Comparison of late-second-trimester nonstress test characteristics between small for gestational age and appropriate for gestational age infants

OBJECTIVE: To compare electronic fetal heart rate (FHR) monitoring characteristics between appropriate for gestational age (AGA) fetuses and small for gestational age (SGA) fetuses and to determine whether SGA fetuses have specific abnormalities at second-trimester electronic fetal monitoring (EFM), using nonstress test. METHODS: Among 953 children born from 1993-1996, we identified 500 singleton infants born after 36 weeks' gestation of uncomplicated pregnancies in whom second-trimester (24-27 weeks' gestation) EFM records were obtained. Individual components of FHR patterns (baseline rate, baseline FHR variability, presence of acceleration [at least 10 beats per minute for at least 10 seconds], and periodic or episodic deceleration [at least 25 beats per minute for at least 15 seconds]) and birth characteristics were compared between AGA and SGA infants, or between pregnancies with or without second-trimester decelerations. RESULTS: Among 500 infants, 443 were AGA and 57 SGA; 105 had and 395 did not have second-trimester decelerations. Baseline FHR variability (12.9+/-3.2 beats per minute) in SGA fetuses was significantly higher than variability (10.3+/-3.4 beats per minute) in AGA fetuses (P<.001). Small for gestational age fetuses were significantly more likely to have second-trimester decelerations than AGA fetuses (33.3% vs. 19.4%, P<.05). There were no significant differences in baseline rate and accelerations between AGA and SGA infants. Small for gestational age infants were more frequent in pregnancies with second-trimester decelerations, compared with those without second-trimester decelerations (18.1% vs. 9.6%, P<.05). Baseline FHR variability in pregnancies with second-trimester decelerations was significantly higher than in pregnancies without second-trimester decelerations (12.2+/-3.7 vs. 10.0+/-3.1 beats per minute, P<.001). CONCLUSION: Periodic or episodic decelerations and increased FHR variability during late second-trimester EFM were associated with an increased risk of SGA birth weight.     

Computerized analysis of the fetal heart rate in pregnancies complicated by preterm premature rupture of membranes (pPROM).

OBJECTIVE: We aimed to show that in pregnancies complicated by preterm premature rupture of membranes (pPROM), there are alterations to the fetal heart rate pattern that can be detected by computerized analysis. METHODS: The study population consisted of 27 pregnant women with pPROM at 29-34 weeks of gestation and 33 normal pregnancies matched according to age, parity and gestation. A 30-minute fetal heart rate (FHR) tracing was analyzed by computer and umbilical artery cord blood was collected at birth. RESULTS: The baseline heart rate, the number of decelerations exceeding 20 beats per minute and the duration of episodes of low variation were higher in the pPROM group versus the controls. The number of decelerations exceeding 20 beats per minute had an independent, statistically significant association with umbilical artery pH at birth. CONCLUSIONS: Even if our data require a prospective validation involving a larger number of pathological cases, a computerized FHR tracing analysis may improve the clinical care and the timing of delivery during pPROM by definition of the risk of acidemia and pre-acidemia.     

Cervical dimensions and risk of preterm birth: a prospective cohort study

OBJECTIVE: To examine the relation between cervical dilatation and length and the risk of spontaneous preterm birth, including its subtypes preterm labor and preterm premature rupture of membranes (PROM). METHODS: Cervical dimensions assessed by clinical examination were recorded prospectively at 24-29 weeks' gestation in 871 subjects with singleton pregnancies who were followed to delivery. Relative risks (RRs) of preterm birth, preterm labor, and preterm PROM were calculated for clinically distinguishable categories of cervical dilatation and length and for cervical score (length minus dilatation). Regression analysis was used to adjust for confounding. Time to delivery from baseline examination was summarized using survival analysis. RESULTS: There were 73 spontaneous preterm births (8.3%), 46 preterm labors and 27 cases of preterm PROM. All cervical measurements were associated with increased risks of preterm birth, with increasing abnormality more strongly predictive of risk. The adjusted RR for preterm birth with dilatation of at least 0.5 cm was 2.9 (95% confidence interval [CI] 1.2, 7.3); for length of 1.5 cm or less, the RR was 2.1 (95% CI 1.0, 4.5), and for cervical score less than 2.0, the RR was 2.8 (95% CI 1.4, 5.6). The association with cervical measurements was stronger for preterm PROM than for preterm labor, although precision was limited. These measurements had high specificity (93-99%) and low sensitivity (8-20%) for predicting preterm birth. CONCLUSION: In asymptomatic women at 24-29 weeks' gestation, greater cervical dilatation and shorter length were associated with increased risk of spontaneous preterm delivery, particularly preterm PROM.     

Preterm premature rupture of membranes: is there an optimal gestational age for delivery?

OBJECTIVE: To characterize neonatal and maternal morbidity and mortality rates in pregnancies complicated by preterm premature rupture of membranes (PROM) and determine whether there is an optimal delivery gestational age. METHODS: We reviewed maternal and neonatal outcomes of women with PROM 24 weeks or more that resulted in delivery at less than 37 weeks at our institution from August 1998 to August 2000. Standardized management included the use of antibiotics, betamethasone at less than 32 weeks, and expectant management until 24 weeks or more. Outcomes evaluated included neonatal mortality, composite major and minor neonatal morbidity, individual major and minor neonatal morbidity rates, maternal infection morbidity, and maternal and neonatal length of stay. Gestational age-specific maternal and neonatal outcomes were compared with a referent group of pregnancies complicated by preterm PROM that delivered between 36 0/7 and 36 6/7 weeks of gestation. RESULTS: During the study interval, 430 women with preterm PROM were identified. Composite major neonatal morbidity was significantly higher among pregnancies delivered at 33 weeks of gestation or less after preterm PROM as compared with those who delivered at 36 weeks. Composite neonatal minor morbidity was significantly higher among pregnancies delivered at 34 weeks or less after preterm PROM as compared with those who delivered at 36 weeks. However, there was no improvement in the composite major and minor neonatal morbidity rates for those pregnancies delivered beyond 34 weeks of gestation. Both maternal and infant length of stay were significantly longer for cases of preterm PROM delivered at 34 weeks or less as compared with those who delivered at 36 weeks. CONCLUSION: Our findings suggest that expectant management of women at 34 weeks and beyond is of limited benefit.     

第一产程异常胎心监护图形与新生儿结局的关系

目的　探讨第一产程异常胎心监护图形与新生儿结局的关系。方法　回顾分析 2 0 0 2年 8月至 2 0 0 3年 6月在我院足月单胎头位分娩产妇 ,第一产程中胎心率 (FHR)异常图形 2 1 7例 (观察组 )和FHR正常图形的2 6 9例 (对照组 )的临床资料。结果　第一产程异常FHR图形的发生率为 4 4 7% ,常见类型为轻度变异减速(6 4 5 % )、基线变异减弱 (2 1 6 % )和轻度心动过速 (1 2 0 % )。晚期减速、基线变异减弱和重度变异减速是导致新生儿窒息的危险因素。观察组羊水过少 (5 1 % )、脐带缠绕 (2 2 6 % )、羊水粪染 (1 0 6 % )、新生儿窒息 (6 5 % )、新生儿转入NICU(1 0 1 % )的发生率和剖宫产率 (31 8% )明显高于对照组 (P <0 0 5 )。结论　第一产程异常FHR图形的发生率较高 ,其中晚期减速、基线变异减弱、重度变异减速与新生儿窒息的发生相关 ,其他图形可在严密监护下继续试产     

The clinical interpretation and significance of electronic fetal heart rate patterns 2?h before delivery: an institutional observational study

Purpose

To evaluate the clinical significance of intrapartum fetal heart rate (FHR) monitoring in low-risk pregnancies according to guidelines and specific patterns.

Methods

An obstetrician, blinded to neonatal outcome, retrospectively reviewed 198 low-risk cases that underwent continuous electronic fetal monitoring (EFM) during the last 2?h before delivery. The tracings were interpreted as normal, suspicious or pathological, according to specific guidelines of EFM and by grouping the different FHR patterns considering baseline, variability, presence of decelerations and bradycardia. The EFM groups and the different FHR-subgroups were associated with neonatal acid base status at birth, as well as the short-term neonatal composite outcome. Comparisons between groups were performed with Kruskal–Wallis test. Differences among categorical variables were evaluated using Fisher’s exact test. Significance was set at p?<?0.05 level.

Results

Significant differences were found for mean pH values in the three EFM groups, with a significant trend from “normal” [pH 7.25, 95?% confidence interval (CI) 7.28–7.32] to “pathological” tracings (pH 7.20, 95?% CI 7.17–7.13). Also the rates of adverse composite neonatal outcome were statistically different between the two groups (p?<?0.005). Among the different FHR patterns, tracings with atypical variable decelerations and severe bradycardia were more frequently associated with adverse neonatal composite outcome (11.1 and 26.7?%, respectively). However, statistically significant differences were only observed between the subgroups with normal tracings and bradycardia.

Conclusions

In low-risk pregnancies, there is a significant association between neonatal outcome and EFM classification. However, within abnormal tracings, neonatal outcome might differ according to specific FHR pattern.     

Correlation between fetal heart rate reactivity and mortality and severe neurological morbidity in extremely low birth weight infants

Objective: To determine the correlation between specific fetal heart rate (FHR) abnormalities and the incidence of death, severe (grade 3–4) intraventricular hemorrhage (IVH) and periventricular echogenicity (PVE) in extremely low birth weight infants (ELBW) within the first 4 days after birth. Methods: The study included live-born ELBW infants ≤ 30 weeks’ gestation who were born in 2000–2007 at Kaplan Medical Center, Rehovot, Israel, and, who had FHR monitoring during the 24?h before delivery and cranial ultrasound during the first 4 days of life. FHR pattern was analyzed for the presence of baseline rate, reactivity, variability and decelerations. Results: 96 infants with mean birth weight 757?±?150?g and mean gestational age 25.8?±?1.5 weeks were included. By 4 days of life, 23/96 (24%) died, 17/96 (18%) developed severe IVH and 31/96 (32%) had PVE. Absence of reactivity was significantly associated with increase in both death (p?=?0.02, OR 3.45, 95% CI: 1.22–9.47 and severe IVH (p?=?0.029, OR 3.33, 95% CI: 1.25–10) but not with PVE. Other FHR parameters were not associated with adverse outcome. Conclusion: These results suggest that FHR reactivity may be of value in predicting short-term outcome in ELBW infants. This may be helpful in counseling parents with imminent extremely preterm birth.     

The very preterm infant - a population-based study

OBJECTIVES: The aim of this study was to assess perinatal risk factors and the survival of the very preterm infant in comparison with birth beyond 32nd birthweek, as well as health care utilization by mothers and infants in the Northern Health Region of Sweden. DESIGN: A population-based study was designed of all children (66,646) born in the Northern Health Region of Sweden during 1991-1996 and registered in the Swedish Medical Birth Registry. METHODS: Maternal and perinatal factors of infants born very preterm, that is, at < or =27 and 28-31 weeks of gestation, were analyzed for relative risk (RR), and a 95% confidence interval (CI), and compared with those of infants born 32-36 weeks of gestation. RESULTS: Of the 66,646 infants registered, 3,493 (5.2%) were born at 32-36 weeks, 394 (0.6%) at 28-31 weeks, and 199 (0.3%) at 22-27 weeks' gestation. No special socio-demographic maternal factors characterized these preterm births. The very preterm infants were more prone to perinatal complications such as premature rupture of the membranes (PROM) (RR=4.13; 95% CI=3.07-5.55), and both PROM and hemorrhage (RR=7.80; 95% CI=3.43-17.72). Infants born very preterm were more often twins, growth-retarded, malformed, and affected by sepsis and respiratory distress. There was significantly better survival of preterm infants born at < or =27 weeks' gestation if their mothers were given tertiary perinatal care. For infants born extremely preterm, survival tended to be better if they were delivered by cesarean section. CONCLUSION: The very preterm birth is more often than not a result of a complicated pregnancy. The infant is often sick before birth, and for its survival is highly dependent on the highest level of perinatal care.     

Immunoglobulin concentrations in newborn infants associated with intrauterine growth retardation

Immunoglobulin G, A, and M (IgG, IgA and IgM) levels were measured in paired maternal and cord serum samples from 18 pregnancies with intrauterine growth retardation (IUGR) and 55 with normal growth (adequate-for-gestational-age pregnancies) delivered vaginally at 36 weeks' gestation or later. Cord blood levels of IgG, IgA, and IgM in IUGR infants were found significantly lower than those in infants with adequate-for-gestational-age growth. Lower Lower levels of cord IgG in IUGR may be due to a defect in the active transport of IgG across the placenta. Lower levels of cord IgM and IgA suggest an impairment of synthesis of immunoglobulins in the IUGR infants. There was no difference in cord immunoglobulin concentrations between infants with intrapartum fetal heart rate (FHR) decelerations and those without FHR decelerations in either the IUGR or the adequate-for-gestational-age group. No difference was observed in maternal immunoglobulin concentrations among the study groups.     

Preterm deliveries among women with MacDonald cerclage performed due to cervical incompetence

OBJECTIVE: The study was aimed to assess the impact of obstetric risk factors for preterm delivery among women with MacDonald cerclage performed due to cervical incompetence. STUDY DESIGN: A cohort study was conducted including all patients with MacDonald cerclage performed at 12-14 weeks gestation due to cervical incompetence (n = 793). Deliveries occurred between the years 1988 and 2002 in a University Medical Center. A multiple linear regression model was used to assess the impact of maternal characteristics as well as pregnancy complications on the length of pregnancy. RESULTS: The following factors were found to be associated with preterm delivery among these patients, in the univariate analysis: nulliparity, fertility treatments, severe preeclampsia, second-trimester bleeding, premature rupture of membranes (PROM), chorioamnionitis and placental abruption. Using a multiple linear regression model, with backward elimination, the impact of these variables on the length of pregnancy was assessed (R(2) = 0.33, p < 0.001). The mean gestational age at birth among patients without risk factors was 38.1. Second-trimester bleeding reduced gestational age by 6.4 weeks, chorioamnionitis by 5.6 weeks, placental abruption by 5.1 weeks, PROM by 3.2 weeks and severe preeclampsia by 2.4 weeks. CONCLUSIONS: Second-trimester bleeding, chorioamnionitis, placental abruption, PROM and severe preeclampsia are ominous signs for preterm delivery among patients with MacDonald cerclage performed due to cervical incompetence.     

Risk of preterm delivery in singletons conceived by in vitro fertilization

To evaluate the preterm delivery and other obstetrics complications similar in singleton pregnancies achieved through IVF compared to spontaneous pregnancies. Retrospective case-control study included 1663 women with singleton pregnancies following IVF-ICSI (study group) and 3326 women with singleton spontaneous pregnancies (control group) who delivered between January 2015 and January 2018 at the Peking University Third Hospital. The control group matched 1:2 by age, BMI, parity, and gravidity. Maternal outcomes included preterm delivery and complications. There was significantly higher incidence of gestational diabetes, hypertensive disorders, and placenta previa in IVF-ICSI pregnancies versus controls (p?<?.05). IVF-ICSI resulted in significantly higher rate of preterm birth than in spontaneous pregnancies (p?<?.05) and the difference remained significant for deliveries that occurred before 28, 32, and 34?weeks gestation (p?<?.05). Multivariate logistic regression analysis revealed that female-factor infertility, hypertensive disorder, placenta previa, and PROM were significant prognostic factors associated with increased risk of prematurity. IVF-ICSI is associated with increased risk of obstetric complications including preterm delivery in singleton pregnancies. Female-factor infertility is an independent prognostic factor for preterm birth. This information is important for patient counseling and helps to refine the recommendation to optimize maternal health before embarking on fertility treatments.     

Course and predictive value of fetal heart rate parameters

The present study concerns the developmental character of the fetal heart rate (FHR) pattern and the implications of predicting the perinatal outcome. Data from 443 patients undergoing 2193 nonstress tests were analyzed retrospectively. We found a significant increase of accelerations more than 15 beats/min, of accelerations associated with fetal movements, of fetal movements registered by the tocotransducer, the frequency of oscillations, and of the Fischer score values throughout gestation. The number of short FHR decreases and the mean baseline level declined throughout gestation. A long duration of absent or reduced baseline variability registered even 6 weeks before delivery was associated with low Apgar score values. Late decelerations and contractions registered early in pregnancy were also correlated to a poor outcome. Tachycardia and a low number of accelerations were only correlated to a poor perinatal outcome shortly before the delivery. Fetal movements not associated with FHR accelerations were an early indicator of a poor neonatal outcome. Scoring systems did not generally improve the predictive value of FHR patterns.     

Heterogeneity of perinatal outcomes in the preterm delivery syndrome

OBJECTIVE: Our aim was to document the differential neonatal morbidity and intrapartum and neonatal mortality of subgroups of preterm delivery. METHODS: This analysis included 38,319 singleton pregnancies, of which 3,304 (8.6%) were preterm deliveries (less than 37 completed weeks) enrolled in the World Health Organization randomized trial of a new antenatal care model. We classified them as preterm deliveries after spontaneous initiation of labor, either with or without maternal obstetric and medical complications; preterm deliveries after prelabor spontaneous rupture of amniotic membranes (PROM), either with or without obstetric and medical complications; and medically indicated preterm deliveries with maternal obstetric and medical complications. Severe neonatal morbidity and neonatal mortality were the primary outcomes. RESULTS: Fifty-six percent of all preterm deliveries were spontaneous, without maternal complications. Small for gestational age was increased only among the medically indicated preterm delivery group (22.3%). Very early preterm delivery (less than 32 weeks of gestation) was highest among PROM with complications (37%). For intrapartum fetal death and neonatal death, after adjusting by gestational age and other confounding variables, we found that the obstetric and medical complications preceding preterm delivery predicted the different risk levels. Conversely, for severe neonatal morbidity the clinical presentation, ie, PROM or medically indicated, predicted the increased risk. CONCLUSION: There are differential neonatal outcomes among preterm deliveries according to clinical presentation, pregnancy complications, gestational age at delivery, and its association with small for gestational age. This syndromic nature of the condition should be considered if preterm delivery is to be fully understood and thus reduced.     

The effect of loop electrosurgical excision procedure on future pregnancy outcome

OBJECTIVE: To estimate whether the loop electrosurgical excision procedure (LEEP) is associated with an adverse effect on the outcome of subsequent pregnancies. METHODS: A retrospective cohort study was performed. The study group comprised women who had a LEEP in Halifax County between 1992 and 1999 and then had a subsequent singleton pregnancy of greater than 20 weeks of gestation with delivery at the IWK Health Centre in Halifax, Nova Scotia. The comparison group comprised women with no history of cervical surgery who were matched for age, parity, smoking status, and year of delivery. There were 571 women in each group. The primary outcome was rate of preterm delivery at less than 37 weeks of gestation. Secondary outcomes included delivery at less than 34 weeks and various neonatal and maternal outcomes. The effect of specific LEEP characteristics was analyzed separately. RESULTS: Women who had a LEEP were more likely to deliver preterm overall (7.9% versus 2.5%; odds ratio [OR] 3.50, 95% confidence interval [CI] 1.90-6.95; P < .001) and to deliver preterm after premature rupture of membranes (PROM) (3.5% versus 0.9%; OR 4.10, 95% CI 1.48-14.09). The increase in delivery at less than 34 weeks was not statistically significant (1.25% versus 0.36%; OR 3.50, 95% CI 0.85-23.49; P = .12). Women with LEEP also delivered more low birth weight (LBW) infants (5.4% versus 1.9%; OR 3.00, 95% CI 1.52-6.46; P = .003). There were no differences in other neonatal or maternal outcomes. No association was found between the characteristics of the LEEP, including depth, and the rate of preterm delivery. CONCLUSION: Loop electrosurgical excision procedure is associated with an increased risk of overall preterm delivery, preterm delivery after PROM, and LBW infants in subsequent pregnancies at greater than 20 weeks of gestation. Women who are considering future pregnancies should be counseled about these risks during informed consent for LEEP. LEVEL OF EVIDENCE: II-2.     

Pregnancy outcome after multifetal pregnancy reduction.

OBJECTIVE: To study the effects of multifetal pregnancy reduction (MFPR) as a means to reduce the adverse outcome of multiple gestations. METHODS: This was a retrospective study evaluating the outcome of 334 multiple pregnancies after embryo reduction. RESULTS: In 313 multiple pregnancies in which MFPR was performed before 15 weeks, the rates of miscarriage, preterm delivery <33 weeks, preterm delivery <36 weeks and total fetal loss were 9.12%, 13.33%, 38.60% and 16.25%, respectively, and median gestational age at delivery was 35 weeks. There was a significant correlation between miscarriage and the finishing number of fetuses. In 185 triplets reduced to twins, miscarriage, preterm delivery <33 weeks, preterm delivery <36 weeks and total fetal loss occurred in 8.25%, 11.18%, 40.59% and 15.41% of cases, respectively, and median gestational age at delivery was 36 weeks. In the subgroup of 32 reduced triplet pregnancies that also had second-trimester amniocentesis, the risk of miscarriage (3.13%) was not significantly different from that in the rest of the group. Among 21 twin pregnancies that had selective termination at or after 15 weeks, the risk of preterm delivery <33 weeks was three times higher than in the group of 22 twin pregnancies with first-trimester procedures. CONCLUSION: MFPR resulted in at least one live neonate in 83.75% of cases and was effective in reducing the risks of pregnancy loss and severe prematurity in quadruplets and higher-order pregnancies. The risk of miscarriage increased with increasing finishing number of fetuses. In reduced triplets gestation was prolonged in comparison with average figures reported in the literature. In twin pregnancies selective termination in the first trimester carries a lower risk of severe preterm delivery and this emphasizes the need for first-trimester diagnosis.     

Computerized fetal heart rate analysis in labor

Observer variation in visual analysis of fetal heart rate (FHR) records is reportedly high, but can be avoided by computerized numerical analysis. The FHRs of 394 women in labor at 37 or more weeks' gestation were recorded on-line and analyzed to examine how different patterns related to outcome, as judged by umbilical arterial base deficit or Apgar score on delivery. The range of normality and the diversity of patterns of those delivered without acidemia were great. Late decelerations were of poor prognostic value. There was an increase in FHR variation during labor averaging 40%. In this preliminary study, conventional attributes of the FHR, alone or in combination, did not predict metabolic acidemia. Epidural analgesia in 240 women was identified as a confounding variable that significantly affected FHR patterns without influencing the condition of the infant at birth. It was associated with a higher FHR, less FHR variation and fewer decelerations, primiparity, longer labors, more operative deliveries, and a threefold greater cesarean rate. The rise in basal FHR, perhaps due to a rise in maternal temperature, may partly explain the high intervention rate in those without fetal acidemia.     

Deceleration area of fetal heart rate trace and fetal acidemia at delivery: a case-control study.

OBJECTIVE: To assess the correlation between the total deceleration area of the fetal heart rate (FHR) pre-delivery trace and intrapartum fetal acid-base status in a low risk population. STUDY DESIGN: We analyzed the electronic fetal monitoring (EFM) traces of 26 pregnancies with fetuses presenting acidemia at delivery and those of thirty controls. All laboring patients had at least 1 hour of EFM without interruption. The deceleration area was calculated, after digital analysis, with Autocad System 2004. RESULTS: We found that the number of decelerations (8.03 +/- 3.77 vs. 4.64 +/- 3.84) and the total deceleration area/hour (35.56 +/- 11.87 vs. 17.81 +/- 9.38) were significantly higher in the study group than in the control group. CONCLUSIONS: Our results show that quantitative analysis of the deceleration areas by digitized cardiotocography may have a discriminative capacity to predict fetal acidemia at delivery.     

The clustering of fetal heart rate changes and fetal movements in pregnancies between 20 and 30 weeks of gestation

The temporal organization (nonrandomness) of fetal heart rate (FHR), fetal movement, and their association was evaluated in 20 normal pregnancies at 20 to 22 or 28 to 30 weeks of gestation with the use of external electronic fetal monitoring and statistical analysis with the runs test. At 20 to 22 weeks, significant clustering was found in one of 10 pregnancies for FHR change, two of 10 pregnancies for fetal movement, and one of 10 pregnancies for FHR changes associated with fetal movement. At 28 to 30 weeks, significant clustering was found in eight of 10 pregnancies for FHR change, eight of 10 pregnancies for fetal movement, and uli 10 pregnances for FHR change associated with fetal movement. There was significantly more clustering of FHR change, fetal movement, and FHR change associated with fetal movement at 28 to 30 weeks of gestation than at 20 to 22 weeks of gestation. Clustering of FHR changes was highly correlated with clustering of fetal movement.     

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.