Repeated cervical length measurements for the verification of short cervical length.

OBJECTIVE: To determine if the verification of short cervical length with a repeated measurement improved the identification of patients with short cervical length at increased risk of preterm delivery. METHODS: The present secondary analysis analyzed prospective cohort study data from patients with singleton pregnancies without a history of preterm delivery who presented for obstetric care in the Netherlands and delivered between November 18, 2009, and January 1, 2013. Cervical length was measured during standard anomaly scan and a second measurement was performed if the cervical length was 30 mm of shorter. Logistic regression and Cox proportional hazards modeling were used to evaluate associations between cervical length measurements and spontaneous preterm delivery before 37 weeks of pregnancy. RESULTS: Cervical length measurements from 12 358 patients were included; 221 (1.8%) had an initial cervical length measurement of 30 mm or shorter. A second cervical length measurement was performed for 167 (75.6%) patients; no differences were identified in the odds of spontaneous preterm delivery when evaluated using the first, second, or a mean of both measurements, regardless of whether cervical length was analyzed as a continuous or dichotomous variable. CONCLUSION: Among patients with singleton pregnancies, verification of short cervical length did not improve the identification of short cervical length.

The capacity of mid-pregnancy cervical length to predict preterm birth in low-risk women: a national cohort study.

INTRODUCTION: We investigated the predictive capacity of mid-trimester cervical length (CL) measurement for spontaneous and iatrogenic preterm birth. MATERIAL AND METHODS: We performed a prospective observational cohort study in nulliparous women and low-risk multiparous women with a singleton pregnancy between 16(+0) and 21(+6) weeks of gestation. We assessed the prognostic capacity of transvaginally measured mid-trimester CL for spontaneous and iatrogenic preterm birth (<37 weeks) using likelihood ratios (LR) and receiver-operating-characteristic analysis. We calculated numbers needed to screen to prevent one preterm birth assuming different treatment effects. Main outcome measures were preterm birth <32, <34 and <37 weeks. RESULTS: We studied 11,943 women, of whom 666 (5.6%) delivered preterm: 464 (3.9%) spontaneous and 202 (1.7%) iatrogenic. Mean CL was 44.1 mm (SD 7.8 mm). In nulliparous women, the LRs for spontaneous preterm birth varied between 27 (95% CI 7.7-95) for a CL ≤ 20 mm, and 2.0 (95% CI 1.6-2.5) for a CL between 30 and 35 mm. For low-risk multiparous women, these LRs were 37 (95% CI 7.5-182) and 1.5 (95% CI 0.97-2.2), respectively. Using a cut-off for CL ≤ 30 mm, 28 (6.0%) of 464 women with spontaneous preterm birth were identified. The number needed to screen to prevent one case of preterm birth was 618 in nulliparous women and 1417 for low-risk multiparous women (40% treatment effect, cut-off 30 mm). CONCLUSION: In women at low risk of preterm birth, CL predicts spontaneous preterm birth. However, its isolated use as a screening tool has limited value due to low sensitivity.

Maternal and neonatal consequences of treated and untreated asymptomatic bacteriuria in pregnancy: a prospective cohort study with an embedded randomised controlled trial.

BACKGROUND: Existing approaches for the screening and treatment of asymptomatic bacteriuria in pregnancy are based on trials that were done more than 30 years ago. In this study, we reassessed the consequences of treated and untreated asymptomatic bacteriuria in pregnancy. METHODS: In this multicentre prospective cohort study with an embedded randomised controlled trial, we screened women (aged ≥18 years) at eight hospitals and five ultrasound centres in the Netherlands with a singleton pregnancy between 16 and 22 weeks' gestation for asymptomatic bacteriuria. Screening was done with a single dipslide and two culture media. Dipslides were judged positive when the colony concentration was at least 1×10(5) colony-forming units (CFU) per mL of a single microorganism or when two different colony types were present but one had a concentration of at least 1×10(5) CFU per mL. Asymptomatic bacteriuria-positive women were eligible to participate in the randomised controlled trial comparing nitrofurantoin with placebo treatment. In this trial, participants were randomly assigned 1:1 to receive either nitrofurantoin 100 mg or identical placebo tablets, and were instructed to self-administer these tablets twice daily for 5 consecutive days. Randomisation was done by a web-based application with a computer-generated list with random block sizes of two, four, or six participants rendered by an independent data manager. 1 week after the end of treatment, they provided us with a follow-up dipslide. Women, treating physicians, and researchers all remained unaware of the bacteriuria status and treatment allocation. Women who refused to participate in the randomised controlled trial did not receive any antibiotics, but their outcomes were collected for analysis in the cohort study. We compared untreated and placebo-treated asymptomatic bacteriuria-positive women with asymptomatic bacteriuria-negative women and nitrofurantoin-treated asymptomatic bacteriuria-positive women. The primary endpoint was a composite of pyelonephritis with or without preterm birth at less than 34 weeks, analysed by intention to treat at 6 weeks post-partum. This trial is registered with the Dutch Trial Registry, number NTR3068. FINDINGS: Between Oct 11, 2011, and June 10, 2013, we enrolled 5621 women into our screening cohort, of whom 5132 were eligible for screening. After exclusions for contaminated dipslides and patients lost to follow-up, in our final cohort of 4283 women, 248 were asymptomatic bacteriuria positive, of whom 40 were randomly assigned to nitrofurantoin and 45 to placebo for the randomised controlled trial, whereas the other 163 asymptomatic bacteriuria-positive women were followed without treatment. The proportion of women with pyelonephritis, preterm birth, or both did not differ between untreated or placebo-treated asymptomatic bacteriuria-positive women and asymptomatic bacteriuria-negative women (6 [2·9%] of 208 vs 77 [1·9%] of 4035; adjusted odds ratio [OR] 1·5, 95% CI 0·6-3·5) nor between asymptomatic bacteriuria-positive women treated with nitrofurantoin versus those who were untreated or received placebo (1 [2·5%] of 40 vs 6 [2·9%] of 208; risk difference -0·4, 95% CI -3·6 to 9·4). Untreated or placebo-treated asymptomatic bacteriuria-positive women developed pyelonephritis in five [2·4%] of 208 cases, compared with 24 [0·6%] of 4035 asymptomatic bacteriuria-negative women (adjusted OR 3·9, 95% CI 1·4-11·4). INTERPRETATION: In women with an uncomplicated singleton pregnancy, asymptomatic bacteriuria is not associated with preterm birth. Asymptomatic bacteriuria showed a significant association with pyelonephritis, but the absolute risk of pyelonephritis in untreated asymptomatic bacteriuria is low. These findings question a routine screen-treat-policy for asymptomatic bacteriuria in pregnancy. FUNDING: ZonMw (the Netherlands Organisation for Health Research and Development).

Costs and effects of screening and treating low risk women with a singleton pregnancy for asymptomatic bacteriuria, the ASB study.

BACKGROUND: The prevalence of asymptomatic bacteriuria (ASB) in pregnancy is 2-10% and is associated with both maternal and neonatal adverse outcomes as pyelonephritis and preterm delivery. Antibiotic treatment is reported to decrease these adverse outcomes although the existing evidence is of poor quality. METHODS/DESIGN: We plan a combined screen and treat study in women with a singleton pregnancy. We will screen women between 16 and 22 weeks of gestation for ASB using the urine dipslide technique. The dipslide is considered positive when colony concentration ≥105 colony forming units (CFU)/mL of a single microorganism or two different colonies but one ≥105 CFU/mL is found, or when Group B Streptococcus bacteriuria is found in any colony concentration. Women with a positive dipslide will be randomly allocated to receive nitrofurantoin or placebo 100 mg twice a day for 5 consecutive days (double blind). Primary outcomes of this trial are maternal pyelonephritis and/or preterm delivery before 34 weeks. Secondary outcomes are neonatal and maternal morbidity, neonatal weight, time to delivery, preterm delivery rate before 32 and 37 weeks, days of admission in neonatal intensive care unit, maternal admission days and costs. DISCUSSION: This trial will provide evidence for the benefit and cost-effectiveness of dipslide screening for ASB among low risk women at 16-22 weeks of pregnancy and subsequent nitrofurantoin treatment. TRIAL REGISTRATION: Dutch trial registry: NTR-3068.

Preventing preterm birth with progesterone: costs and effects of screening low risk women with a singleton pregnancy for short cervical length, the Triple P study.

BACKGROUND: Women with a short cervical length in mid-trimester pregnancy have a higher risk of preterm birth and therefore a higher rate of neonatal mortality and morbidity. Progesterone can potentially decrease the number of preterm births and lower neonatal mortality and morbidity. Previous studies showed good results of progesterone in women with either a history of preterm birth or a short cervix. However, it is unknown whether screening for a short cervix and subsequent treatment in mid trimester pregnancy is effective in low risk women. METHODS/DESIGN: We plan a combined screen and treat study among women with a singleton pregnancy without a previous preterm birth. In these women, we will measure cervical length at the standard anomaly scan performed between 18 and 22 weeks. Women with cervical length ≤ 30 mm at two independent measurements will be randomly allocated to receive either vaginal progesterone tablets or placebo between 22 and 34 weeks. The primary outcome of this trial is adverse neonatal condition, defined as a composite outcome of neonatal mortality and severe morbidity. Secondary outcomes are time to delivery, preterm birth rate before 32, 34 and 37 weeks, days of admission in neonatal intensive care unit, maternal morbidity, maternal admission days for preterm labour and costs. We will assess growth, physical condition and neurodevelopmental outcome of the children at two years of age. DISCUSSION: This study will provide evidence for the usefulness and cost-effectiveness of screening for short cervical length at the 18-22 weeks and subsequent progesterone treatment among low risk women. TRIAL REGISTRATION: Netherlands Trial Register (NTR): NTR207.