Characteristics associated with antenatally unidentified small-for-gestational-age fetuses: prospective cohort study nested within DESiGN randomized controlled trial

OBJECTIVE

To identify the clinical characteristics and patterns of ultrasound use amongst pregnancies with an antenatally unidentified small-for-gestational-age (SGA) fetus, compared with those in which SGA is identified, to understand how to design interventions that improve antenatal SGA identification.

METHODS

This was a prospective cohort study of singleton, non-anomalous SGA (birth weight < 10th centile) neonates born after 24 + 0 gestational weeks at 13 UK sites, recruited for the baseline period and control arm of the DESiGN trial. Pregnancy with antenatally unidentified SGA was defined if there was no scan or if the final scan showed estimated fetal weight (EFW) at the 10th centile or above. Identified SGA was defined if EFW was below the 10th centile at the last scan. Maternal and fetal sociodemographic and clinical characteristics were studied for associations with unidentified SGA using unadjusted and adjusted logistic regression models. Ultrasound parameters (gestational age at first growth scan, number and frequency of ultrasound scans) were described, stratified by presence of indication for serial ultrasound. Associations of unidentified SGA with absolute centile and percentage weight difference between the last scan and birth were also studied on unadjusted and adjusted logistic regression, according to time between the last scan and birth.

RESULTS

Of the 15 784 SGA babies included, SGA was not identified antenatally in 78.7% of cases. Of pregnancies with unidentified SGA, 47.1% had no recorded growth scan. Amongst 9410 pregnancies with complete data on key maternal comorbidities and antenatal complications, the risk of unidentified SGA was lower for women with any indication for serial scans (adjusted odds ratio (aOR), 0.56 (95% CI, 0.49-0.64)), for Asian compared with white women (aOR, 0.80 (95% CI, 0.69-0.93)) and for those with non-cephalic presentation at birth (aOR, 0.58 (95% CI, 0.46-0.73)). The risk of unidentified SGA was highest among women with a body mass index (BMI) of 25.0-29.9 kg/m2 (aOR, 1.15 (95% CI, 1.01-1.32)) and lowest in those with underweight BMI (aOR, 0.61 (95% CI, 0.48-0.76)) compared to women with BMI of 18.5-24.9 kg/m2 . Compared to women with identified SGA, those with unidentified SGA had fetuses of higher SGA birth-weight centile (adjusted odds for unidentified SGA increased by 1.21 (95% CI, 1.18-1.23) per one-centile increase between the 0th and 10th centiles). Duration between the last scan and birth increased with advancing gestation in pregnancies with unidentified SGA. SGA babies born within a week of the last growth scan had a mean difference between EFW and birth-weight centiles of 19.5 (SD, 13.8) centiles for the unidentified-SGA group and 0.2 (SD, 3.3) centiles for the identified-SGA group (adjusted mean difference between groups, 19.0 (95% CI, 17.8-20.1) centiles).

CONCLUSIONS

Unidentified SGA was more common amongst women without an indication for serial ultrasound, and in those with cephalic presentation at birth, BMI of 25.0-29.9 kg/m2 and less severe SGA. Ultrasound EFW was overestimated in women with unidentified SGA. This demonstrates the importance of improving the accuracy of SGA screening strategies in low-risk populations and continuing performance of ultrasound scans for term pregnancies. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Improving antenatal detection of small-for-gestational-age fetus: economic evaluation of Growth Assessment Protocol

OBJECTIVE

To determine whether the Growth Assessment Protocol (GAP), as implemented in the DESiGN trial, is cost-effective in terms of antenatal detection of small-for-gestational-age (SGA) neonate, when compared with standard care.

METHODS

This was an incremental cost-effectiveness analysis undertaken from the perspective of a UK National Health Service hospital provider. Thirteen maternity units from England, UK, were recruited to the DESiGN (DEtection of Small for GestatioNal age fetus) trial, a cluster randomized controlled trial. Singleton, non-anomalous pregnancies which delivered after 24 + 0 gestational weeks between November 2015 and February 2019 were analyzed. Probabilistic decision modeling using clinical trial data was undertaken. The main outcomes of the study were the expected incremental cost, the additional number of SGA neonates identified antenatally and the incremental cost-effectiveness ratio (ICER) (cost per additional SGA neonate identified) of implementing GAP. Secondary analysis focused on the ICER per infant quality-adjusted life year (QALY) gained.

RESULTS

The expected incremental cost (including hospital care and implementation costs) of GAP over standard care was £34 559 per 1000 births, with a 68% probability that implementation of GAP would be associated with increased costs to sustain program delivery. GAP identified an additional 1.77 SGA neonates per 1000 births (55% probability of it being more clinically effective). The ICER for GAP was £19 525 per additional SGA neonate identified, with a 44% probability that GAP would both increase cost and identify more SGA neonates compared with standard care. The probability of GAP being the dominant clinical strategy was low (11%). The expected incremental cost per infant QALY gained ranged from £68 242 to £545 940, depending on assumptions regarding the QALY value of detection of SGA.

CONCLUSION

The economic case for replacing standard care with GAP is weak based on the analysis reported in our study. However, this conclusion should be viewed taking into account that cost-effectiveness analyses are always limited by the assumptions made. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Randomized controlled pilot trial with ion-exchange water softeners to prevent eczema (SOFTER trial)

BACKGROUND

Observational studies suggest an increased risk of eczema in children living in hard versus soft water areas, and there is, therefore, an interest in knowing whether softening water may prevent eczema. We evaluated the feasibility of a parallel-group assessor-blinded pilot randomized controlled trial to test whether installing a domestic ion-exchange water softener before birth in hard water areas reduces the risk of eczema in infants with a family history of atopy.

METHODS

Pregnant women living in hard water areas (>250 mg/L calcium carbonate) in and around London UK, were randomized 1:1 antenatally to either have an ion-exchange water softener installed in their home or not (ie to continue to receive usual domestic hard water). Infants were assessed at birth and followed up for 6 months. The main end-points were around feasibility, the primary end-point being the proportion of eligible families screened who were willing and able to be randomized. Clinical end-points were evaluated including frequency of parent-reported doctor-diagnosed eczema and visible eczema on skin examination. Descriptive analyses were conducted, and no statistical testing was performed as this was a pilot study.

RESULTS

One hundred and forty-nine families screened were eligible antenatally and 28% (41/149) could not have a water softener installed due to technical reasons or lack of landlord approval. Eighty of 149 (54%) were randomized, the primary end-point. Two participants withdrew immediately after randomization, leaving 39 participants in each arm (78 total). Attrition was 15% (12/78) by 6 months postpartum. All respondents (n = 69) to the study acceptability questionnaire reported that the study was acceptable. Fifty-six of 708 (7.9%) water samples in the water softener arm were above the hard water threshold of 20 mg/L CaCO₃ . At 6 months of age 27/67 infants (40%) developed visible eczema, 12/36 (33%) vs. 15/31 (48%) in the water softener and control groups, respectively, difference -15% (95% CI -38, 8.3%), with most assessments (≥96%) remaining blinded. Similarly, a lower proportion of infants in the water softener arm had parent-reported, doctor-diagnosed eczema by 6 months compared to the control arm, 6/17 (35%) versus 9/19 (47%), difference -12% (95% CI -44, 20%).

CONCLUSION

A randomized controlled trial of water softeners for the prevention of atopic eczema in high-risk infants is feasible and acceptable.

POPPIE: protocol for a randomised controlled pilot trial of continuity of midwifery care for women at increased risk of preterm birth

Background

High rates of preterm births remain a UK public health concern. Preterm birth is a major determinant of adverse infant and longer-term outcomes, including survival, quality of life, psychosocial effects on the family and health care costs. We aim to test whether a model of care combining continuity of midwife care with rapid referral to a specialist obstetric clinic throughout pregnancy, intrapartum and the postpartum period is feasible and improves experience and outcomes for women at increased risk of preterm birth.

Methods

This pilot, hybrid, type 2 randomised controlled implementation trial will recruit 350 pregnant women at increased risk of preterm birth to a midwifery continuity of care intervention or standard care. The intervention will be provided from recruitment (antenatal), labour, birth and the postnatal period, in hospital and community settings and in collaboration with specialist obstetric clinic care, when required. Standard care will be the current maternity care provision by NHS midwives and obstetricians at the study site. Participants will be followed up until 6–8 weeks postpartum. The composite primary outcome is the appropriate initiation of any specified interventions related to the prevention and/or management of preterm labour and birth. Secondary outcomes are related to: recruitment and attrition rates; implementation; acceptability to women, health care professionals and stakeholders; health in pregnancy and other complications; intrapartum outcomes; maternal and neonatal postnatal outcomes; psycho-social health; quality of care; women’s experiences and health economic analysis. The trial has 80% power to detect a 15% increase in the rate of appropriate interventions (40 to 55%). The analysis will be by ‘intention to treat’ analysis.

Discussion

Little is known about the underlying reasons why and how models of midwifery continuity of care are associated with fewer preterm births, better maternal and infant outcomes and more positive experiences; nor how these models of care can be implemented successfully in the health services. This will be the first study to provide direct evidence regarding the effectiveness, implementation and evaluation of a midwifery continuity of care model and rapid access to specialist obstetric services for women at increased risk of preterm birth.

Trial registration

ISRCTN37733900. Retrospectively registered on 21 August 2017.

Reporting errors, incidence and risk factors for postpartum haemorrhage and progression to severe PPH: a prospective observational study

OBJECTIVE

To quantify reporting errors, measure incidence of postpartum haemorrhage (PPH) and define risk factors for PPH (≥500 ml) and progression to severe PPH (≥1500 ml).

DESIGN

Prospective observational study.

SETTING

Two UK maternity services.

POPULATION

Women giving birth between 1 August 2008 and 31 July 2009 (n = 10 213).

METHODS

Weighted sampling with sequential adjustment by multivariate analysis.

MAIN OUTCOME MEASURES

Incidence and risk factors for PPH and progression to severe PPH.

RESULTS

Errors in transcribing blood volume were frequent (14%) with evidence of threshold preference and avoidance. The incidences of PPH ≥500, ≥1500 and ≥2500 ml were 33.7% (95% CI 31.2-36.2), 3.9% (95% CI 3.3-4.6) and 0.8% (95% CI 0.6-1.0). New independent risk factors predicting PPH ≥ 500 ml included Black African ethnicity (adjusted odds ratio [aOR] 1.77, 95% CI 1.31-2.39) and assisted conception (aOR 2.93, 95% CI 1.30-6.59). Modelling demonstrated how prepregnancy- and pregnancy-acquired factors may be mediated through intrapartum events, including caesarean section, elective (aOR 24.4, 95% CI 5.53-108.00) or emergency (aOR 40.5, 95% CI 16.30-101.00), and retained placenta (aOR 21.3, 95% CI 8.31-54.7). New risk factors were identified for progression to severe PPH, including index of multiple deprivation (education, skills and training) (aOR 1.75, 95% CI 1.11-2.74), multiparity without caesarean section (aOR 1.65, 95% CI 1.20-2.28) and administration of steroids for fetal reasons (aOR 2.00, 95% CI 1.24-3.22).

CONCLUSIONS

Sequential, interacting, traditional and new risk factors explain the highest rates of PPH and severe PPH reported to date.

Prospective cohort study investigating the reliability of the AmnioSense method for detection of spontaneous rupture of membranes

OBJECTIVE

This study investigated the reliability, sensitivity and specificity of a commercially available absorbent pad, AmnioSense, compared with speculum examination for detection of spontaneous ruptured membranes (SRM).

DESIGN

Prospective cohort study.

SETTING

Antenatal Day Unit (ADU) of a UK inner-city teaching hospital.

POPULATION

Women attending the ADU with a history of suspected ruptured membranes between 18 and 42 weeks of gestation.

METHODS

Eligible women were asked to use the absorbent pad in accordance with the manufacturer's instructions. A midwife recorded the result. A second midwife performed a speculum examination according to unit protocol. Results were entered onto a password-protected study-specific database. Both midwives were blind to the other test result.

MAIN OUTCOME MEASURES

Comparability between the index test (AmnioSense) and reference standard (speculum).

RESULTS

A total of 157 women were recruited and results were analysed in 139 cases. Median gestational age at recruitment was 37(+2) weeks. The prevalence of SRM was 42% (59/139) with AmnioSense giving a sensitivity of 98% (58/59) and specificity of 65% (52/80).

CONCLUSIONS

Thirty-eight percent (53/139 women) with SRM would have been correctly identified as having intact membranes without the need for a speculum examination. Twenty-five percent of AmnioSense false-positive results were associated with positive high vaginal swab results (7/28). These data suggest that a negative AmnioSense result can provide reassurance of intact membranes. Use of the AmnioSense test before considering speculum examination could reduce the number of speculum examinations undertaken, with benefit to women and concomitant health resource savings.

Physical map of a conditionally dispensable chromosome in Nectria haematococca mating population VI and location of chromosome breakpoints

Certain isolates of the plant pathogenic fungus Nectria haematococca mating population (MP) VI contain a 1.6-Mb conditionally dispensable (CD) chromosome carrying the phytoalexin detoxification genes MAK1 and PDA6-1. This chromosome is structurally unstable during sexual reproduction. As a first step in our analysis of the mechanisms underlying this chromosomal instability, hybridization between overlapping cosmid clones was used to construct a map of the MAK1 PDA6-1 chromosome. The map consists of 33 probes that are linked by 199 cosmid clones. The polymerase chain reaction and Southern analysis of N. haematococca MP VI DNA digested with infrequently cutting restriction enzymes were used to close gaps and order the hybridization-derived contigs. Hybridization to a probe extended from telomeric repeats was used to anchor the ends of the map to the actual chromosome ends. The resulting map is estimated to cover 95% of the MAK1 PDA6-1 chromosome and is composed of two ordered contigs. Thirty-eight percent of the clones in the minimal map are known to contain repeated DNA sequences. Three dispersed repeats were cloned during map construction; each is present in five to seven copies on the chromosome. The cosmid clones representing the map were probed with deleted forms of the CD chromosome and the results were integrated into the map. This allowed the identification of chromosome breakpoints and deletions.

Partial MAT-2 gene structure and the influence of temperature on mating success in Gibberella circinata

Genetic analysis of Gibberella circinata, the causative agent of pitch canker disease of pines, historically has been thwarted by a low frequency of mating success in the laboratory. We describe two findings that should facilitate genetic analysis of this fungus and related species. First, we determined that previously described degenerate primers could be used to amplify a portion of the MAT-2 mating type gene from G. circinata. This led to the cloning and sequencing of a fragment of the MAT-2 gene, which in turn made it possible to distinguish between G. circinata isolates of opposite mating types. Second, we discovered that of the 18 G. circinata field isolates in our collection, the 1 female fertile isolate expressed its fertility at 15 and 20 degrees C but not at 25 degrees C, the temperature used for crossing many Gibberella species. It is evident, therefore, that when sexual reproduction in other closely related species is initially being investigated, the crosses should be established at a variety of temperatures. Once we learned that female fertility in this G. circinata isolate was expressed at 20 degrees C, a high frequency of mating success was achieved.