Single- versus double-layer closure of the caesarean (uterine) scar in the prevention of gynaecological symptoms in relation to niche development - the 2Close study: a multicentre randomised controlled trial.

BACKGROUND: Double-layer compared to single-layer closure of the uterus after a caesarean section (CS) leads to a thicker myometrial layer at the site of the CS scar, also called residual myometrium thickness (RMT). It possibly decreases the development of a niche, which is an interruption of the myometrium at the site of the uterine scar. Thin RMT and a niche are associated with gynaecological symptoms, obstetric complications in a subsequent pregnancy and delivery and possibly with subfertility. METHODS: Women undergoing a first CS regardless of the gestational age will be asked to participate in this multicentre, double blinded randomised controlled trial (RCT). They will be randomised to single-layer closure or double-layer closure of the uterine incision. Single-layer closure (control group) is performed with a continuous running, unlocked suture, with or without endometrial saving technique. Double-layer closure (intervention group) is performed with the first layer in a continuous unlocked suture including the endometrial layer and the second layer is also continuous unlocked and imbricates the first. The primary outcome is the reported number of days with postmenstrual spotting during one menstrual cycle nine months after CS. Secondary outcomes include surgical data, ultrasound evaluation at three months, menstrual pattern, dysmenorrhea, quality of life, and sexual function at nine months. Structured transvaginal ultrasound (TVUS) evaluation is performed to assess the uterine scar and if necessary saline infusion sonohysterography (SIS) or gel instillation sonohysterography (GIS) will be added to the examination. Women and ultrasound examiners will be blinded for allocation. Reproductive outcomes at three years follow-up including fertility, mode of delivery and complications in subsequent deliveries will be studied as well. Analyses will be performed by intention to treat. 2290 women have to be randomised to show a reduction of 15% in the mean number of spotting days. Additionally, a cost-effectiveness analysis will be performed from a societal perspective. DISCUSSION: This RCT will provide insight in the outcomes of single- compared to double-layer closure technique after CS, including postmenstrual spotting and subfertility in relation to niche development measured by ultrasound. TRIAL REGISTRATION: Dutch Trial Register ( NTR5480 ). Registered 29 October 2015.

Prenatal and postnatal findings in small-for-gestational-age fetuses without structural ultrasound anomalies at 18-24 weeks.

OBJECTIVE: To assess phenotypic and genotypic characteristics of small-for-gestational-age (SGA) fetuses without structural anomalies at 18-24 weeks' gestation. METHODS: This retrospective study included structurally normal singleton fetuses with an abdominal circumference ≤ 5th percentile on detailed ultrasound examination between 18 and 24 weeks' gestation. Cases were stratified according to the absence or presence of other abnormal ultrasound findings, such as abnormal amniotic fluid or soft markers. All patients were offered invasive prenatal testing with rapid aneuploidy detection by qualitative fluorescence polymerase chain reaction (QF-PCR) and, if normal, consecutive single nucleotide polymorphism (SNP) array was also offered. Detailed postnatal follow-up (≥ 5 months) was performed. In cases in which a syndromic phenotype became apparent within 5 months after birth and SNP array had not been performed prenatally, it was performed postnatally. RESULTS: A total of 211 pregnancies were eligible for inclusion. Of the 158 cases with isolated SGA on ultrasound, 36 opted for invasive prenatal testing. One case of trisomy 21 and one case of a submicroscopic abnormality (a susceptibility locus for neurodevelopmental disease) were detected. Postnatal follow-up showed a postnatal apparent syndromic phenotype in 10 cases. In one case this was due to trisomy 21 and the other nine (5.8%; 95% CI, 2.8-10.0%) cases had normal SNP array results. In 32/53 cases with SGA and associated ultrasound abnormalities, parents opted for invasive testing. One case of trisomy 21 and one of triploidy were found. In 11 cases a syndromic phenotype became apparent after birth. One was due to trisomy 21 and in one case a submicroscopic anomaly (a susceptibility locus) was found. The remaining syndromic cases (17.3%; 95% CI, 8.7-29.0%) had normal SNP array results. CONCLUSION: Testing for chromosomal anomalies should be offered in cases of SGA between 18 and 24 weeks' gestation. Whole chromosome anomalies occur in 1.3% (95% CI, 0.2-3.9%) of isolated SGA and 5.8% (95% CI, 1.5-14.0%) of associated SGA. In 0.6% (95% CI, 0.1-2.8%) and 1.9% (95% CI, 0.2-8.2%), respectively, SNP array detected a susceptibility locus for neurodevelopmental disease that would not be detected by karyotyping, QF-PCR or non-invasive prenatal testing. Therefore, and because the genetic causes of SGA are diverse, we suggest SNP array testing in cases of SGA. Thorough postnatal examination and follow-up of infants that presented with reduced fetal growth is important because chromosomally normal syndromic phenotypes occur frequently in SGA fetuses. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Transfusion policy after severe postpartum haemorrhage: a randomised non-inferiority trial.

OBJECTIVE: To assess the effect of red blood cell (RBC) transfusion on quality of life in acutely anaemic women after postpartum haemorrhage. DESIGN: Randomised non-inferiority trial. SETTING: Thirty-seven Dutch university and general hospitals. POPULATION: Women with acute anaemia (haemoglobin 4.8-7.9 g/dl [3.0-4.9 mmol/l] 12-24 hours postpartum) without severe anaemic symptoms or severe comorbidities. METHODS: Women were allocated to RBC transfusion or non-intervention. MAIN OUTCOME MEASURES: Primary outcome was physical fatigue 3 days postpartum (Multidimensional Fatigue Inventory, scale 4-20; 20 represents maximal fatigue). Non-inferiority was demonstrated if the physical fatigue difference between study arms was maximal 1.3. Secondary outcomes were health-related quality of life and physical complications. Health-related quality of life questionnaires were completed at five time-points until 6 weeks postpartum. RESULTS: In all, 521 women were randomised to non-intervention (n = 262) or RBC transfusion (n = 259). Mean physical fatigue score at day 3 postpartum, adjusted for baseline and mode of delivery, was 0.8 lower in the RBC transfusion arm (95% confidence interval: 0.1-1.5, P = 0.02) and at 1 week postpartum was 1.06 lower (95% confidence interval: 0.3-1.8, P = 0.01). A median of two RBC units was transfused in the RBC transfusion arm. In the non-intervention arm, 33 women received RBC transfusion, mainly because of anaemic symptoms. Physical complications were comparable. CONCLUSIONS: Statistically, non-inferiority could not be demonstrated as the confidence interval crossed the non-inferiority boundary. Nevertheless, with only a small difference in physical fatigue and no differences in secondary outcomes, implementation of restrictive management seems clinically justified.

Risk of developmental dysplasia of the hip in breech presentation: the effect of successful external cephalic version.

OBJECTIVE: To evaluate the effect of successful external cephalic version on the incidence of developmental dysplasia of the hip (DDH) requiring treatment in singleton breech presentation at term. DESIGN: Observational cohort study. SETTING: Three large teaching hospitals in the Netherlands. POPULATION: Women with a singleton breech presentation of 34 weeks of gestation or more, who underwent an external cephalic version attempt. METHODS: We made a comparison of the incidence of DDH between children born in breech presentation and children born in cephalic presentation after a successful external cephalic version. MAIN OUTCOME MEASURE: The incidence of DDH requiring either conservative treatment, with a harness, or surgical treatment. RESULTS: A total of 498 newborns were included in the study, of which 40 (8%) were diagnosed with DDH and 35 required treatment. Multivariate analysis showed that female gender (OR 2.79, 95% CI 1.23-6.35) and successful external cephalic version (OR 0.29, 95% CI 0.09-0.95) were independently associated with DDH. CONCLUSIONS: A successful external cephalic version is associated with a lower incidence of DDH, although a high percentage of children born after a successful external cephalic version still appear to have DDH. A larger cohort study is needed to establish the definite nature of this relationship. Until then, we recommend the same screening policy for infants born in cephalic position after a successful external cephalic version as for infants born in breech position.

Cost-effectiveness of induction of labour at term with a Foley catheter compared to vaginal prostaglandin E2 gel (PROBAAT trial).

OBJECTIVE: To assess the economic consequences of labour induction with Foley catheter compared to prostaglandin E2 gel. DESIGN: Economic evaluation alongside a randomised controlled trial. SETTING: Obstetric departments of one university and 11 teaching hospitals in the Netherlands. POPULATION: Women scheduled for labour induction with a singleton pregnancy in cephalic presentation at term, intact membranes and an unfavourable cervix; and without previous caesarean section. METHODS: Cost-effectiveness analysis from a hospital perspective. MAIN OUTCOME MEASURES: We estimated direct medical costs associated with healthcare utilisation from randomisation to 6 weeks postpartum. For caesarean section rate, and maternal and neonatal morbidity we calculated the incremental cost-effectiveness ratios, which represent the costs to prevent one of these adverse outcomes. RESULTS: Mean costs per woman in the Foley catheter group (n = 411) and in the prostaglandin E2 gel group (n = 408), were €3297 versus €3075, respectively, with an average difference of €222 (95% confidence interval -€157 to €633). In the Foley catheter group we observed higher costs due to longer labour ward occupation and less cost related to induction material and neonatal admissions. Foley catheter induction showed a comparable caesarean section rate compared with prostaglandin induction, therefore the incremental cost-effectiveness ratio was not informative. Foley induction resulted in fewer neonatal admissions (incremental cost-effectiveness ratio €2708) and asphyxia/postpartum haemorrhage (incremental cost-effectiveness ratios €5257) compared with prostaglandin induction. CONCLUSIONS: Foley catheter and prostaglandin E2 labour induction generate comparable costs.

Prediction of recurrence of hypertensive disorders of pregnancy between 34 and 37 weeks of gestation: a retrospective cohort study.

OBJECTIVE: To assess the recurrence risk of late-preterm hypertensive disease of pregnancy, and to determine whether potential risk factors are predictive. DESIGN: Retrospective cohort study. SETTING: Three secondary and three tertiary care hospitals in the Netherlands. POPULATION: We identified women with a hypertensive disorder in the index pregnancy and delivery at 34-37 weeks of gestation, between January 2000 and December 2002. METHODS: Data were extracted from medical files and women were approached for additional information on subsequent pregnancies. An adverse outcome was defined as the recurrence of a hypertensive disorder in the next subsequent pregnancy. MAIN OUTCOME MEASURES: Absolute risk of recurrence and a prediction model containing demographic and clinical factors predictive for adverse outcome. RESULTS: We identified 425 women who matched the criteria, of whom 351 could be contacted. Of these women, 189 (54%) had had a subsequent pregnancy. Hypertensive disorders recurred in 96 (51%, 95% CI 43-58%) women, of whom 17 (9%, 95% CI 5-14%) delivered again before 37 weeks of gestation. Chronic hypertension and maternal age were the strongest predictors for recurrence. Women undergoing recurrence had a nine-fold chance of developing chronic hypertension (37% versus 6%, OR 8.7, 95% CI 3.3-23). CONCLUSIONS: Women with hypertensive disorders and late-preterm delivery have a 50% chance of recurrence, but only a 9% chance of recurrence resulting in delivery before 37 weeks of gestation. Women with chronic hypertension are prone to develop recurrence, and women with a recurrence more often developed chronic hypertension.

Should cervical favourability play a role in the decision for labour induction in gestational hypertension or mild pre-eclampsia at term? An exploratory analysis of the HYPITAT trial.

OBJECTIVE: To examine whether cervical favourability (measured by cervical length and the Bishop score) should inform obstetricians' decision regarding labour induction for women with gestational hypertension or mild pre-eclampsia at term. DESIGN: A post hoc analysis of the Hypertension and Pre-eclampsia Intervention Trial At Term (HYPITAT). SETTING: Obstetric departments of six university and 32 teaching and district hospitals in the Netherlands. POPULATION: A total of 756 women diagnosed with gestational hypertension or pre-eclampsia between 36 + 0 and 41 + 0 weeks of gestation randomly allocated to induction of labour or expectant management. METHODS: Data were analysed using logistic regression modelling. MAIN OUTCOME MEASURES: The occurrence of a high-risk maternal situation defined as either maternal complications or progression to severe disease. Secondary outcomes were caesarean delivery and adverse neonatal outcomes. RESULTS: The superiority of labour induction in preventing high-risk situations in women with gestational hypertension or mild pre-eclampsia at term varied significantly according to cervical favourability. In women who were managed expectantly, the longer the cervix the higher the risk of developing maternal high-risk situations, whereas in women in whom labour was induced, cervical length was not associated with a higher probability of maternal high-risk situations (test of interaction P = 0.03). Similarly, the beneficial effect of labour induction on reducing the caesarean section rate was stronger in women with an unfavourable cervix. CONCLUSION: Against widely held opinion, our exploratory analysis showed that women with gestational hypertension or mild pre-eclampsia at term who have an unfavourable cervix benefited more from labour induction than other women. TRIAL REGISTRATION: The trial has been registered in the clinical trial register as ISRCTN08132825.

An economic analysis of induction of labour and expectant monitoring in women with gestational hypertension or pre-eclampsia at term (HYPITAT trial).

OBJECTIVE: To assess the economic consequences of labour induction compared with expectant monitoring in women with gestational hypertension or pre-eclampsia at term. DESIGN: An economic analysis alongside the Hypertension and Pre-eclampsia Intervention Trial At Term (HYPITAT). SETTING: Obstetric departments of six university and 32 teaching and district hospitals in the Netherlands. POPULATION: Women diagnosed with gestational hypertension or pre-eclampsia between 36(+0) and 41(+0) weeks of gestation, randomly allocated to either induction of labour or expectant monitoring. METHODS: A trial-based cost-effectiveness analysis was performed from a societal perspective during a 1-year time horizon. MAIN OUTCOME MEASURES: One-year costs were estimated and health outcomes were expressed as the prevalence of poor maternal outcome defined as either maternal complications or progression to severe disease. RESULTS: The average costs of induction of labour (n = 377) were €7077 versus €7908 for expectant monitoring (n = 379), with an average difference of -€831 (95% CI -€1561 to -€144). This 11% difference predominantly originated from the antepartum period: per woman costs were €1259 for induction versus €2700 for expectant monitoring. During delivery, more costs were generated following induction (€2190) compared with expectant monitoring (€1210). No substantial differences were found in the postpartum, follow-up and for non-medical costs. CONCLUSION: In women with gestational hypertension or mild pre-eclampsia at term, induction of labour is less costly than expectant monitoring because of differences in resource use in the antepartum period. As the trial already demonstrated that induction of labour results in less progression to severe disease without resulting in a higher caesarean section rate, both clinical and economic consequences are in favour of induction of labour in these women. TRIAL REGISTRATION: The trial has been registered in the clinical trial register as ISRCTN08132825.

Cornelia de lange syndrome: a recognizable fetal phenotype.

We describe a fetus with Cornelia de Lange syndrome diagnosed after termination of pregnancy at 21 weeks. Prenatally, growth retardation, diaphragmatic hernia, cystic hygroma and a right hand with only three rays were diagnosed by ultrasound in the second trimester of pregnancy. Postnatal magnetic resonance imaging confirmed the prenatal findings, and the presence of the typical dysmorphic features led to the diagnosis of Cornelia de Lange syndrome. The diagnosis was confirmed by the finding of a truncating mutation in the NIPBL gene. This case illustrates that the diagnosis Cornelia the Lange syndrome can be suspected prenatally in the second trimester, and can be diagnosed in fetuses after induction or newborns at birth as the typical phenotype is present early.

Feasibility and effectiveness of a lifestyle intervention after complicated pregnancies to improve risk factors for future cardiometabolic disease.

OBJECTIVES: To evaluate the feasibility and effectiveness of a postpartum lifestyle intervention after pregnancies complicated by preeclampsia, fetal growth restriction (FGR) and/or gestational diabetes mellitus (GDM) to improve maternal risk factors for future cardiometabolic disease. METHODS: Women following a complicated pregnancy were included six months postpartum in this specific pre-post controlled designed study. It has been conducted in one tertiary and three secondary care hospitals (intervention group) and one secondary care hospital (control group). The program consisted of a computer-tailored health education program combined with three individual counselling sessions during seven months. Primary outcome measures were the proportion of eligible women and weight change during the intervention. RESULTS: Two hundred and six women were willing to participate. The proportion of eligible women who complied with the intervention was 23%. Major barrier was lack of time. Adjusted weight change attributed to lifestyle intervention was -1.9 kg (95%-CI -4.3 to -0.3). Further changes were BMI (-0.9 kg/m2 (95%-CI -1.4 to -0.3)), waist-to-hip ratio (-0.04 cm/cm (95%-CI -0.06 to -0.03)), blood pressure medication use (19% (95%-CI 9% to 28%)), HOMA2-score (59 %S (95%-CI 18 to 99)) and total fat intake (-2.9 gr (95%-CI -4.6 to -1.2)). CONCLUSIONS: The results support feasibility and effectiveness of a lifestyle intervention after complicated pregnancies to improve maternal cardiometabolic risk factors. Further randomized controlled studies are needed with longer follow-up to evaluate durability. In the meantime, we suggest health care professionals to offer lifestyle interventions to women after complicated pregnancies.

[Results of pregnancy termination for foetal congenital or chromosomal disorders or intrauterine foetal death by oral mifepristone and/or intravaginal misoprostol; results of a retrospective study]. / Uitkomsten van zwangerschapsafbreking wegens foetale congenitale of chromosomale afwijkingen en bij intra-uteriene vruchtdood door middel van mifepriston oraal en/of misoprostol vaginaal; resultaten van een retrospectieve studie.

OBJECTIVE: To evaluate the method of mifepristone and misoprostol for pregnancy termination during the second trimester or for intrauterine foetal death during the second or third trimester. The primary outcome measure was time to delivery. Secondary outcomes included: complication registration, need for pain relief and side effects. DESIGN: Retrospective study of medical records. METHOD: Data were collected from patients in whom labour was induced due to intrauterine foetal death or in whom pregnancy was terminated due to a severe foetal congenital or chromosomal disorder between 1 September 2002 and 1 September 2005 in the Amphia Hospital, Breda, the Netherlands. Patients who experienced premature rupture of membranes, spontaneous abortion, or in whom labour was induced by insertion ofa intra-cervical balloon catheter were excluded. RESULTS: A total of 99 patients were included in the study. The mean age was 32 years in the intrauterine foetal-death group and 33 years in the pregnancy-termination group. The median gestational age was 21 weeks at the time of intrauterine foetal death and 19 weeks at the time of pregnancy termination. The median duration of treatment was 10 hours (range: 1-29) for intrauterine foetal death and 8 hours (range: 3-39) for pregnancy termination; the difference was statistically significant (p = 0.02). The mean duration of treatment did not differ statistically significant between these groups. The proportion of patients who delivered within 24 hours was 96% in the intrauterine foetal-death group and 92% in the pregnancy-termination group. Surgical removal of placenta or partially retained placenta was performed in 33% of all patients. There was no statistically significant difference in the median duration of treatment in nulliparous and multiparous patients; however, the risk of surgical removal of placenta or partially retained placenta was 5-fold greater in the nulliparous group (p < 0.05). No cases of uterine rupture were reported. Overall, 6% experienced severe haemorrhage, 18% had fever, 15% had nausea and 5% had vomiting. Epidural anaesthesia and intramuscular pethidine were administered in 28% and 24% of patients, respectively. CONCLUSION: The median duration of treatment was longer in patients in whom labour was induced due to intrauterine foetal death than in those in whom pregnancy was terminated for foetal disorders. The incidence of secondary outcomes such as complications, need for anaesthesia and side effects were comparable to numbers from earlier studies with mifepristone and misoprostol.

Effect of levothyroxine on live birth rate in euthyroid women with recurrent miscarriage and TPO antibodies (T4-LIFE study).

BACKGROUND: Thyroid peroxidase antibodies (TPO-Ab) in euthyroid women are associated with recurrent miscarriage (RM) and other pregnancy complications such as preterm birth. It is unclear if treatment with levothyroxine improves pregnancy outcome. AIM: The aim of this study is to determine the effect of levothyroxine administration on live birth rate in euthyroid TPO-Ab positive women with recurrent miscarriage. METHODS/DESIGN: We will perform a multicenter, placebo controlled randomized trial in euthyroid women with recurrent miscarriage and TPO-Ab. Recurrent miscarriage is defined as two or more miscarriages before the 20th week of gestation. The primary outcome is live birth, defined as the birth of a living fetus beyond 24weeks of gestation. Secondary outcomes are ongoing pregnancy at 12weeks, miscarriage, preterm birth, (serious) adverse events, time to pregnancy and survival at 28days of neonatal life. The analysis will be performed according to the intention to treat principle. We need to randomize 240 women (120 per group) to demonstrate an improvement in live birth rate from 55% in the placebo group to 75% in the levothyroxine treatment group. This trial is a registered trial (NTR 3364, March 2012). Here we discuss the rationale and design of the T4-LIFE study, an international multicenter randomized, double blind placebo controlled, clinical trial aimed to assess the effectiveness of levothyroxine in women with recurrent miscarriage and TPO-Ab.

Hemodynamic and metabolic effects after nifedipine and ritodrine tocolysis.

OBJECTIVES: The purpose of this study is to compare the hemodynamic and metabolic changes after ritodrine and nifedipine tocolysis. METHODS: For an open randomized study, patients with preterm labor (N=185) were allocated to groups to receive ritodrine intravenously (N=90) or nifedipine orally (N=95). RESULTS: The mean diastolic blood pressure was significantly lower in the ritodrine group 24 h (65+/-12 vs. 70+/-8, P=0.001) and 48 h (65+/-12 vs. 71+/-8, P=0.004) after starting tocolysis compared with the nifedipine group. Mean maternal heart rate was significantly higher in the ritodrine group 24 h (105+/-17 vs. 86+/-13, P<0.0001) and 48 h (100+/-21 vs. 85+/-12, P<0.0001) after starting tocolysis compared with the nifedipine group. Mean fasting glucose levels were higher (6.68+/-2.53 vs. 4.93+/-1.23, P=0.0016), while mean potassium levels were lower (3.52+/-0.84 vs. 3.81+/-0.45, P=0.04) in the ritodrine group 48 h after starting tocolysis compared with the nifedipine group. CONCLUSIONS: Use of nifedipine for preterm labor is associated with a lower incidence of adverse hemodynamic and metabolic changes compared with ritodrine after 24 and 48 h of tocolysis. In our opinion nifedipine is the preferred drug of choice for the treatment of preterm labor.

[Nifedipine first choice in management of threatening preterm labor]. / Nifedipine eerste keus bij de behandeling van dreigende vroeggeboorte.

Preterm birth is the most important cause of perinatal mortality in Europe and North America. Tocolytic agents named beta 2-sympathicomimetics postpone delivery for 24-48 hours, but do not reduce perinatal mortality or morbidity. Calcium antagonists, in particular nifedipine, are more effective tocolytic agents than beta 2-sympathicomimetics in terms of delaying delivery. Meta-analyses have found that calcium antagonists statistically significantly reduced perinatal morbidity and that the number of maternal side effects was statistically significantly lower compared with beta 2-sympathicomimetics. Nifedipine also has the benefit of oral administration, in contrast with beta 2-sympathicomimetics which are administered intravenously. Nifedipine is therefore the first choice in the management of threatening preterm labour.

Long-term follow up of children exposed in utero to nifedipine or ritodrine for the management of preterm labour.

OBJECTIVE: To compare the long-term psychosocial and motor effects on children exposed in utero to nifedipine or ritodrine for the management of preterm labour. DESIGN: Randomised controlled trial. SETTING: Multicentre study in two university and one primary hospital in the Netherlands. POPULATION: In the original trial, 185 women were randomised to either nifedipine (n = 95) or ritodrine (n = 90). Of the 185 liveborn children, 171 survived (92%), and of these 102 (61%) were followed up at age 9-12 years. METHODS: Age-specific questionnaires were administered to the parent and teacher. Additional data were obtained from medical records. MAIN OUTCOME MEASURES: Questionnaires were used to assess the child's behavioural-emotional problems, quality of life (QoL), motor functioning, parenting distress and the child's education. RESULTS: Of the 171 eligible families, 102 (61%) agreed to participate and completed the questionnaires. Response was equal in the ritodrine group (n = 54 of 83 surviving children, 65%) compared with the nifedipine group (n= 48 of 88 surviving children, 55%). After controlling for differing perinatal characteristics at birth, no significant differences between the groups were detected with respect to long-term behaviour-emotional outcome, QoL, education, motor functioning or parenting distress. Psychosocial outcome was slightly better in the nifedipine group. CONCLUSIONS: The results do not support any differential postnatal effect of the tocolytic agents ritodrine or nifedipine on the child's long-term psychosocial and motor functioning. The slightly better outcome of children randomised in the nifedipine group is most likely due to more favourable perinatal outcomes in this group. These results merit further investigation in a larger group of survivors.