall of a lower uterine segment and the width of the endo‐cervical canal have been evaluated ultrasonically. These parameters were followed longitudinally from the 10 to 36 week gestation in the healthy pregnancies and pregnancies at risk for cervical incompetence and preterm delivery.Results: In patients from 10 to 14 weeks, the cervix is significantly longer than in the 25–36 week group and the anterior wall of the lower uterine segment in the 10–14 week group is significantly thicker than in the 20–36 week group. In pregnancies at risk for cervical incompetence, cervical lengths and wall thickness, were significantly different from those in comparable controls. Forty‐five percent of the patients in the at‐risk group, with cervical cerclage, delivered at 37.5 weeks and 8.5% of pregnancies ended in abortion when the amniotic membrane herniated into the cervical canal. The frequency of preterm delivery was 60, 38 and 15% for cervical length of <10, 10–20, and 20–30 mm.Conclusions: A shortened cervix with decreased thickness of the anterior wall of lower uterine segment and dilated endo‐cervical canal shows a strong association with cervical incompetence and preterm birth.

P151Transvaginal ultrasonography in detection of cervical incompetency

ObjectivesTo examine the relationship between transvaginal ultrasound cervical changes and pregnancy outcome in women at risk of cervical incompetency and preterm delivery.MethodIn 100 pregnancies with clinical and ultrasonic signs of cervical incompetency, the length of the cervix, the thickness of the anterior wall of a lower uterine segment and the width of the endocervical canal have been evaluated ultrasonically. These parameters were followed longitudinally from the 10th to 36th gestational week in the healthy pregnancies and pregnancies at risk of cervical incompetency and preterm delivery.ResultsIn patients from 10 weeks to 14 weeks the cervix is significantly longer than in the 25–36 week group and the anterior wall of the lower uterine segment in the 10–14 week group is significantly thicker than in the 20–36 week group. In pregnancies at risk of cervical incompetency, cervical lengths and wall thickness were significantly different from those in comparable controls. Forty‐five percent of the patients in the at‐risk group, with cervical cerclage, delivered at 37.5 weeks and 8.5% of pregnancies ended in abortion when the amnictic membrane herniated into the cervical canal. The frequencies of preterm delivery were 60%, 38% and 15% for cervical lengths of < 10 mm, 10–20 mm and 20–30 mm.ConclusionA shortened cervix with decreased thickness of the anterior wall of lower uterine segment and dilatated endocervical canal shows a strong association with cervical incompetency and preterm birth.

Risks of preeclampsia and adverse neonatal outcomes among women with pregestational diabetes mellitus

Objectives: This study was undertaken to determine the frequencies of preeclampsia and adverse neonatal outcomes among women with pregestational diabetes. Study Design: This was a prospective observation of pregnancy outcomes among 462 women with pregestational diabetes mellitus (White classes B-F) and singleton pregnancies who were enrolled in a multicenter trial to compare low-dose aspirin with placebo for preeclampsia prevention. The main outcome measures were preeclampsia and neonatal outcomes. Results: Among 462 women with pregestational diabetes, 92 (20%) had preeclampsia. Preeclampsia frequency rose significantly with increasing severity of diabetes according to White classification (class B, 11%; class C, 22%; class D, 21%; class R plus class F, 36%; P < .0001). Preeclampsia was also more common among women who had proteinuria at baseline (28% vs 18%; odds ratio, 1.75; 95% confidence interval, 1.02-3.01). Frequency of preterm delivery at <35 weeks’ gestation rose greatly with increasing severity of diabetes ( P = .0002). Women with proteinuria at baseline were significantly more likely to be delivered at <35 weeks’ gestation (29% vs 13%; odds ratio, 2.6; 95% confidence interval, 1.5-4.6) and to have small-for-gestational-age infants (14% vs 3%; odds ratio, 5.4; 95% confidence interval, 2.7-17.7), and they were less likely to have large-for-gestational-age infants (14% vs 40%; odds ratio, 0.2; 95% confidence interval, 0.1-0.5). Conclusion: Among women with pregestational diabetes mellitus, the frequency of preeclampsia rose with increasing severity of diabetes. Proteinuria early in pregnancy was associated with marked increases in adverse neonatal outcomes independent of preeclampsia development. (Am J Obstet Gynecol 2000;182:364-9.)

Antibiotic treatment in preterm labor and intact membranes: A randomized, double‐blinded, placebo‐controlled trial

Although an association between microbial invasion of amniotic cavity and preterm birth has been extensively demonstrated, there is conflicting evidence regarding the benefits of antibiotic therapy in patients with preterm labor and intact membranes. We attempted to assess the efficacy of amoxicillin and erythromycin on pregnancy outcome in those patients. A randomized, double-blinded, placebo-controlled trial was designed and implemented. A total of 196 patients with singleton pregnancies and preterm labor with intact membranes (22–36 weeks) were randomly allocated to receive either antibiotics or placebo, plus adjunctive parenteral tocolysis, and 173 patients (antibiotics group n = 83 vs. placebo group n = 90) completed the treatment. The overall prevalence of microbial invasion of the amniotic cavity was 5.2% (9/173). No significant difference between both groups was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery, and frequency of clinical chorioamnionitis and endometritis. Rate of cesarean section was significantly higher in the placebo group (28% vs. 12%). Regarding neonatal outcome, no significant difference was detected between both groups in neonatal death, respiratory distress syndrome, proven sepsis, and birthweight. Suspected sepsis was significantly more frequent in the placebo group (6/90 vs. 0/78). The results of this trial indicate that amoxicillin and erythromycin do not prolong pregnancy in patients with preterm labor and intact membranes. A significant reduction in the rate of cesarean section was observed in patients receiving antibiotics. A significant reduction in the rate of neonatal suspected sepsis was also demonstrated. J. Matern.-Fetal Med. 7:105–110, 1998. © 1998 Wiley-Liss, Inc.

Antibiotic treatment in preterm labor and intact membranes: A randomized, double-blinded, placebo-controlled trial

Although an association between microbial invasion of amniotic cavity and preterm birth has been extensively demonstrated, there is conflicting evidence regarding the benefits of antibiotic therapy in patients with preterm labor and intact membranes. We attempted to assess the efficacy of amoxicillin and erythromycin on pregnancy outcome in those patients. A randomized, double-blinded, placebo-controlled trial was designed and implemented. A total of 196 patients with singleton pregnancies and preterm labor with intact membranes (22–36 weeks) were randomly allocated to receive either antibiotics or placebo, plus adjunctive parenteral tocolysis, and 173 patients (antibiotics group n = 83 vs. placebo group n = 90) completed the treatment. The overall prevalence of microbial invasion of the amniotic cavity was 5.2% (9/173). No significant difference between both groups was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery, and frequency of clinical chorioamnionitis and endometritis. Rate of cesarean section was significantly higher in the placebo group (28% vs. 12%). Regarding neonatal outcome, no significant difference was detected between both groups in neonatal death, respiratory distress syndrome, proven sepsis, and birthweight. Suspected sepsis was significantly more frequent in the placebo group (6/90 vs. 0/78). The results of this trial indicate that amoxicillin and erythromycin do not prolong pregnancy in patients with preterm labor and intact membranes. A significant reduction in the rate of cesarean section was observed in patients receiving antibiotics. A significant reduction in the rate of neonatal suspected sepsis was also demonstrated.

Management options in women with preterm uterine contractions: A randomized clinical trial

OBJECTIVE: Our purpose was to evaluate three management strategies and to assess pregnancy outcomes in women with preterm uterine contractions. STUDY DESIGN: Consenting women seen in our hospital triage area with preterm uterine contractions were randomly assigned to observation alone, intravenous hydration, or one dose of subcutaneous terbutaline sulfate (0.25 mg). Eligible women had a singleton gestation between 20 and 34 weeks, intact membranes, more than three contractions in 30 minutes, and a cervical dilation ≤1 cm and effacement <80%. Women who had progressive cervical change at <34 weeks were treated with intravenous tocolysis. Women with recurrent preterm uterine activity remained in their assigned group during subsequent triage visits. RESULTS: One hundred seventy-nine women were randomized: observation (56), hydration (62), and terbutaline (61). Women in these three groups were similar with respect to maternal age, race, parity, prior preterm births, gestational age at randomization, contraction frequency, and mean cervical dilatation. There were no intergroup differences in the mean days to delivery, the number of repeat triage visits, the incidence of preterm labor at <34 weeks, or the frequency of preterm deliveries at <34 weeks and <37 weeks. Women assigned to terbutaline had contractions stopped and were discharged earlier (terbutaline 4.1 ± 5.1 hours, observation 5.2 ± 5.3 hours, hydration 6.0 ± 5.7 hours; p = 0.006). No complications of therapy were observed. CONCLUSIONS: The use of intravenous hydration in the management of preterm contractions was of no benefit. The use of one dose of subcutaneous terbutaline resulted in the shortest length of triage stay but did not affect pregnancy outcome. (Am J Obstet Gynecol 1997;177:814-8.)

First trimester chorionic villus sampling in twin gestations.

First-trimester prenatal diagnosis was offered to 104 twin pregnancies mainly for advanced maternal age and cytogenetic evaluation of a new fertilization technique. Chorionic villus sampling (CVS) was performed transcervically (35%), transabdominally (23%), or by combination of these two techniques (42%). Although no placental biopsy failures occurred, two errors in fetal sexing were recorded due to non-selective placental sampling. In these two cases, both fetuses were sampled transcervically. Cytogenetic results were available for all fetuses; six of them showed an abnormal direct chromosomal pattern, but long-term villi culture analysis or additional amniocentesis (n = 1) reduced the number to four. Early fetal loss (3.4%) and perinatal mortality (6.3%) after CVS were comparable with a control group of 101 consecutive twin pregnancies without prenatal diagnosis (respectively 6.9% and 5.3%). Perinatal loss in the CVS group was associated in 10 of 12 fetuses with preterm premature rupture of the membranes and consequent preterm delivery. Mean gestational age at delivery, mean birthweight and the frequency of preterm delivery, and low birthweight infants were nearly identical in both groups. This study shows that CVS in the first trimester of pregnancy is an accurate and fast approach for prenatal diagnosis in twin gestations with an acceptable risk of adverse pregnancy outcome. However, a transcervical approach for both fetuses is not recommended.

The underlying cause of polyhydramnios determines prematurity.

The preterm delivery rate in polyhydramnios is higher than in the normal population. We conducted this study to determine if different aetiologies for polyhydramnios have different frequencies of preterm delivery. Three hundred and forty women with a singleton pregnancy and polyhydramnios were included in the study group. A delivery was considered premature if it occurred before 37 weeks' gestation. Preterm deliveries occurred in 14.1 per cent of patients with unexplained polyhydramnios, 27.7 per cent of patients with insulin-dependent diabetes mellitus (IDDM), and in 36 per cent of pregnancies with congenital malformations. The prevalence of preterm delivery was significantly greater for the subgroups with IDDM (P = 0.02) and congenital malformations (P = 0.001), when compared with patients with idiopathic polyhydramnios. The prevalence of preterm delivery in patients with gestational diabetes mellitus was no greater than for the population at large. The underlying cause of polyhydramnios is a major factor in determining when delivery will occur.

Antibiotic treatment of preterm labor with intact membranes: A multicenter, randomized, double-blinded, placebo-controlled trial

Although an association between subclinical intrauterine infection and preterm birth is well established, there is conflicting evidence regarding the benefits of antibiotic administration to women in preterm labor with intact membranes. We attempted to determine the effect of ampicillin-amoxicillin and erythromycin treatment on prolongation of pregnancy, the rate of preterm birth, and neonatal morbidity in patients with preterm labor and intact membranes. A multicenter, randomized, double-blinded, placebo-controlled trial was designed and implemented by the Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development. Two hundred seventy-seven women with singleton pregnancies and preterm labor with intact membranes (24 to 34 weeks) were randomly allocated to receive either antibiotics or placebos. Of the 2373 patients screened for participation in this study in six medical centers, 277 women were enrolled (n = 133 for antibiotics group vs n = 144 for placebo group). In each study group, 60% of patients completed all the study medications. The overall prevalence of microbial invasion of the amniotic cavity was 5.8% (14/239). No significant difference between the antibiotic group and the placebo group was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery (< 37 weeks), frequency of preterm premature rupture of membranes, clinical chorioamnionitis, endometritis, and number of subsequent admissions for preterm labor. Similarly, no significant difference in neonatal outcomes could be detected between the two groups including respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, sepsis, and admission and duration of newborn intensive special care unit hospitalization. The results of this study do not support the routine use of antibiotic administration to women in preterm labor with intact membranes.

Reanalysis of a Muitireported Trial on Home Uterine Activity Monitoring

A randomized multicenter study of home uterine activity monitoring using the "Term Guard," is widely cited in support of the Term Guard monitoring system. Critical appraisal of the data in the six reports of the study showed that all reports scored poorly on avoidance of allocation, exclusion, and assessment bias. In all of them the numbers of women for whom outcomes were reported were different, and none provided information on infant outcomes. Comparison of analyses and subanalyses showed inconsistencies that defied the laws of arithmetic. Reanalysis of the data, as well as could be done from the available information, showed that use of the Term Guard system was compatible with both an increase and a decrease in the frequency of preterm delivery (95% CI +2.2% to -16.5%). It is concluded that the reports of the multicenter study contain such high potential for bias and so many internal inconsistencies that they should be dismissed entirely.

Schwangerschaftsverlauf bei Patientinnen mit Malignomen

There is a low incidence of pregnancy associated with malignancy. We performed a retrospective analysis of patients of 16 to 35 years of age with malignancies, who had given birth to children in Freiburg 1980-1989. 170 patients were included. 118 patients became pregnant before a malignancy was diagnosed. Malignancy was diagnosed during pregnancy in 24 patients, and 28 patients became pregnant after diagnosis of and therapy for neoplasm. The frequency of preterm delivery, growth retardation and performance of Caesarean section was markedly increased only in patients with concurrent pregnancy and malignancy. 59 children were born after their mother had been treated for a malignancy. Treatment was started during pregnancy in 19 cases. 40 children were born to mothers who became pregnant after treatment. Malformations and abnormalities with respect to the development of the children were observed in similar frequency in both groups and occurred more frequently compared to the group of children, who were born before the treatment of the mother. These results were supported by an analysis of 16 siblings. We conclude, that there is a demand for national and international registries for all pregnancies associated with malignancies. Long-time observation of the children born to mothers, who had been treated for malignancy are necessary.

Repeated fetal losses associated with antiphospholipid antibodies: A collaborative randomized trial comparing prednisone with low-dose heparin treatment

We attempted to compare the use of low-dose heparin with a standard dose of 40 mg prednisone daily (both plus low-dose aspirin) for treatment of pregnant women with antiphospholipid antibody-associated recurrent fetal loss with respect to maternal and perinatal morbidity and efficacy in prevention of fetal death. A multicenter randomized trial included 20 patients. Generalizability of results from randomized patients was evaluated by means of additional data from 13 women refusing and 12 women ineligible for randomization. Data from study groups were compared with Fisher's exact test, and generalizability was evaluated with a chi 2 test for trend. Live birth rates were the same (75%) with either treatment, but "serious" maternal morbidity and the frequency of preterm delivery were significantly higher among women randomly assigned to prednisone (p = 0.02 vs p = 0.006). Preterm delivery among prednisone-treated women was usually associated with premature rupture of the membranes or preeclampsia. These results could be generalized to the other groups of women ascertained during the course of the study. Low-dose heparin should be preferred to prednisone when treatment is indicated for high-risk pregnant women with antiphospholipid antibodies.

Schwangerschaftshypotonie

Maternal and foetal risk of hypotension in pregnancy were examined in a prospective study, comprising a total of 770 pregnant women i.e. 700 normotensives and 70 hypotensives. We conducted a minimum of 5 pressure controls beginning after the 20th week of gestation. All pressure controls were conducted by the same person and in each control 4 pressure values were taken (left and right arm, lying, standing). No difference was discovered in the statistical analysis of our data of pregnancy, delivery and foetal outcome. Our special interest was in the frequency of preterm delivery and foetal growth retardation. The rate was similar in the hypotensive group (6.7/3.1%) compared to the normotensive group (6.8/2.8%). From our results we conclude, that maternal hypotension is not a risk factor in pregnancy, and that no therapy is needed.

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. III. Historical study of pregnancy outcomes

We related perinatal outcome and quality of prenatal care between 1972 and 1980 to WIC benefits to pregnant women among 11,154,673 births in 1392 counties in 19 states and the District of Columbia, adjusted for time change and between-county variability. WIC was associated with increased first trimester prenatal care (4.1%, p less than 0.001), decreased inadequate prenatal care (-5.0%, p less than 0.001), longer duration of gestation (0.20 d, p less than 0.05), decreased preterm delivery (-0.92%, p less than 0.05) and increased birth weight (23 g, p less than 0.01). After autocorrelation was accounted for, significance levels for birth weight and frequency of preterm delivery were 0.05 less than p less than 0.10. Including counties with incomplete time series data, the estimated effect on birth weight was 23.9 g (p = 0.004) and on decreased fetal mortality was -2.3/1000 (p = 0.04). Among those with less than 12 y schooling, whites had a 1.8% reduction in preterm birth (p less than 0.05) and blacks a 2.0% reduction (p less than 0.05). The estimated effect on birth weight for less-educated whites was 46.6 g (p less than 0.001). The predominant effects of WIC were on improved physiologic status of the mother and fetus.

Patterns of alcohol consumption during pregnancy

Alcohol consumption among 530 pregnant women was recorded retrospectively from the last menstrual period to a mean of ten gestational weeks, and thereafter prospectively to term. Fifty-five percent of women had drunk alcohol (average 66 g of ethanol) during the week when ovulation was assumed to have taken place. This was not significantly different from the figures in 100 women seeking contraception, of whom 72% drank on average 61 g of ethanol during the ovulation week. Ninety percent of women drank alcohol at least once after the diagnosis of pregnancy. Drinking more than 600 g of ethanol during the first 12 gestational weeks (about four drinks weekly) was associated with an increased frequency of preterm delivery (P less than .05), but fetal outcome was not compromised. The proportion of drinking women decreased with advancing gestational age, with only 50% drinking after 32 weeks and only 20% during the last week of gestation. Beer was most commonly consumed, followed by wine and liquor. Alcohol consumption during pregnancy ranged between 7 and 4440 g, but 90% of the subjects drank less than 1100 g (zero to two drinks per week). Thus, women tended to decrease their drinking during pregnancy. Fewer than two drinks weekly had no detectable adverse effects on the fetal outcome.

Bed Rest in Twin Pregnancy

A total of 146 twin pregnancies were studied to evaluate the importance of bed rest. A significantly reduced frequency of preterm delivery was found after bed rest in hospital as compared to bed rest at home or no bed rest at all. An increase in gestational age and in birth weight was seen after bed rest. No effect was found on the intrauterine increase of fetal weight per time. Early routine ultrasound is recommended, so that effective bed rest may be instituted in due time.

Rh immune globulin after genetic amniocentesis: impact on pregnancy outcome.

Although Rh immune globulin is commonly given to Rh-negative women undergoing genetic amniocentesis, there is little documentation of the necessity, efficacy, or safety of this policy. In this study, reproductive outcomes in 147 women each receiving 150 micrograms of Rh immune globulin after genetic amniocentesis were compared with those of an equal number of Rh-positive amniocentesis control women. No significant differences were found in the incidence of midtrimester pregnancy loss, mean gestational age at delivery, mean birth weight, or frequency of preterm deliveries (P greater than 0.05 for all parameters). While two antepartum stillbirths occurred in the study group and none in the control population, causes unrelated to Rh immune globulin administration were apparent for both fetal deaths (one multiple congenital anomaly syndrome, one abruptio placentae at 38 weeks). Of the 103 Rh-negative women giving birth to Rh-positive infants, none were overtly sensitized at the time of delivery. It is concluded that second trimester Rh immune globulin administration does not increase the risk of pregnancy loss.