Cerclage for Short Cervix on Ultrasonography

Transvaginal cervical length scans to prevent prematurity in twins: a randomized controlled trial

BACKGROUND

Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23% of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity.

OBJECTIVE

We sought to determine whether use of TVCL prolongs gestation in twin pregnancies.

STUDY DESIGN

This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes.

RESULTS

The mean gestational age at delivery was 35.7 weeks (95% confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95% CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P = .67), Breslow test (P = .67), or Tarone-Ware test (P = .64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4% for subjects managed with routine TVCL and 28.6% for control subjects (relative risk, 0.96; 95% CI, 0.60-1.54). Our study had an 80% power to detect a 12-day difference in the gestational age at delivery with 95% confidence.

CONCLUSION

The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.

Cervical pessary to prevent preterm birth in women with twin gestation and sonographic short cervix: a multicenter randomized controlled trial (PECEP-Twins)

BACKGROUND

Spontaneous preterm birth (SPB) is the leading cause of perinatal morbidity and mortality. In twins, the rate of preterm birth is higher than in singletons; interventions to prevent preterm birth are needed in this high-risk population.

OBJECTIVE

We sought to test whether a cervical pessary reduces the preterm birth rate in twin pregnancies with sonographic short cervix.

STUDY DESIGN

A prospective, open-label, multicenter, randomized clinical trial was conducted in 5 hospitals in Spain. The ethics committees of all participating hospitals approved the protocol. The trial was registered as ClinicalTrials.gov, number NCT01242410. Eligible women were scanned in Spain. The primary outcome was SPB <34 weeks of gestation. Neonatal morbidity and mortality were also evaluated.

RESULTS

Cervical length was measured in 2287 women; 137 pregnant women with a sonographic cervical length ≤25 mm (of 154 detected with a short cervix) were randomly assigned to receive a cervical pessary or expectant management (1:1 ratio). SPB <34 weeks of gestation was significantly less frequent in the pessary group than in the expectant management group (11/68 [16.2%] vs 26/66 [39.4%]; relative risk, 0.41; 95% confidence interval, 0.22-0.76). Pessary use was associated with a significant reduction in the rate of birthweight <2500 g (P = .01). No significant differences were observed in composite neonatal morbidity outcome (8/136 [5.9%] vs 12/130 [9.1%]; relative risk, 0.64; 95% confidence interval, 0.27-1.50) or neonatal mortality (none) between the groups. No serious adverse effects associated with the use of a cervical pessary were observed.

CONCLUSION

The insertion of a cervical pessary was associated with a significant reduction in the SPB rate. We propose the use of a cervical pessary for preventing preterm birth in twin pregnancies of mothers with a short cervix.

Cervical pessary placement for prevention of preterm birth in unselected twin pregnancies: a randomized controlled trial

BACKGROUND

Preterm birth is the leading cause of neonatal death and handicap in survivors. Although twins are found in 1.5% of pregnancies they account for about 25% of preterm births. Randomized controlled trials in singleton pregnancies reported that the prophylactic use of progestogens, cervical cerclage and cervical pessary reduce significantly the rate of early preterm birth. In twin pregnancies, progestogens and cervical cerclage have been shown to be ineffective in reducing preterm birth.

OBJECTIVE

The objective of this study was to test the hypothesis that the insertion of a cervical pessary in twin pregnancies would reduce the rate of spontaneous early preterm birth.

STUDY DESIGN

This was a multicenter, randomized controlled trial in unselected twin pregnancies of cervical pessary placement from 20(+0)-24(+6) weeks' gestation until elective removal or delivery vs. expectant management. Primary outcome was spontaneous birth <34 weeks. Secondary outcomes included perinatal death and a composite of adverse neonatal outcomes (intraventricular haemorrhage, respiratory distress syndrome, retinopathy of prematurity or necrotizing enterocolitis) or need for neonatal therapy (ventilation, phototherapy, treatment for proven or suspected sepsis, or blood transfusion). Analysis was by intention to treat. This trial is registered in the ISRCTN registry, number 01096902.

RESULTS

A total of 1,180 (56.0%) of the 2,107 eligible women agreed to take part in the trial; 590 received cervical pessary and 590 had expectant management. Two of the former and one of the latter were lost to follow up. There were no significant differences between the pessary and control groups in rates of spontaneous birth <34 weeks (13.6% vs. 12.9%; relative risk 1.054, 95% confidence interval [CI] 0.787-1.413; p=0.722), perinatal death (2.5% vs. 2.7%; relative risk 0.908, 95% CI 0.553-1.491; p=0.702), adverse neonatal outcome (10.0 vs. 9.2%; relative risk 1.094, 95% CI 0.851-1.407; p=0.524) or neonatal therapy (17.9% vs. 17.2%; relative risk 1.040, 95% CI 0.871-1.242; p=0.701). A post hoc subgroup analysis of 214 women with short cervix (≤25 mm) showed no benefit from the insertion of a cervical pessary.

CONCLUSION

In women with twin pregnancy, routine treatment with cervical pessary does not reduce the rate of spontaneous early preterm birth.

Quantitative fetal fibronectin to predict spontaneous preterm birth: a review

Spontaneous preterm birth (sPTB) is the leading cause of neonatal morbidity and mortality globally. Accurate prediction of sPTB would enable targeting of interventions such as admission to hospital, antenatal corticosteroids, magnesium sulphate and in utero transfer as well as guiding prophylactic treatment (e.g., cerclage or progesterone). Measurement of fetal fibronectin concentration in the cervicovaginal fluid is a known predictor of sPTB. Traditionally a positive/negative test (defined by a threshold of 50 ng/ml), recent work has demonstrated improved prediction when used as a quantitative test, whereby the concentration of fetal fibronectin is measured by an automated bedside reader. This review examines the evidence surrounding the use of quantitative fetal fibronectin in asymptomatic women at high risk of sPTB, as well as those with symptoms of threatened sPTB.

Prevention of preterm birth with vaginal progesterone or 17-alpha-hydroxyprogesterone caproate: a critical examination of efficacy and safety

Progestogens are the first drugs to demonstrate reproducibly a reduction in the rate of early preterm birth. The efficacy and safety of progestogens are related to individual pharmacologic properties of each drug within this class of medication and characteristics of the population that is treated. The synthetic 17-hydroxyprogesterone caproate and natural progesterone have been studied with the use of a prophylactic strategy in women with a history of preterm birth and in women with a multiple gestation. Evidence from a single large comparative efficacy trial suggests that vaginal natural progesterone is superior to 17-hydroxyprogesterone caproate as a prophylactic treatment in women with a history of mid-trimester preterm birth. Progestogen therapy is indicated for women with this highest risk profile based on evidence from 2 trials. A therapeutic approach based on the identification of a sonographic short cervix has been studied in several phase III trials. Independent phase III trials and an individual patient metaanalysis suggest that vaginal progesterone is efficacious and safe in women with a singleton and a short cervix. Two trials that tested 17-hydroxyprogesterone caproate in women with a short cervix showed no benefit. No consistent benefit for the prophylactic or therapeutic use of progestogens has been demonstrated in larger trials of women whose pregnancies were complicated by a multiple gestation (twins or triplets), preterm labor, or preterm rupture of membranes. Unfortunately, several large randomized trials in multiple gestations have identified harm related to 17-hydroxyprogesterone caproate exposure, and the synthetic drug is contraindicated in this population. The current body of evidence is evaluated by the Grading of Recommendations Assessment, Development, and Evaluation guidelines to derive the strength of recommendation in each of these populations. A large confirmatory trial that is testing 17-hydroxyprogesterone caproate exposure in women with a singleton pregnancy and a history of preterm birth is near completion. Additional study of the efficacy and safety of progestogens is suggested in well-selected populations based on the presence of biomarkers.

[Cervical cerclage in Reunion island: Evaluation of physicians' practice patterns]

Cervical incompetency is one of the direct causes of neonatal morbidity and mortality; a unique and efficient treatment of which is cervical cerclage. The objective of this study was the evaluation of physicians' practice patterns concerning cerclage in Reunion Island, in order to reinforce the management and information of patients at risk. The indications and complications of cerclages effectuated in 2010 and 2011 were compared to the literature.

MATERIAL AND METHODS

In this retrospective study, all the medical records of cerclage realized in Reunion Island during two years were collected and analyzed, specifically data concerning patients' cerclage, the complications, and the outcome of the pregnancy.

RESULTS

We listed 200 cerclages, which were predominantly prophylactic cerclages (75.5%) and represented 0.71% of all births. A total of 71% of the indications of cerclage in Reunion Island did not take into account the recommendations of the literature. Analysis revealed the frequent use of prophylactic cerclage and subsequently reflected the insufficient use of therapeutic cerclage. In those cases, the rate of premature delivery was indeed lower (P=0.003), as well as the rate of chorioamniotitis (P=0.003).

CONCLUSION

Cerclage is an efficient treatment to extend the length of the pregnancy. Nevertheless, it is important to comply with the recommendations given by the literature, by spotting the patients at risk of premature delivery, and recommend cerclage only in case of real cervical incompetency, for the sake of improving their management and reducing the rate of complications.

The Effect of an Oxytocin Receptor Antagonist (Retosiban, GSK221149A) on the Response of Human Myometrial Explants to Prolonged Mechanical Stretch

Multiple pregnancy is a major cause of spontaneous preterm birth, which is related to uterine overdistention. The objective of this study was to determine whether an oxytocin receptor antagonist, retosiban (GSK221149A), inhibited the procontractile effect of stretch on human myometrium. Myometrial biopsies were obtained at term planned cesarean delivery (n = 12). Each biopsy specimen was dissected into 8 strips that were exposed in pairs to low or high stretch (0.6 or 2.4 g) in the presence of retosiban (1 μM) or vehicle (dimethylsulfoxide) for 24 hours. Subsequently, we analyzed the contractile responses to KCl and oxytocin in the absence of retosiban. We found that incubation under high stretch in vehicle alone increased the response of myometrial explants to both KCl (P = .007) and oxytocin (P = .01). However, there was no statistically significant effect of stretch when explants were incubated with retosiban (P = .3 and .2, respectively). Incubation with retosiban in low stretch had no statistically significant effect on the response to either KCl or oxytocin (P = .8 and >.9, respectively). Incubation with retosiban in high stretch resulted in a statistically significant reduction (median fold change, interquartile range, P) in the response to both KCl (0.74, 0.60-1.03, P = .046) and oxytocin (0.71, 0.53-0.91, P = .008). The greater the effect of stretch on explants from a given patient, the greater was the inhibitory effect of retosiban (r = -0.65, P = .02 for KCl and r= -0.73, P = .007 for oxytocin). These results suggest that retosiban prevented stretch-induced stimulation of human myometrial contractility. Retosiban treatment is a potential approach for preventing preterm birth in multiple pregnancy.

Incidence and risk factors for recurrent spontaneous preterm birth: A retrospective cohort study in Japan

AIM

The aim of this study was to assess the incidence and risk factors for recurrent spontaneous preterm birth (PTB) in Japan.

MATERIAL AND METHODS

A retrospective cohort study was conducted at five tertiary perinatal centers in Osaka, Japan from 2008 through 2012. Perinatal data were collected from medical records of women with a singleton gestation and a previous spontaneous PTB. Exclusion criteria were first-trimester spontaneous abortion, first antenatal visit beyond 14 weeks of gestation, and previous PTB with medical indications, placenta previa, abruptio placenta, multiple pregnancy, fetal anomaly, and antepartum fetal demise. The associations between recurrent spontaneous PTB and perinatal factors were evaluated by logistic regression analysis.

RESULTS

Of 547 women with a previous spontaneous PTB, 89 (16.3%) suffered a recurrent spontaneous PTB. The risk factors for recurrence included multiple previous spontaneous PTB (adjusted odds ratio [aOR]: 2.26; 95% confidence interval [CI]: 1.19-4.30; P = 0.013), no previous term birth (aOR: 2.08; 95%CI: 1.24-3.49; P = 0.005), and interpregnancy interval < 12 months (aOR: 2.13; 95%CI: 1.17-3.85; P = 0.013).

CONCLUSION

Approximately one in six women with a previous spontaneous PTB suffered a recurrent spontaneous PTB. Multiple previous spontaneous PTB, no previous term birth, and short interpregnancy interval were independent risk factors for recurrence.

Tocolytics used as adjunctive therapy at the time of cerclage placement: a systematic review

OBJECTIVE

To review the published literature on whether the use of empiric perioperative tocolytic medications could provide additional benefit when used in combination with cerclage.

STUDY DESIGN

Systematic review of published medical literature reporting the efficacy of empiric tocolytics used as a perioperative adjunct to vaginal cerclage in high-risk patients. A PubMed search without date criteria of various tocolytics and cerclage yielded 42 studies. Review articles were excluded, as were reports of abdominal cerclage, emergent cerclage, or cerclage for the purpose of delayed interval delivery in twin gestations.

RESULT

Only five publications on the topic of perioperative tocolytic use at the time of history or ultrasound-indicated vaginal cerclage placement were identified. These included zero clinical trials, three retrospective cohort studies, one case series and one case report. Only one cohort study compared cerclage with indomethacin and cerclage without indomethacin and suggested no difference between the groups. The other two published cohort studies had no referent group who received cerclage without tocolysis. One case series and one case report were also published reporting cerclage with empiric beta-mimetic and progesterone adjunctive therapy.

CONCLUSION

There is a paucity of published data on the topic of adjunctive perioperative tocolytics with cerclage. Adequately powered clinical trials on perioperative use of tocolysis with cerclage compared with a standard cerclage placement alone are needed to establish efficacy. Until adequately studied, this practice should be considered investigational.

[Progesterone and prevention of preterm birth]

The literature confirms the interest of progesterone for prevention of preterm delivery in specific indications for patients carrying a singleton pregnancy. In contrast, randomized trials have shown no benefit using progesterone in the prevention of prematurity in twins and even an adverse effect.

Prospective evaluation of a protocol for using transabdominal ultrasound to screen for short cervix

OBJECTIVE

We sought to evaluate a recently proposed protocol whereby transabdominal ultrasound of the cervix might be used as a prescreen to select women to undergo or to forgo measurement of cervical length via transvaginal ultrasound (CLvag).

STUDY DESIGN

This was a prospective cohort study. Measurements of cervical length via transabdominal ultrasound (CLabd) and CLvag were made in women with singleton pregnancy during routine obstetrical ultrasound examination at 18(0/7) to 23(6/7) weeks of gestation. The transabdominal screen was considered positive if CLabd was ≤36 mm with the maternal bladder full or ≤35 mm with the bladder empty, or adequate imaging of the cervix could not be obtained. Sensitivity, specificity, predictive values, and likelihood ratios of a positive screen to detect a short cervix (CLvag ≤25 mm) were calculated.

RESULTS

An interim analysis identified several technical problems with CLabd measurements, so the protocol was extensively revised. Under the revised protocol, 1580 women were included. Adequate views of the cervix were obtained via transabdominal imaging in 46% of subjects with the bladder empty and 56% with the bladder full. The correlation between CLabd and CLvag was poor (r = 0.38). Of the 17 patients with a short cervix, 15 had suboptimal transabdominal exams (screen positive) and 2 had CLabd ≤35 mm with bladder empty (screen positive). Sensitivity of the screen was 100% (95% confidence interval, 80.5-100%) but specificity was only 32.2% (95% confidence interval, 29.9-34.6%) and screen positive rate was 66.3%. Several technical problems and limitations of transabdominal imaging of the cervix are shown.

CONCLUSION

Using modern, high-resolution ultrasound equipment, we were unable to adequately image the cervix via transabdominal ultrasound in half the cases. Although we confirmed that a CLabd cutoff value of 35-36 mm is appropriate for detection of short cervix, the technique for measuring CLabd is fraught with technical problems. Practitioners must validate the technique in their own practice before adopting this or similar prescreening protocols. We decided not to adopt this protocol.

Omega-3 long chain polyunsaturated fatty acids to prevent preterm birth: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of omega-3 in reducing the incidence of preterm birth.

DATA SOURCES

Searches were performed in MEDLINE, OVID, Scopus, ClinicalTrials.gov, the PROSPERO International Prospective Register of Systematic Reviews, EMBASE, and the Cochrane Central Register of Controlled Trials with the use of a combination of keywords related to "fish oil," "pregnancy," and "omega-3."

METHODS OF STUDY SELECTION

We included all randomized controlled trials of asymptomatic women with singleton gestations who were randomized to prophylactic treatment with either omega-3 supplementation or control (either placebo or no treatment). Exclusion criteria included trials in women with multiple gestations, intrauterine growth restriction, gestational hypertension or preeclampsia at randomization, prior preterm birth, and trials with polyunsaturated fatty acids as control.

TABULATION, INTEGRATION, AND RESULTS

Nine randomized trials including 3,854 eligible women were identified. Women who received omega-3 had a similar rate of preterm birth before 37 weeks of gestation compared with women in the control group (7.7% compared with 9.1%, respectively; relative risk 0.90, 95% confidence interval [CI] 0.72-1.11). There were no significant differences in birth weight, neonatal intensive care unit admission, necrotizing enterocolitis, sepsis, or perinatal death in the omega-3 compared with control groups, respectively. There were no significant differences in the subgroup analyses, except for the rate of perinatal death, which was lower (0.3% compared with 1.2%; relative risk 0.27, 95% CI 0.09-0.80) in the women who received omega-3 before 21 weeks of gestation and in trials with low risk of bias (0.3% compared with 1.0%; relative risk 0.28, 95% CI 0.09-0.89) compared with women in the control group. However, in no randomized controlled trial was perinatal death the primary outcome.

CONCLUSION

Omega-3 supplementation during pregnancy does not reduce the incidence of preterm birth or improve neonatal outcome.

Efficacy of ultrasound-indicated cerclage in twin pregnancies

OBJECTIVE

We sought to compare the perinatal outcomes in twin pregnancies with short cervical length (CL) with ultrasound-indicated cerclage (UIC) vs no cerclage (control).

STUDY DESIGN

This was a retrospective cohort study of asymptomatic twin pregnancies with transvaginal ultrasound (TVU) CL ≤25 mm at 16-24 weeks from 1995 through 2012 at 4 separate institutions. Exclusion criteria were: genetic or major fetal anomaly, multifetal reduction >14 weeks, monochorionic-monoamniotic placentation, or medically indicated preterm birth (PTB). Primary outcome was spontaneous PTB (SPTB) <34 weeks. Secondary outcome was SPTB <28, <32, and <37 weeks. We also planned to evaluate primary and secondary outcome for the subgroup of twin pregnancies with CL ≤15 mm.

RESULTS

In all, 140 women with twin pregnancy and TVU-CL ≤25 mm were managed with either UIC (n = 57) or no cerclage (n = 83). Demographic characteristics were not significantly different except women who underwent UIC presented at an earlier gestational age (GA) at diagnosis of short CL. After adjusting for GA at presentation, there were no differences in GA at delivery or SPTB <28 weeks: 12 (21.2%) vs 20 (24.1%) (adjusted odds ratio [aOR], 0.3; 95% confidence interval [CI], 0.68-1.37), <32 weeks: 22 (38.6%) vs 36 (43.4%) aOR, 0.34; 95% CI, 0.1-1.13), or <34 weeks: 29 (50.9%) vs 53 (63.9%) (aOR, 0.37; 95% CI, 0.16-1.1). In the subgroup of women with CL ≤15 mm (32 with UIC and 39 controls) the interval between diagnosis to delivery was significantly prolonged by 12.5 ± 4.5 vs 8.8 ± 4.6 weeks (P < .001); SPTB <34 weeks was significantly decreased: 16 (50%) vs 31 (79.5%) (aOR, 0.51; 95% CI, 0.31-0.83) as was admission to neonatal intensive care unit: 38/58 (65.5%) vs 63/76 (82.9%) (aOR, 0.42; 95% CI, 0.24-0.81) when the UIC group was compared with the control group, respectively.

CONCLUSION

UIC in asymptomatic twin pregnancies with TVU-CL ≤25 mm was not associated with significant effects on perinatal outcomes compared to controls. However, in the planned subgroup analysis of asymptomatic twin pregnancies with TVU-CL ≤15 mm before 24 weeks, UIC was associated with a significant prolongation of pregnancy by almost 4 more weeks, significantly decreased SPTB <34 weeks by 49%, and admission to neonatal intensive care unit by 58% compared with controls.

A clinical opinion on how to manage the risk of preterm birth in twins based on literature review

Twin pregnancies are prone to preterm birth and consequent morbidity. There is an increasing evidence base concerning the prediction and prevention of preterm birth in singletons, including the reduction of morbidity with therapies such as magnesium sulphate and antenatal corticosteroids. However, the research in twins is less clear, partly due to fewer numbers being investigated, but also evidence is largely based on twins without a previous history. Prophylactic interventions such as cerclage, progesterone and vaginal pessaries are increasingly showing benefit in singleton pregnancies with a prior history and when the cervix is short. Cerclage in twins has not been adequately researched in women with previous preterm birth, and as with singletons should not be used on the basis of a short cervix alone. Vaginal progesterone does not work in twins, but its value in high-risk twins, with a prior history and short cervix is uncertain. The vaginal pessary may be valuable in the twin with a short cervix. Currently, it is reasonable to extrapolate some of the evidence from singletons to twins, e.g. with antenatal corticosteroids and magnesium sulphate. Cerclage, vaginal pessaries and progesterone should not be routinely used in twin pregnancies without an additional high-risk factor such as prior history of preterm birth or short cervix, until further evidence is obtained.

Obstetrical and neonatal outcomes of triplet births - spontaneous versus assisted reproductive technology conception

OBJECTIVE

To determine the average gestational age at birth and to compare obstetrical and neonatal outcomes of triplet births conceived spontaneously versus via assisted reproductive technology (ART).

METHODS

A retrospective chart review of triplet pregnancies that resulted in three live babies was conducted at Mount Sinai Hospital (Toronto, Canada) from January 2000 to June 2013.

RESULTS

A total of 230 women and 690 fetuses were identified. The mean gestational age at birth was 32.0 ± 3.8 weeks. Obstetrical outcomes included preterm premature rupture of the membranes in 29%, preterm labor in 26%, preeclampsia or HELLP syndrome in 19% and gestational diabetes in 10%. The mean birth weight of infants born after 24 weeks was 1655 ± 550 g and the rate of small for gestational age was 28%. The neonatal mortality rate prior to discharge was 7%. Aside from respiratory distress syndrome (30.6 versus 46.6%; p = 0.02), there were no differences in gestational age at birth, obstetrical or neonatal outcomes between spontaneous versus ART triplet conception. Monochorionicity carried a higher risk of small for gestational age, congenital anomalies and neonatal mortality compared to trichorionicity.

CONCLUSION

Rates of preterm birth and related complications remain high in triplet gestation. However, obstetrical and neonatal outcomes were similar for triplets conceived spontaneously versus via ART.

Recent advances in the prevention and management of preterm birth

The management of preterm birth has seen major transformations in the last few decades with increasing interest worldwide, due to the impact of preterm birth on neonatal morbidity and mortality. The prevention strategies currently available for asymptomatic women at risk of preterm birth include progesterone, cervical cerclage and cervical pessary. Each approach has varying effects depending on the patient's prior history of preterm birth, cervical length and the presence of multiple gestations. There is a shift in the focus of antenatal treatment, with the use of prenatal magnesium sulphate and corticosteroids, to reduce neonatal intensive care admissions and longer-term disabilities associated with preterm birth, consequently relieving emotional and economical burden. This article provides an update on the recent advances in prevention and management approaches available for women at risk of preterm birth.

Evaluation of Maternal-Fetal Outcomes After Emergency Vaginal Cerclage Performed With Shirodkar-McDonald Combined Modified Technique

Background

Several techniques of emergency vaginal cerclage have been proposed in case of unexpected and abrupt cervical incompetence (CI), in order to prolong the pregnancy as much as possible and to reduce the adverse maternal-fetal outcomes. The aim of our study was to evaluate the effectiveness of emergency cervical cerclage, performed with the combined modified Shirodkar-McDonald technique.

Methods

We selected 12 cases of emergency vaginal cerclage, performed between January 1, 2008 and June 30, 2013. The age of the patients was between 20 and 38 years (mean 29.0 ± standard deviation (SD) 5.69), parity between 0 and 2 (mean 0.7 ± SD 0.65), and gestational age at the time of admission ranged between 17 and 26 weeks (mean 21.0 ± SD 3.44). In all these cases, we used a combined modified Shirodkar-McDonald technique to perform the procedure.

Results

The neonatal survival rate was 83.3%. The cesarean section rate was 16.7%. The average pregnancy prolongation was 89.9 days, higher than that reported for other studies in the literature.

Conclusions

We can assume that the emergency vaginal cerclage performed with the combined modified Shirodkar-McDonald technique is the best option of surgical therapy for the treatment of unexpected and abrupt CI.

Is Early Treatment with a Cervical Pessary an Option in Patients with a History of Surgical Conisation and a Short Cervix?

Objective: Patients with a history of one or more conizations have an increased risk of spontaneous preterm birth (SPTB). The aim of this study was to investigate the outcome of pregnancies in patients with a history of conization and early treatment with a cervical pessary. Methods: In this pilot observational study we included 21 patients and evaluated the obstetric history, the interval between pessary placement and delivery, gestational age at delivery, the neonatal outcome and the number of days of maternal and neonatal admission. Results: Among the study group of 21 patients, 20 patients had a singleton and one had a dichorionic/diamniotic twin pregnancy. At insertion, the mean gestational age was 17 + 2 (10 + 5-24 + 0) weeks and the mean cervical length was 19 (4-36) mm. Six patients presented with funneling at insertion with a mean funneling width of 19.7 (10-38) mm and funneling length of 19.9 (10-37) mm. Five patients had already lost at least one child due to early spontaneous preterm birth and another five had at least one previous abortion, who have now delivered beyond 34 weeks. The mean gestational age at delivery was 38 (31 + 1-41 + 0) gestational weeks and the mean interval between insertion and delivery was 145 (87-182) days. Conclusion: Our findings suggest a beneficial effect of an early pessary placement for patients at high-risk for preterm birth due to conization.

Recurrent spontaneous miscarriage is still a challenging diagnostic and therapeutic quagmire

Recurrent spontaneous miscarriage (RSM), affecting 1-2% of women of reproductive age seeking pregnancy, has been a clinical quagmire and a formidable challenge for the treating physician. There are many areas of controversy in the definition, aetiology, investigations and treatment of RSM. This review will address the many factors involved in the aetiology of RSM which is multifactorial in many patients, with antiphospholipid syndrome (APS) being the most recognized aetiological factor. There is no identifiable cause in about 40-60% of these patients, in which case the condition is classified as idiopathic or unexplained RSM. The RSM investigations are extensive and should be undertaken in dedicated, specialized, well-equipped clinics/centres where services are provided by trained specialists. The challenges faced by the treating physician are even more overwhelming regarding the decision of what should be the most appropriate therapy offered to patients with RSM. Our review will cover the diverse modalities of therapy available including the role of preimplantation genetic testing using recent microarray technology, such as single nucleotide polymorphism and comparative genomic hybridization, as well as preimplantation genetic diagnosis; the greatest emphasis will be on the treatment of APS, and there will be important comments on the management of patients presenting with idiopathic RSM. The controversial areas of the role of natural killer cells in RSM, the varied modalities in the management of idiopathic RSM and the need for better-planned studies will be covered as well.

Clinical significance of amniotic fluid sludge in twin pregnancies with a short cervical length

OBJECTIVE

The objective of the study was to determine the clinical significance of amniotic fluid (AF) sludge in twin pregnancies with a short cervix.

STUDY DESIGN

We evaluated twin pregnancies with a short cervical length that had an ultrasound between 16 and 26 weeks (n = 78). Pregnancy outcomes in those with sludge (n = 27) and those without (n = 51) were compared. Outcome variables included gestational age at delivery, premature rupture of the membranes, chorioamnionitis, funisitis, composite neonatal morbidity, and perinatal death. For statistical analysis, the first-born (A) and second-born (B) twins were studied separately.

RESULTS

The prevalence of AF sludge was 34.6% (27 of 78). Pregnancies with sludge delivered earlier (27.2 ± 5.6 weeks vs 31.0 ± 4.05 weeks, P < .01) and had a higher rate of extreme prematurity (<26 weeks: 52.2% [12 of 23] vs 15.6% [5 of 32]; P < .01). Both twins had higher rates of histological chorioamnionitis (twin A, 50.0% [13 of 26] vs 12.8% [6 of 47]; P < .01; twin B, 42.3% [11 of 26] vs 13.3% [6 of 45]; P < .01) and neonatal death (twin A, 33.3% [9 of 27] vs 3.9% [2 of 51]; P < .01; twin B, 33.3% [9 of 27] vs 6.0% [3 of 50]; P = .01). Higher rates of funisitis (23.1% [6 of 26] vs 4.3% [2 of 47]; P = .02) and composite neonatal morbidity were observed for twin A only (66.7% [14 of 21] vs 37.5% [18 of 48]; P = .04).

CONCLUSION

The presence of AF sludge in twin pregnancies with a short cervix is a risk factor for extreme prematurity, histological chorioamnionitis, and perinatal death. Twin A had higher rates of funisitis and neonatal morbidity in the presence of AF sludge.

Removal versus retention of cerclage in preterm premature rupture of membranes: a randomized controlled trial

OBJECTIVE

The decision of whether to retain or remove a previously placed cervical cerclage in women who subsequently rupture fetal membranes in a premature gestation is controversial and all studies to date are retrospective. We performed a multicenter randomized controlled trial of removal vs retention of cerclage in these patients to determine whether leaving the cerclage in place prolonged gestation and/or increased the risk of maternal or fetal infection.

STUDY DESIGN

A prospective randomized multicenter trial of 27 hospitals was performed. Patients included were those with cerclage placement at ≤23 weeks 6 days in singleton or twin pregnancies, with subsequent spontaneous rupture of membranes between 22 weeks 0 days and 32 weeks 6 days. Patients were randomized to retention or removal of cerclage. Patients were then expectantly managed and delivered only for evidence of labor, chorioamnionitis, fetal distress, or other medical or obstetrical indications. Management after 34 weeks was at the clinician's discretion.

RESULTS

The initial sample size calculation determined that a total of 142 patients should be included but after a second interim analysis, futility calculations determined that the conditional power for showing statistical significance after randomizing 142 patients for the primary outcome of prolonging pregnancy was 22.8%. Thus the study was terminated after a total of 56 subjects were randomized with complete data available for analysis, 32 to removal and 24 to retention of cerclage. There was no statistical significance in primary outcome of prolonging pregnancy by 1 week comparing the 2 groups (removal 18/32, 56.3%; retention 11/24, 45.8%) P = .59; or chorioamnionitis (removal 8/32, 25.0%; retention 10/24, 41.7%) P = .25, respectively. There was no statistical difference in composite neonatal outcomes (removal 16/33, 50%; retention 17/30, 56%), fetal/neonatal death (removal 4/33, 12%; retention 5/30, 16%); or gestational age at delivery (removal mean 200 days; retention mean 198 days).

CONCLUSION

Statistically significant differences were not seen in prolongation of latency, infection, or composite neonatal outcomes. However, there was a numerical trend in the direction of less infectious morbidity, with immediate removal of cerclage. These findings may not have met statistical significance if the original sample size of 142 was obtained, however they provide valuable data suggesting that there may be no advantage to retaining a cerclage after preterm premature rupture of membranes and a possibility of increased infection with cerclage retention.

[Risk factors associated with spontaneous preterm deliveries before 30 weeks in Martinique F.W.I.: a case-control study]

OBJECTIVES

Early premature delivery is more prevalent in overseas territories than in continental France. Many differences are observed between pregnant women in France and in Martinique which may explain the higher preterm birth rate in the latter territory. The study compares prevalence of possible risk factors in preterm and term deliveries in Martinique.

PATIENTS AND METHODS

A retrospective study was conducted during two years (2010-2011). All deliveries before 30 weeks were included and several characteristics were compared with a group of term deliveries during the same period. All premature deliveries before 30 weeks were collected but only spontaneous ones were analysed.

RESULTS

Fifty deliveries before 30 weeks were recorded, among which 38 were spontaneous. Only a significantly higher prevalence of previous preterm delivery (OR=4.1 [1.3-13]) and twin pregnancies (OR=26.6 [3.19-219.6]) was found in the study group. Gram negative bacterial species were also more prevalent in vaginal sampling of preterm deliveries (OR=23.3 [2.7-204.6]).

CONCLUSION

Factors linked to prematurity before 30 weeks in Martinique are classical. Several features are different between pregnant women in France and in Martinique but do not appear as risk factors for prematurity in the latter territory.

Cervical stitch (cerclage) for preventing preterm birth in multiple pregnancy

BACKGROUND

Cervical cerclage is a surgical intervention involving placing a stitch around the uterine cervix. The suture material aims to prevent cervical shortening and opening, thereby reducing the risk of preterm birth. The effectiveness and safety of this procedure in multiple gestations remains controversial.

OBJECTIVES

To assess whether the use of a cervical cerclage in multiple gestations, either at high risk of pregnancy loss based on just the multiple gestation (history-indicated cerclage), the ultrasound findings of 'short cervix' (ultrasound-indicated cerclage), or the physical exam changes in the cervix (physical exam-indicated cerclage), improves obstetrical and perinatal outcomes. The primary outcomes assessed were perinatal deaths, serious neonatal morbidity, and perinatal deaths and serious neonatal morbidity.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of cervical cerclage in multiple pregnancies. Quasi-RCTs and RCTs using a cluster-randomised design were eligible for inclusion (but none were identified). Studies using a cross-over design and those presented only as abstracts were not eligible for inclusion.We included studies comparing cervical cerclage with no cervical cerclage in multiple pregnancies.Studies comparing cervical stitch versus any other preventative therapy (e.g. progesterone) in multiple pregnancies, and studies involving comparisons between different cerclage protocols (history-indicated versus ultrasound-indicated versus physical exam-indicated cerclage) were also eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias. Two review authors extracted data. Data were checked for accuracy.

MAIN RESULTS

We included five trials, which in total randomised 1577 women, encompassing both singleton and multiple gestations. After excluding singletons, the final analysis included 128 women, of which 122 women had twin gestations, and six women had triplet gestations. Two trials (n = 73 women) assessed history-indicated cerclage, while three trials (n = 55 women) assessed ultrasound-indicated cerclage. The five trials were judged to be of average to above average quality, with three of the trials at unclear risk regarding selection and detection biases.Concerning the primary outcomes, when outcomes for cerclage were pooled together for all indications and compared with no cerclage, there was no statistically significant differences in perinatal deaths (19.2% versus 9.5%; risk ratio (RR) 1.74, 95% confidence intervals (CI) 0.92 to 3.28, five trials, n = 262), serious neonatal morbidity (15.8% versus 13.6%; average RR 0.96, 95% CI 0.13 to 7.10, three trials, n = 116), or composite perinatal death and neonatal morbidity (40.4% versus 20.3%; average RR 1.54, 95% CI 0.58 to 4.11, three trials, n = 116).Among the secondary outcomes, there were no significant differences between the cerclage and the no cerclage groups. To name a few, there were no significant differences among the following: preterm birth less than 34 weeks (average RR 1.16, 95% CI 0.44 to 3.06, four trials, n = 83), preterm birth less than 35 weeks (average RR 1.11, 95% CI 0.58 to 2.14, four trials, n = 83), low birthweight less than 2500 g (average RR 1.10, 95% CI 0.82 to 1.48, four trials, n = 172), very low birthweight less than 1500 g (average RR 1.42, 95% CI 0.52 to 3.85, four trials, n = 172), and respiratory distress syndrome (average RR 1.70, 95% CI 0.15 to 18.77, three trials, n = 116). There were also no significant differences between the cerclage and no cerclage groups when examining caesarean section (elective and emergency) (RR 1.24, 95% CI 0.65 to 2.35, three trials, n = 77) and maternal side-effects (RR 3.92, 95% CI 0.17 to 88.67, one trial, n = 28).Examining the differences between prespecified subgroups, ultrasound-indicated cerclage was associated with an increased risk of low birthweight (average RR 1.39, 95% CI 1.06 to 1.83, Tau² = 0.01, I² = 15%, three trials, n = 98), very low birthweight (average RR 3.31, 95% CI 1.58 to 6.91, Tau² = 0, I² = 0%, three trials, n = 98), and respiratory distress syndrome (average RR 5.07, 95% CI 1.75 to 14.70, Tau² = 0, I² = 0%, three trials, n = 98). However, given the low number of trials, as well as substantial heterogeneity and subgroup differences, these data must be interpreted cautiously.No trials reported on long-term infant neurodevelopmental outcomes. There were no physical exam-indicated cerclages available for comparison among the studies included.

AUTHORS' CONCLUSIONS

This review is based on limited data from five small studies of average to above average quality. For multiple gestations, there is no evidence that cerclage is an effective intervention for preventing preterm births and reducing perinatal deaths or neonatal morbidity.

Prophylactic oral nifedipine to reduce preterm delivery: a randomized controlled trial in women at high risk

OBJECTIVE

To establish the efficacy of prophylactic nifedipine vs. placebo in reducing spontaneous preterm delivery in asymptomatic women at high risk for preterm delivery.

DESIGN

Prospective multicentric randomized double-blind study.

SETTING

Tertiary care centre, University Hospitals of Brescia and Torino, Italy.

POPULATION

Eighty-seven singleton pregnancies without uterine contractions and ultrasonographic cervical length of ≤25 mm at 24-32 weeks, at risk for preterm delivery, with longitudinal follow up in our Preterm Prevention Clinic.

METHODS

Selection was done on the basis of ultrasonographic cervical length; 43 women were randomized to receive placebo and 44 to receive nifedipine.

MAIN OUTCOME MEASURES

Primary end point: spontaneous preterm delivery <37 weeks in nifedipine vs. placebo.

SECONDARY OUTCOMES

delivery <32 weeks, maternal side effects, neonatal complications, admissions to the Neonatal Intensive Care Unit and randomization/delivery time in nifedipine vs. placebo.

RESULTS

There was no trend towards a lower risk of spontaneous preterm delivery, neither at <37 weeks of nifedipine vs. placebo (11.4% vs. 19.0%; p = 0.320), or <32 weeks (2.3% vs. 2.4%; p = 0.973). Nifedipine reduced spontaneous preterm delivery <37 weeks (p = 0.015) in the multiparous women by stratified analysis for parity. SECONDARY OUTCOMES between the groups did not differ except for a higher percentage of maternal side-effects in the nifedipine group (31.8%) vs. placebo (11.9%) (p < 0.05). Subgroup analysis showed a borderline (p = 0.047) lower percentage of spontaneous preterm delivery in women with a ultrasonographic cervical length of <20 mm in the nifedipine group.

CONCLUSIONS

Prophylactic nifedipine in asymptomatic women at high risk for preterm delivery had a positive effect on the rate of spontaneous preterm delivery <37 weeks in multiparous women.

Preterm birth prevention: how well are we really doing? A review of the latest literature

Preterm birth is a global concern resulting in prematurity which is the leading cause of newborn death and long-term squeal in the survivors. In this review, we will summarize the data available to this date in regard to the causes, available interventions, and contemporary research for future applications.

The effect of cerclage in twin gestations with short cervix: a Bayesian evaluation

OBJECTIVE

Bayesian inference allows the revision of prior clinical estimates of treatment effectiveness based on current data. We apply it to a published dataset evaluating the effect of cerclage upon preterm delivery in twin gestations with a short cervix.

STUDY DESIGN

Prior probability distributions for delivery <35 weeks gestation for the control group and the treatment (cerclage) group were constructed under assumptions ranging from treatment having no effect (prior A) to halving early deliveries (prior C). Likelihood functions were calculated based on a published meta-analysis. Posterior probability densities were derived from which risk ratios for early delivery were computed, with 95% credible intervals and the probability of cerclage benefit.

RESULTS

Median posterior risk ratios (95% credible intervals) for delivery <35 weeks with cerclage are 1.51 (1.02-2.33) for prior A and 1.11 (0.72-1.77) for prior C. The probability of cerclage benefit ranged from 2.1% for prior A to 31.4% for prior C. By comparison, the conventional risk ratio (95% confidence interval) for early delivery, based on the data alone, is 2.08 (1.18-3.69).

CONCLUSIONS

As might be anticipated, those with low expectation of cerclage benefit remain more convinced of the ineffectiveness (or harm) of the procedure than those with higher expectations.

ACOG Practice Bulletin No.142: Cerclage for the management of cervical insufficiency

The inability of the uterine cervix to retain a pregnancy in the second trimester is referred to as cervical insufficiency. Controversy exists in the medical literature pertaining to issues of pathophysiology, screening, diagnosis, and management of cervical insufficiency. The purpose of this document is to provide a review of current evidence of cervical insufficiency, including screening of asymptomatic at-risk women, and to offer guidelines on the use of cerclage for management. The diagnosis and management of other cervical issues during pregnancy, such as short cervical length, are discussed more in-depth in other publications of the American College of Obstetricians and Gynecologists.

Prediction of spontaneous preterm delivery in singleton pregnancies: where are we and where are we going? A review of literature

Prematurity is the chief cause of neonatal morbidity and mortality. The objective of this study is to review the different methods for predicting preterm delivery in asymptomatic pregnant women and in situations of threatened preterm delivery. A search of the PubMed/Medline database was carried out for the years 1980-2012. We included studies for predicting preterm birth in asymptomatic and symptomatic patients. Models for predicting preterm delivery based on maternal factors, cervical length and obstetric history in first trimester of pregnancy is a valuable avenue of research. Nevertheless, prediction accuracy still needs to be improved. In the second and third trimesters, routine digital vaginal examination is of no value in asymptomatic women. Echography of the cervix is not useful except in patients with a history of late miscarriage or preterm delivery in order to offer them a preventive treatment. In symptomatic women, the combination of digital vaginal examination, cervical echography and fibronectin gives the best predictive results. Electromyography of the uterus and elastography of the cervix are interesting avenues for future research. Identifying patients at risk of preterm delivery should be considered differently at each stage of pregnancy.

Rapid cervical phIGFBP-1 test in asymptomatic twin pregnancies: role in mid-pregnancy prediction of spontaneous preterm delivery

Objective This study aimed to assess the accuracy of a second-trimester rapid cervical phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1) test to predict spontaneous preterm delivery in asymptomatic twin pregnancies. Method During the second trimester, a rapid test to detect phIGFBP-1 in cervical secretions was performed on consecutive twin pregnancies between 2009 and 2011, to evaluate its predictive value for spontaneous preterm delivery at <28, <30, <32 and <34 weeks' gestation. Excluded were patients with cerclage, pessary or undergoing indicated preterm delivery. Results A total of 197 pregnancies fulfilled the study criteria and were tested at a median gestational age of 20.3 weeks (interquartile range: 20-20.6). Median gestational age at delivery was 36.4 weeks. Spontaneous preterm delivery at <34 weeks occurred in 21 (10.7%) cases, at <32 weeks in 9 (4.5%), at <30 weeks in 6 (3%) and at <28 weeks in 4 (2%). Seventeen patients (8.7%) were test positive: In this group, three patients delivered before 34 weeks' gestation, whereas none delivered at <32 weeks. The sensitivity, specificity, positive and negative predictive value of the test for spontaneous preterm delivery <34 weeks were 14% (95% confidence interval, 3-37%), 92% (86-95%), 17% (4-44%) and 90% (84-93%), respectively, with a positive and negative likelihood ratio of 1.79 (0.56-5.74) and 0.93 (0.78-1.10). Conclusions In the second trimester, rapid cervical phIGFBP-1 testing in asymptomatic twin pregnancies has a poor performance in predicting spontaneous preterm delivery.

Biocompatibility of a sonicated silk gel for cervical injection during pregnancy: in vivo and in vitro study

OBJECTIVE

To evaluate the biocompatibility of silk gel for cervical injection.

STUDY DESIGN

Silk gel was injected into the cervix of pregnant rats on day 13 (n = 11) and harvested at day 17. Histology of silk gel was compared with suture controls. Also, human cervical fibroblasts were cultured on silk gel and tissue culture plastic (TCP) in vitro. Cell viability, proliferation, metabolic activity, gene expression (COL1A1, COL3A1, and COX2), and release of proinflammatory mediators (interleukin [IL] 6 and IL-8) were evaluated.

RESULTS

In vivo, a mild foreign body response was seen surrounding the silk gel and suture controls. In vitro, cervical fibroblasts were viable, metabolically active, and proliferating at 72 hours. Release of IL-6 and IL-8 was similar on silk gel and TCP. Collagen and COX2 gene expression was similar or slightly decreased compared with TCP.

CONCLUSIONS

Silk gel was well tolerated in vivo and in vitro, which supports continuing efforts to develop silk gels as an alternative to cervical cerclage.

Use of cerclage in triplet pregnancies with an asymptomatic short cervix

OBJECTIVES

The purpose of this study was to compare the outcomes of triplet pregnancies in women with asymptomatic cervical shortening with and without a cervical cerclage.

METHODS

A retrospective review of all triplet pregnancies with biweekly serial cervical length surveillance was performed. Cervical shortening was defined as a cervical length of 2.5 cm or less before 24 weeks' gestation. Patients with cervical shortening managed with cerclage were compared to those managed expectantly. The primary outcome was the gestational age at delivery, with secondary outcomes including birth weight, neonatal intensive care unit length of stay, and composite neonatal outcome. Statistical significance was defined as P < .05.

RESULTS

Sixteen patients underwent cerclage placement versus 8 managed expectantly (control group). The median gestational ages at delivery were similar between the groups (cerclage, 31.3 weeks; interquartile range [IQR], 29.3-32.3 weeks; control, 29.8 weeks; IQR, 27.5-32.4 weeks; P = .71). The median birth weights were also similar between the groups (cerclage, 1283 g; IQR, 800-1626 g; control, 1109 g; IQR, 776-1500 g; P = .54). There was no significant difference in composite neonatal outcomes between the cerclage and control groups (P = .67).

CONCLUSIONS

In this limited case-control study, we found no benefit in terms of pregnancy prolongation or neonatal outcomes with cerclage placement for triplet gestations complicated by an asymptomatic short cervix.

Outcome of late second trimester emergency cerclage in patients with advanced cervical dilatation with bulging amniotic membranes: a report of six cases managed at the douala general hospital, cameroon

Purpose. To show the feasibility of emergency late second trimester cerclage with advanced cervical dilatation and bulging of amniotic membranes. Setting. Department of Obstetrics and Gynecology of the Douala General Hospital. Method. This is a retrospective study of case files of patients who underwent emergency late second trimester cerclage with advanced cervical dilatation, some with bulging of fetal membranes between June 2003 and June 2010. The modified Shirodkar technique was employed in all the cases. Results. Altogether, six patients (100%) underwent late second trimester cervical cerclage between 24 and 26 weeks of gestational age. Four cases (66.7%) carried on their pregnancies to term that resulted in healthy live-born babies all delivered vaginally. The other two cases (33.3%) presented with preterm premature rupture of fetal membranes (PPROM) which led us to undo the stitch with eventual delivery of live-born premature fetuses which died in the neonatal intensive care unit because of complications of prematurity and neonatal infection. Conclusion. In experienced hands and in the absence of other risk factors like infection, the success rates of this procedure are encouraging with improved prognosis. Finally, the modified Shirodkar technique yielded excellent results in our series.

Mid-trimester pregnancy loss

Mid-trimester pregnancy loss (MTL) occurs between 12 and 24 weeks' gestation. The true incidence of this pregnancy complication is unknown, because research into MTL in isolation is scarce, although the estimated incidence has been noted to be 2% to 3% of pregnancies. A comprehensive preconceptual screening protocol is recommended, because the cause for an MTL may be present in isolation or combined (dual pathology), and is often heterogeneous. Patients with a history of MTL are at an increased risk of future miscarriage and preterm delivery. This risk is increased further depending on the number of associative factors diagnosed.

Prevention of preterm delivery in twin pregnancy

The incidence of twin gestation has increased markedly over the past decades, mostly because of increased use of assisted reproductive technologies. Twin pregnancies are at increased risk of preterm delivery (i.e. birth before 37 weeks of gestation). Multiple gestations therefore account for 2-3% of all pregnancies but constitute at least 10% of cases of preterm delivery. Complications from preterm birth are not limited to the neonatal period, such as in retinopathy of prematurity, intraventricular haemorrhage, necrotising enterocolitis, respiratory disorder and sepsis; they can also constitute sequelae such as abnormal neurophysiological development in early childhood and underachievement in school. Several treatment modalities have been proposed in singleton high-risk pregnancies. The mechanism of initiating labour may, however, be different in singleton and twin gestations. Therefore, it is mandatory to evaluate the proposed treatments in randomised trials of multiple gestations. In this chapter, we describe the results of trials to prevent preterm delivery in twin pregnancies.