Sean K. Seeho

Villous explant culture using early gestation tissue from ongoing pregnancies with known normal outcomes: the effect of oxygen on trophoblast outgrowth and migration

BACKGROUND Early placental and embryo development occur in a physiologically low oxygen environment, with a rise in oxygen tension within the placenta towards the end of the first trimester. Oxygen is implicated in the regulation of trophoblast differentiation and invasion. This study examined the effects of oxygen tension on extravillous trophoblast outgrowth and migration from normal pregnancies free of significant pathology. METHODS Early gestation villous tissue (11-14 weeks gestation), obtained by chorionic villus sampling, was cultured in 3 or 20% oxygen. Maternal and fetal outcomes were ascertained for all samples. The frequency and amount of trophoblast outgrowth and migration from villi were measured for up to 192 h. RESULTS Significantly fewer explants produced outgrowths in 3% compared with 20% oxygen. The number of sites of trophoblast outgrowth and the extent of migration were also significantly less in 3% compared with 20% oxygen. In vitro hypoxia/reoxygenation further reduced trophoblast growth compared with 3% oxygen alone. HLA-G expression in extravillous trophoblasts was not affected by oxygen tension, with HLA-G positive extravillous trophoblasts being universally Ki67 negative. CONCLUSION Human placental villi and extravillous trophoblasts in the late first trimester of pregnancy are sensitive to oxygen tension, with low oxygen inhibiting extravillous trophoblast outgrowth and migration.

Differential Placental Gene Expression in Term Pregnancies Affected by Fetal Growth Restriction and Macrosomia

Introduction: Extremes of fetal growth are associated with increased perinatal mortality and morbidity and a higher prevalence of cardiovascular disease, obesity and diabetes in later life. We aimed to identify changes in placental gene expression in pregnancies with evidence of growth dysfunction and candidate genes that may be used to identify abnormal patterns of growth prior to delivery. Methods: Growth-restricted (n = 4), macrosomic (n = 6) and normal term (n = 5) placentas were selected from a banked series (n = 200) collected immediately after caesarean section. RNA was extracted prior to microarray analysis using Affymetrix HG-U219 arrays to determine variation in gene expression. Genes of interest were confirmed using qRT-PCR. Results: 338 genes in the growth-restricted and 41 genes in the macrosomic group were identified to be significantly dysregulated (>2-fold change; p < 0.05). CPXM2 and CLDN1 were upregulated and TXNDC5 and LRP2 downregulated in fetal growth restriction. In macrosomia, PHLDB2 and CLDN1 were upregulated and LEP and GCH1 were downregulated. Discussion: Dysfunctional growth is associated with differential placental gene expression and affects genes with a whole spectrum of developmental and cellular functions. Better elucidation of these pathways may allow the development of biomarkers to identify growth abnormalities and effective prenatal intervention.

Venous thromboembolism prophylaxis during and following caesarean section: a survey of clinical practice

Caesarean section (CS) is a significant risk factor for venous thromboembolism; however, the optimal method of thromboprophylaxis around the time of CS is unknown.

Association Between Glycemic Variability, HbA1c, and Large-for-Gestational-Age Neonates in Women With Type 1 Diabetes

Fetal exposure to hyperglycemia is a major determinant of large-for-gestational-age (LGA; birth weight >90th centile for gender) neonates (1), yet targets for glycemic control beyond the first trimester in type 1 diabetes (T1D) pregnancy remain controversial. As HbA1c represents a summary measure of glycemic control, it might not adequately reflect acute glucose fluctuations or glycemic variability (GV) that contributes to excess fetal growth. Moreover, neonates born to women who attain HbA1c <6% (42 mmol/mol) in the third trimester of pregnancy have an LGA prevalence of 25% (2), with associated adverse perinatal outcomes (3). In contrast to HbA1c, continuous glucose monitoring (CGM) allows precise observation of GV. Several studies have demonstrated an association between higher GV and increased birth weight (1,4,5). The capability of GV compared with HbA1c to identify women likely to have LGA neonates is, however, unclear. We evaluated the association between various measures of GV, HbA1c, and LGA neonates in T1D pregnancy. Twenty-one pregnant women with T1D were recruited over a 2-year period, and measurements of HbA1c and GV (EasyGV, University …

Outcomes of twin pregnancies complicated by gestational diabetes: a meta-analysis of observational studies

Objective:Gestational diabetes mellitus (GDM) in singleton pregnancy is associated with large for gestational age neonates and adverse perinatal outcomes; however, the impact of GDM in twin pregnancy is unclear. Thus, the aim of this study is to assess the perinatal outcomes of twin pregnancies complicated by GDM by performing a meta-analysis of observational studies.Study Design:Studies investigating GDM in twin pregnancy were identified through an online search of three databases: Medline, Embase and Web of Science. Selection criteria comprised full paper observational studies (retrospective or prospective) published in English that examined GDM in twin pregnancy compared with non-GDM twin pregnancy and reported on birth weight and/or adverse perinatal outcomes. Random-effects models with inverse-variance weighting were used to calculate standardized mean differences and unadjusted odds ratios. Sensitivity analyses were carried out to determine the impact of possible maternal confounders (body mass index and age) and GDM diagnostic criteria on perinatal outcomes.Results:Thirteen observational studies were included. GDM twins were born at the same gestation as non-GDM twins, with marginally lower birth weight. There was no difference in the incidence of large or small for gestational age neonates. Although there was no correlation between GDM in twin pregnancy and respiratory distress, neonatal hypoglycemic or low Apgar score, GDM twins had a higher rate of neonatal intensive care unit admission (OR 1.49; 95% confidence interval: 1.10, 2.02; P<0.01).Conclusion:Identification and subsequent treatment of GDM in twin pregnancy demonstrates a similar risk of adverse perinatal outcomes compared with non-GDM twin pregnancies.

Methods of classification for women undergoing induction of labour: a systematic review and novel classification system

A lack of reproducible methods for classifying women having an induction of labour (IOL) has led to controversies regarding IOL and related maternal and perinatal health outcomes.

Term breech delivery: Is recommending vaginal birth a breach of best practice?

The Term Breech Trial (TBT) showed that a policy of planned caesarean delivery is substantially safer than a policy of planned vaginal birth for the term fetus in the breech presentation.1 Following its publication, much of the world changed practice.2 However, the clear demonstration of reduced harm to the fetus with caesarean section was not enough to end debate on how best to deliver the term breech fetus. The TBT was followed by criticism from some authors, and even a call for its recommendations to be withdrawn.3–5 Notwithstanding any doubts over the TBT results, there is much epidemiological evidence,6–11 including from an Australian obstetric population,12 to support the implementation of a policy of planned caesarean section for breech delivery. We present data that show the totality of evidence supports the relative safety of caesarean section over vaginal birth for the term breech infant and contend that it is no longer justifiable for obstetricians to claim, that in their hands, vaginal birth is not associated with increased fetal risk. The TBT, published in The Lancet in October 2000, found the primary composite outcome of perinatal mortality or serious neonatal morbidity was considerably lower with planned caesarean section than for planned vaginal birth (1.6% vs 5.0%; relative risk (RR) 0.33 (95% confidence interval (CI) 0.19–0.56); P < 0.0001), with no difference in maternal mortality or serious morbidity.1 Caesarean section remained a significantly safer method of delivery for the fetus compared with vaginal breech birth irrespective of clinician experience, parity, presence of labour or ruptured membranes, or estimated size or weight of the fetus, among other factors. The difference in the primary outcome between groups was already evident at an interim analysis, such that the data monitoring committee recommended cessation of trial recruitment. The TBT is not without its limitations; however, it is highquality evidence. It was a large, international, independently randomised controlled trial with outcome data for 2083/2088 women. The trial was carefully designed and conducted, and had clear predefined outcomes. Why, then, in the face of such seemingly convincing results has the uptake of caesarean section for the term breech not been universal? The reason is that some clinicians continue to cast doubt on the TBT results and generalisability.3–5 Although the TBT showed a clear improvement in perinatal outcomes, 2year followup of 923 children found no difference in the risk of death or neurodevelopmental delay (RR 1.09; 95% CI 0.52–2.30).13 The lack of difference between the caesarean and vaginal birth groups was likely due to the study being underpowered; however, a recent Australian study suggests that longterm child health, development and educational achievement are not affected by mode of birth.14 The longterm outcome data may lessen the importance of the shortterm morbidity findings of the TBT, but they do not diminish the importance of the more serious finding of increased perinatal death following vaginal birth. Advocates of vaginal breech birth might also claim that the TBT results are not generalisable; that in their practice vaginal delivery is as safe as caesarean section. Indeed, they might even point to findings from the PREMODA study,15 a prospective observational study conducted in France and Belgium following publication of the TBT, which examined the outcomes of 8105 singleton term breech fetuses. The PREMODA study reported very different results from the TBT with regards to perinatal mortality and serious neonatal morbidity, with no difference between planned vaginal birth (1.60%; 95% CI 1.14–2.17) and caesarean delivery (1.45%; 95% CI 1.16–1.81). However, the difference between the two studies may have been due to the way in which women were allocated

Thromboprophylaxis after caesarean: when even the ‘experts’ disagree

Venous thromboembolism (VTE) is a leading cause of maternal morbidity and mortality in developed countries. The early postpartum period is a time of particular risk, with rates of VTE further increased following operative delivery. Prevention of pregnancy-associated VTE is of considerable importance and interest; however, there have been no randomised studies of sufficient size to inform the relative benefits and harms of management strategies. In the absence of evidence, there has been recourse to expert opinion, with numerous professional bodies having either produced or endorsed guidelines aimed at reducing VTE during pregnancy and in the puerperium. These guidelines commonly use risk stratification as a basis for thromboprophylaxis recommendations. In this issue of BJOG, Palmerola et al. illustrate the divergence in expert opinion by reporting the markedly discrepant rates of birthing women that would qualify for pharmacological thromboprophylaxis following caesarean section should the recommendations from the American Congress of Obstetricians and Gynecologists (ACOG), the Royal College of Obstetricians and Gynaecologists (RCOG), and the American College of Chest Physicians (Chest) be applied. In a cohort of 293 women attending a tertiary hospital in the USA, 85.0, 34.8, and 1.0% of patients would fulfil RCOG, Chest, and ACOG criteria for low-molecular-weight heparin (LMWH), respectively. Approximately half of the women were obese (47.1%) or aged ≥35 years (50.9%), and one-third had a caesarean section in labour (33.8%). Although caution needs to be exercised before extrapolating these results to the general obstetric population, they highlight the large difference between guidelines in risk factors considered important for VTE and eligibility criteria for thromboprophylaxis after caesarean section. Note that if the most recent RCOG guidelines published in 2015 were applied to the cohort, the proportion of women receiving LMWH would be even greater. When it comes to the prevention of thrombosis after caesarean section, guideline recommendations have brought about as much controversy as they have consensus. Although well intentioned, recommendations are based not on incontrovertible evidence, but largely on expert opinion, observational studies, and extrapolation from non-obstetric populations. Indeed, an acknowledgement of this low grade of evidence can be found in each of the guidelines. It is disappointing that the evidence on which to base indications for heparin use and duration of therapy after caesarean section are limited. A recent Cochrane systematic review comparing heparin thromboprophylaxis with placebo following caesarean section, based on only 840 women, found no difference in thromboembolic events (Bain et al. Cochrane Database Syst Rev 2014;2: CD001689). Proponents will cite the fall in maternal deaths in the UK between 2003–05 and 2006–08, following the publication and implementation of the 2004 RCOG guidelines, as evidence to support the use of risk score-based guidelines (CMACE BJOG 2011;118:S1–S203). In New South Wales, Australia, however, the rate of pulmonary embolism after caesarean section for the period 2001–06 fell prior to the adoption of risk-factor scores to routinely guide heparin use after caesarean section, despite marked increases in risk factors such as maternal age and body mass index (BMI) (Morris et al. J Thromb Haemost 2010;8:998– 1003). Interestingly, the most recent UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2009–12 found that there has not been a further reduction in the maternal death rate from thromboembolism between 2006–08 and 2010–12 (Knight et al. MBRRACE-UK 2014). The findings highlight the pressing need for large-scale and appropriately designed clinical studies to establish the optimal method of thromboprophylaxis for the large number of women having caesarean section. The experts who produce these guidelines should unite to lead the design and execution of such studies.

Referral of patients for pre‐implantation genetic diagnosis: A survey of obstetricians

Pre‐implantation genetic diagnosis (PGD) is a molecular diagnostic technique in which embryos are tested for specific genetic abnormalities to enable the selection of those unaffected by the condition. Previous Australian evidence suggested that women who are not informed about PGD by their obstetrician feel disempowered about not being given this option.

Change in smoking status during two consecutive pregnancies: A population-based cohort study

To investigate changes in tobacco smoking in two consecutive pregnancies and factors associated with the change.