Balancing key stakeholder priorities and ethical principles to design a trial comparing intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy: FERN qualitative study.

OBJECTIVES: As part of the FERN feasibility study, this qualitative research aimed to explore parents' and clinicians' views on the acceptability, feasibility and design of a randomised controlled trial (RCT) of active intervention versus expectant management in monochorionic (MC) diamniotic twin pregnancies with early-onset (prior to 24 weeks) selective fetal growth restriction (sFGR). Interventions could include laser treatment or selective termination which could lead to the death or serious disability of one or both twins. DESIGN: Qualitative semi-structured interviews with parents and clinicians. Data were analysed using reflexive thematic analysis and considered against the Principles of Biomedical Ethics. PARTICIPANTS AND SETTING: We interviewed 19 UK parents experiencing (six mothers, two partners) or had recently experienced (eight mothers, three partners) early-onset sFGR in MC twin pregnancy and 14 specialist clinicians from the UK and Europe. RESULTS: Participants viewed the proposed RCT as 'ethically murky' because they believed that the management of sFGR in MC twin pregnancy should be individualised according to the type and severity of sFGR. Clinicians prioritised the gestational age, size, decrease in growth velocity, access to the placental vessels and acceptability of intervention for parents. Discussions and decision-making about selective termination appeared to cause long-term harm (maleficence). The most important outcome for parents and clinicians was 'live birth'. For clinicians, this was the live birth of at least one twin. For parents, this meant the live birth of both twins, even if this meant that their babies had neurodevelopmental impairment or disabilities. CONCLUSIONS: All three pregnancy management approaches for sFGR in MC twin pregnancy carry risks and benefits, and the ultimate goal for parents is to receive individualised care to achieve the best possible outcome for both twins. An RCT was not acceptable to parents or clinicians or seen as ethically appropriate. Alternative study designs should be considered to answer this important research question.

FERN: is it possible to conduct a randomised controlled trial of intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy - protocol for a prospective multicentre mixed-methods feasibility study.

INTRODUCTION: Selective fetal growth restriction (sFGR) in monochorionic twin pregnancy, defined as an estimated fetal weight (EFW) of one twin <10th centile and EFW discordance ≥25%, is associated with stillbirth and neurodisability for both twins. The condition poses unique management difficulties: on the one hand, continuation of the pregnancy carries a risk of death of the smaller twin, with a high risk of co-twin demise (40%) or co-twin neurological sequelae (30%). On the other, early delivery to prevent the death of the smaller twin may expose the larger twin to prematurity, with the associated risks of long-term physical, emotional and financial costs from neurodisability, such as cerebral palsy.When there is severe and early sFGR, before viability, delivery is not an option. In this scenario, there are currently three main management options: (1) expectant management, (2) selective termination of the smaller twin and (3) placental laser photocoagulation of interconnecting vessels. These management options have never been investigated in a randomised controlled trial (RCT). The best management option is unknown, and there are many challenges for a potential RCT. These include the rarity of the condition resulting in a small number of eligible pregnancies, uncertainty about whether pregnant women will agree to participate in such a trial and whether they will agree to be randomised to expectant management or active fetal intervention, and the challenges of robust and long-term outcome measures. Therefore, the main objective of the FERN study is to assess the feasibility of conducting an RCT of active intervention vs expectant management in monochorionic twin pregnancies with early-onset (prior to 24 weeks) sFGR. METHODS AND ANALYSIS: The FERN study is a prospective mixed-methods feasibility study. The primary objective is to recommend whether an RCT of intervention vs expectant management of sFGR in monochorionic twin pregnancy is feasible by exploring women's preference, clinician's preference, current practice and equipoise and numbers of cases. To achieve this, we propose three distinct work packages (WPs). WP1: A Prospective UK Multicentre Study, WP2A: a Qualitative Study Exploring Parents' and Clinicians' Views and WP3: a Consensus Development to Determine Feasibility of a Trial. Eligible pregnancies will be recruited to WP1 and WP2, which will run concurrently. The results of these two WPs will be used in WP3 to develop consensus on a future definitive study. The duration of the study will be 53 months, composed of 10 months of setup, 39 months of recruitment, 42 months of data collection, and 5 months of data analysis, report writing and recommendations. The pragmatic sample size for WP1 is 100 monochorionic twin pregnancies with sFGR. For WP2, interviews will be conducted until data saturation and sample variance are achieved, that is, when no new major themes are being discovered. Based on previous similar pilot studies, this is anticipated to be approximately 15-25 interviews in both the parent and clinician groups. Engagement of at least 50 UK clinicians is planned for WP3. ETHICS AND DISSEMINATION: This study has received ethical approval from the Health Research Authority (HRA) South West-Cornwall and Plymouth Ethics Committee (REC reference 20/SW/0156, IRAS ID 286337). All participating sites will undergo site-specific approvals for assessment of capacity and capability by the HRA. The results of this study will be published in peer-reviewed journals and presented at national and international conferences. The results from the FERN project will be used to inform future studies. TRIAL REGISTRATION NUMBER: This study is included in the ISRCTN Registry (ISRCTN16879394) and the NIHR Central Portfolio Management System (CPMS), CRN: Reproductive Health and Childbirth Specialty (UKCRN reference 47201).

El embarazo gemelar monocorial desde la perspectiva de la teoría de la complejidad / Monochorionic twin pregnancy from the perspective of the theory of complexity

En la práctica, es muy frecuente asociar las gestaciones gemelares monocoriales (MC) con embarazos complejos o complicados, utilizando ambos términos en forma intercambiable. Sin embargo, no lo son; el dinamismo es protagonista en los sistemas complejos, pero no en los complicados. Para entender a la embarazada con una gestación MC como un sistema complejo, primero se desarrollarán las características principales de los embarazos MC; su placenta es una de las principales responsables de los problemas. Luego se analizará el embarazo MC desde la complejidad, identificando las características del sistema y sus complicaciones como propiedades emergentes.

In practice, it is very common to associate monochorionic (MC) twin pregnancies with complex or complicated pregnancies, using both terms interchangeably. However, these are not synonyms; dynamism is the protagonist in complex systems, but not in complicated ones. In order to understand a MC pregnancy as a complex system, it is necessary to first look into its main characteristics. The placenta is one of the main sources of problems. Then, the MC pregnancy has to be analyzed from the perspective of complexity, identifying the system characteristics and its complications as emergent properties.

The association between maternal obesity and fetomaternal outcomes in twin pregnancies.

The prevalence of overweight and obese people worldwide has dramatically increased in the last decades and is yet to peak. At the same time and partly due to obesity and associated assisted reproduction, twinning rates showed a clear rise in the last years. Adverse fetomaternal outcomes are known to occur in singleton and twin pregnancies in overweight and obese women. However, the impact of the obesity levels as defined by the World Health Organization on the outcomes of twin pregnancies has not been thoroughly studied. Therefore, the purpose of this study is to examine how maternal overweight, and the level of obesity affect fetomaternal outcomes in twin pregnancies, hypothesizing a higher likelihood for adverse outcomes with overweight and each obesity level. This is a retrospective cohort study with 2,349 twin pregnancies that delivered at the Buergerhospital Frankfurt, Germany between 2005 and 2020. The mothers were divided into exposure groups depending on their pre-gestational body mass index; these were normal weight (reference group), overweight and obesity levels I, II, and III. A multivariate logistic regression analysis was performed to assess the influence of overweight and obesity on gestational diabetes mellitus, preeclampsia, postpartum hemorrhage, intrauterine fetal death, and a five-minutes Apgar score below seven. The adjusted odds ratio for gestational diabetes compared to normal weight mothers were 1.47, 2.79, 4.05, and 6.40 for overweight and obesity levels I, II and III respectively (p = 0.015 for overweight and p < 0.001 for each obesity level). Maternal BMI had a significant association with the risk of preeclampsia (OR 1.04, p = 0.028). Overweight and obesity did not affect the odds of postpartum hemorrhage, fetal demise, or a low Apgar score. While maternal overweight and obesity did not influence the fetal outcomes in twin pregnancies, they significantly increased the risk of gestational diabetes and preeclampsia, and that risk is incremental with increasing level of obesity.

Association of genomic prediction for twin pregnancies with the incidence of double ovulation in primiparous dairy cows.

Twin pregnancies compromise the health and well-being of dairy cattle. A recent genomic prediction model for twin pregnancies has been developed based on twin calving or abortion. However, the incidence of double ovulation is significantly higher than that of twin births. This study aimed to evaluate whether genomic prediction values for twin pregnancies are associated with the incidence of double ovulation in primiparous dairy cows. Factors influencing the double ovulation rate were analysed using binary logistic regression on 676 cows: 475 (70.3%) inseminated at spontaneous estrus and 201 following one of two different estrus synchronization protocols for fixed-time artificial insemination (FTAI). The odds ratio for double ovulations was 0.92 (p = .002) per unit increase in prediction value and 2 (p = .01) for cows subjected to an FTAI protocol. Our findings suggest that genomic prediction values for twin pregnancies can effectively identify the risk of double ovulation at the herd level.

Maternal Circulating Vitamin D Level, Targeted Supplementation, and Perinatal Outcomes in Twin Pregnancy.

BACKGROUND: Vitamin D deficiency is associated with several obstetric complications in singleton pregnancy. The aim of this study was to assess whether vitamin D levels affect the outcomes of twin pregnancy and if targeted supplementation can improve perinatal outcomes. METHODS: The serum vitamin D levels of 143 women with twin pregnancies were measured during their first trimester. Those with insufficient (10-30 ng/mL; IL group) or severely deficient (<10 ng/mL, DL group) vitamin D levels were supplemented. In the third trimester, vitamin D levels were reassessed. Perinatal outcomes of the IL and DL groups were compared with those of patients with sufficient levels (>30 ng/mL, SL group) since the beginning of pregnancy. RESULTS: Women in the IL and DL groups had a higher incidence of hypertensive disorders of pregnancy (HDP) compared to the SL group (24.8% and 27.8% vs. 12.5%, p = 0.045): OR = 1.58 for the IL group and 1.94 for the DL group compared to the SL group. In patients whose vitamin D levels were restored after supplementation, HDP incidence was lower than in patients who remained in the IL or DL groups (23.4% vs. 27.3%) but higher than those who were always in the SL group (12.5%). CONCLUSIONS: Insufficient or severely deficient levels of vitamin D in the first trimester are associated with an increased risk of HDP in twin pregnancy. The beneficial effect of targeted vitamin D supplementation in reducing HDP seems limited.

Conservative Management of a Monochorionic Twin Pregnancy with an Intrauterine Fetal Death at 20-21 Weeks and Successful Term Delivery of the Second Twin.

BACKGROUND One of the obstetric complications of twin pregnancy was the intrauterine death of one fetus. The death that occurs in the first trimester usually leads to fewer complications than the death in the second and third trimester. In the second and third trimesters, single fetal death of twin pregnancy was reported to increase the death, preterm birth, and neurological injury of the surviving co-twin. Although rare, it might trigger a coagulation defect in the mother as well. Neurological morbidities were also more common in monochorionic twins than in dichorionic gestation. Thus, a consideration of pregnancy termination might persist. CASE REPORT We present a case of a primigravida with a monochorionic twin pregnancy whose intrauterine death of one fetus at 20-21 weeks of gestation. We managed this patient with pregnancy continuation under close monitoring more than 12 weeks until she delivered the surviving one at term. The outcome of the surviving baby was normal condition and appropriate weight, no fetal morbidity, and no maternal morbidity related to coagulation disorder in the mother. CONCLUSIONS Conservative management under close monitoring until term in monochorionic twin pregnancy with single fetal death could be the best option to obtain a favorable outcome. We recommend conservative management with close surveillance monitoring using non-stress tests after 32 weeks, biweekly ultrasound, and at least of one maternal coagulation profile test.

The influence of previous preterm birth with singleton pregnancy on the risk of recurrence in subsequent twin pregnancy: a meta-analysis.

BACKGROUND: Preterm birth is a significant obstetrical concern around the globe. With this study, we aimed to determine whether a prior singleton pregnancy preterm birth increases the likelihood of preterm birth in subsequent twin pregnancies. We designed his systematic review to provide valuable information for pregnant women and obstetricians during counselling and for individuals involved in the planning of preventive strategies. METHODS: We comprehensively searched the PubMed, Embase and Scopus databases to identify relevant studies published until October 2023 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We applied a random-effects meta-analysis to the data gathered from the selected studies. RESULTS: Among the 460 initially identified studies, only eight met the eligibility criteria. The analysis of incidence revealed an event rate of 9.5% (95% CI, 4.4-19.5%) for a history of preterm singleton birth in the cohort of women with subsequent twin pregnancies. Subgroup analyses focused on the risk of preterm twin births (<37 weeks, <34 weeks and <32 weeks) in women with prior preterm singleton births. Our results revealed a significantly elevated risk of subsequent preterm twin births associated with prior preterm singleton births at <37 weeks (OR, 2.94; 95% CI, 1.99-4.33; p < .001), <34 weeks (OR, 1.89; 95% CI, 1.67-2.14; p < .001) and <32 weeks (OR, 2.51; 95% CI, 1.58-3.99; p < .001), without heterogeneity in the included studies. CONCLUSIONS: Our systematic analysis indicates a consistent and statistically significant association between a history of preterm singleton births and preterm twin births at various gestational ages. These findings underscore the importance of the obstetric history during assessments to predict the risk of preterm births in twin pregnancies. Clinicians should monitor pregnancies with a history of preterm singleton births, as targeted interventions and improved prenatal care can mitigate the risk of preterm birth during twin pregnancies.

Preterm birth, a global concern, prompted a study examining whether a prior preterm singleton birth raises the risk of preterm birth in subsequent twin pregnancies. Conducting a systematic review of 460 studies, only eight met the eligibility criteria. The meta-analysis revealed a 9.5% incidence of preterm singleton births in subsequent twin pregnancies. Further analysis demonstrated a significantly elevated risk of preterm twin births at <32 weeks for those with a history of preterm singleton births. The study concludes that a consistent and statistically significant association exists between prior preterm singleton births and increased preterm twin birth risk at various gestational ages. This underscores the importance of considering obstetric history in assessing preterm birth risk in twin pregnancies. Clinicians are advised to closely monitor pregnancies with a history of preterm singleton births for interventions targeted and improved prenatal care.

Pregnancy outcomes of foetal reduction from twin to singleton gestation compared to ongoing twin gestations: a systematic review and meta-analysis.

BACKGROUND: Foetal reduction, which involves selectively terminating one or more foetuses in a multiple gestation pregnancy, has become more common. This systematic review and meta-analysis aims to assess and compare pregnancy outcomes of foetal reduction from twin to singleton gestation to ongoing twin gestations. METHODS: A comprehensive search of electronic databases (MEDLINE, EMbase, Cochrane Library, CINAHL and PsycINFO) was done for studies published until 15 April 2023. The outcomes analysed included gestational diabetes mellitus (DM), hypertension, caesarean delivery, foetal loss, perinatal death, preterm birth (PTB), intrauterine growth restriction (IUGR), preterm prelabour rupture of membranes (PPROM) and birth weight. RESULTS: A total of 13 studies comprising 1241 cases of twin to singleton foetal reduction gestation were compared to 20,693 ongoing twin gestations. Our findings indicate that foetal reduction was associated with a significantly lower risk of developing maternal gestational DM (odds ratio [OR] = 0.40, 95% confidence interval [CI] 0.27-0.59) and hypertension (OR = 0.36, 95% CI 0.23-0.57) compared to the control group. Incidence rate of caesarean delivery (OR = 0.65, 95% CI 0.53-0.81) after foetal reduction was significantly lower compared to ongoing twin gestations. There was a 63% lower chance of PTB before 37 weeks of pregnancy. However, there was no significant association between foetal reduction and outcomes such as foetal loss, perinatal death, IUGR and PPROM. CONCLUSIONS: Our findings suggest that foetal twin to singleton reduction entails potential benefits as compared to ongoing twin gestations. Further well planned studies are needed to explore underlying mechanisms to understanding of the outcomes associated with foetal reduction procedures and inform clinical decision-making for pregnant individuals and healthcare providers alike.

Foetal reduction, a procedure where one or more foetuses in a twin pregnancy are selectively terminated, has become more common. This study reviewed existing research to compare the outcomes of foetal reduction to singleton pregnancies with those of ongoing twin pregnancies. The study found that mothers who underwent foetal reduction had a lower risk of developing gestational diabetes and hypertension, and they were less likely to have a caesarean delivery. There was also a reduced chance of preterm birth before 37 weeks. However, foetal reduction did not appear to significantly impact outcomes like foetal loss, perinatal death, intrauterine growth restriction or preterm pre-labour rupture of membranes. It is important to note that there is some variation in the results among different studies, and more research is needed to fully understand these findings.

Tubo-Ovarian ectopic pregnancy: A rare twin ectopic pregnancy.

The most common twin ectopic pregnancy is heterotopic (1/7000). We are reporting a rare case of twin tubo-ovarian ectopic pregnancy, which was presented in the emergency department of Ayub Teaching Hospital Abbottabad. A 30- year-old female arrived with worsening lower abdominal pain persisting for three weeks. She also had per-vaginal bleeding with passage of clots 1week ago. Clinical examination revealed a tense abdomen with tenderness in the left iliac fossa. Per-vaginally, there was cervical motion tenderness and fullness in the posterior fornix. Beta HCG level revealed a sub-optimal rise whereas Transabdominal ultrasound showed an echogenic shadow in the left ovary. The uterus appeared normal. On exploratory laparotomy a large left ovarian mass was seen with ruptured chronic right tubal pregnancy with adhesions. On cut-section of the ovary, a small foetus was evident. We have concluded that in case of subacute abdominal pain and an-echogenic mass on ultrasonography in reproductive age contralateral adnexa should be accessed to exclude contralateral ectopic pregnancy.

Characteristics of unilateral and bilateral bovine twin foetuses.

Twin pregnancy in cattle is undesirable for a number of reasons, including a higher abortion risk compared to pregnancies with a single foetus. Yet, the abortion risk is significantly influenced by the intrauterine location of the foetuses, that is, the abortion risk is several times higher if they are implanted in the same uterine horn (unilateral twin pregnancy) than if they are implanted with one foetus in each uterine horn (bilateral twin pregnancy). The reason for the higher abortion risk in unilateral twin pregnancies is unknown, but it may be related to malnutrition of the outermost foetus due to a limited placental capacity, as is the case for equine twin foetuses. A slaughterhouse study was performed and the foetuses of cattle pregnant with twins were measured. We identified 65 cases of twin pregnancies, of which 35 were unilateral twin pregnancies and 30 were bilateral twin pregnancies. There was no significant difference between the outermost and the more centrally located foetus in unilateral twin pregnancies in terms of body weight and length of the metacarpal diaphysis. Growth retardation of the outermost foetus could therefore not be confirmed as the cause of the higher abortion risk in unilateral bovine twin pregnancies. Four cases of pre-slaughter foetal mortality were identified. In three of these cases, both twins were dead, of equal size and at a comparable level of degradation. In the fourth case, with approximately 40-day-old twin foetuses of equal size, only one of the foetuses showed signs of pre-slaughter death.

Cephalopagus twins diagnosed at 7 weeks gestational age following IVF/ICSI.

A patient in her 30s who was a G0 proceeded with in vitro fertilisation (IVF) for a history of male factor infertility. Following single embryo transfer, the patient was diagnosed with a conjoined twin pregnancy. During her IVF cycle, the patient was stimulated with an antagonist protocol for 13 days followed by a gonadotropin-releasing hormone agonist trigger. 13 eggs were retrieved, 9 were mature and 5 fertilised with intracytoplasmic sperm injection. Of those, two were cryopreserved. She had a successful frozen blastocyst embryo transfer. The patient's 7-week ultrasound demonstrated a single gestational sac, yolk sac and fetal pole. However, the crown-rump length appeared visually abnormal and two heartbeats were visualised. She was referred to maternal-fetal medicine (MFM) for a first-trimester ultrasound. Her ultrasound with MFM was notable for a fluid-filled chest, foreshortened limbs and early sacral agenesis. She was subsequently diagnosed with cephalopagus twins and underwent an induced abortion following consultation with MFM.

Inflammatory markers in relation to maternal lifestyle and adverse pregnancy outcomes in twin pregnancies.

It is well known that inflammatory markers play an important role in the development and maintenance of healthy pregnancies. However, the literature regarding inflammation in relation to lifestyle and adverse pregnancy outcomes in twin pregnancies is remarkably uncovered. Therefore, this study aimed at evaluating the concentration of inflammatory markers in dried capillary blood spot samples from 523 women with twin pregnancies, included at a median gestational age of 21+1 weeks. The relationship between inflammatory markers and maternal lifestyle (current smoking status and pre-pregnancy body mass index) in addition to adverse pregnancy outcomes (preeclampsia, gestational diabetes mellitus, and small for gestational age) was analyzed. The study showed that active smoking at inclusion was associated with an elevated concentration of interleukin-8. Furthermore, maternal obesity was associated with an elevated concentration of C-reactive protein and monocyte chemoattractant protein-1. Analysis of the data showed no statistically significant variations in the concentration of the assessed inflammatory markers for neither preeclampsia, gestational diabetes mellitus, nor small for gestational age. The current study promotes future research on the pathophysiology of twin pregnancies in relation to adverse pregnancy outcomes, as the literature within the area remains scarce.

The impact of fetal sex on pregnancy and neonatal outcomes in twin gestation.

PURPOSE: Fetal sex is independently associated with pregnancy complications and impacts neonatal outcomes. Evidence suggests that females have an advantage over males, with a better outcome in the perinatal period. In addition, fetal outcome in twin gestations is also related to the intrauterine position of the fetus, such as the first, the presenting or second twin. It has been demonstrated that the neonatal outcome of the second fetus is worse than that of the first fetus. This study aimed to examine the influence of fetal sex on obstetric outcomes in twin pregnancies based on the location of the fetus in the uterus. METHODS: Retrospective study. Maternal and obstetric outcomes were compared among three groups: male‒male, female‒female, and male‒female groups. Comparisons of neonatal outcomes were performed among the four groups: male A-male B, male A-female B, female A-male B, and female A-female B. RESULTS: A total of 1073 twin gestations were included, comprising 288 male‒male, 288 female‒female, and 497 male‒female gestations. A greater percentage of neonates admitted to the NICU was observed for male fetuses than for female fetuses. Adverse composite neonatal outcome was more common in the male‒male group than in the female‒male group and in the female‒female group. CONCLUSION: Twin gestation with a first twin male tends to have worse neonatal outcomes than does twin gestation with a first twin female. The presence of a male co-twin increases the risk of adverse outcomes.

Neonatal respiratory complications in twins at 36-38 weeks of gestation.

BACKGROUND: Twin pregnancies are associated with a high risk of perinatal mortality and morbidity. Late preterm or early term delivery is frequently performed to avoid unexpected fetal death in uncomplicated twin pregnancies. Nonetheless, delivery before full term is associated with neonatal respiratory complications. This study aimed to evaluate perinatal respiratory complications in twins delivered between 36 and 38 weeks of gestation. METHODS: A retrospective cohort study was conducted on twins delivered between 36 and 38 weeks of gestation from January 2008 to June 2020. The primary outcomes were the incidence of composite neonatal respiratory morbidity, which included respiratory distress syndrome, transient tachypnea of the newborn, meconium aspiration syndrome, mechanical ventilation or continuous positive airway pressure according to gestational age at delivery, and chorionicity. The relationship between gestational age at delivery and composite neonatal respiratory morbidity was evaluated using multivariate logistic regression analysis adjusted for potential confounders. RESULTS: This study included 1608 twins (614 monochorionic diamniotic twins, 994 dichorionic diamniotic twins). At 36, 37, and 38 weeks of gestation, the frequencies of composite neonatal respiratory morbidity were 19.4%, 10.7%, and 9.2% in dichorionic diamniotic twins and 13.6%, 8.7%, and 9.4% in monochorionic diamniotic twins, respectively. In dichorionic diamniotic twins, the composite neonatal respiratory morbidity rate was higher for twins delivered at 36 weeks of gestation than for those delivered at 37 weeks. No significant differences between monochorionic diamniotic twins were detected. CONCLUSIONS: In uncomplicated dichorionic diamniotic twin pregnancies, delivery should be considered after 37 weeks of gestation to reduce neonatal respiratory complications.

Cesarean section prior to 28 weeks' gestation: which type of uterine incision is optimal?

OBJECTIVE: The purpose of this study was to determine the factors that influence physician preference for type of hysterotomy incisions in gravidas with a singleton or twin pregnancy undergoing cesarean section under 28 weeks, and to assess factors that result in delivery complications, defined as either intraoperative dystocia or hysterotomy extension. We hypothesized that compared to those with non-cephalic presentations, gravidas with a presenting fetus in cephalic presentation would have higher rates of low-transverse cesarean section, and reduced rates of delivery complications with low-transverse hysterotomy. METHODS: This was a retrospective cohort chart analysis of 128 gravidas between 23 0/7 and 27 6/7 weeks undergoing cesarean section at a single academic institution between August 2010 and December 2022. Data was abstracted for factors that might influence the decision for hysterotomy incision type, as well as for documentation of difficulty with delivery of the fetus or need for hysterotomy extension to affect delivery. RESULTS: There was a total of 128 subjects, 113 with a singleton gestation and 15 with twins. The presenting fetus was in cephalic presentation in 43 (33.6%), breech presentation in 71 (55.5%), transverse/oblique lie in 13 (10.2%), and not documented in 1 (0.8%). Sixty-eight (53.1%) had a low-transverse cesarean section (LTCS), 53 (41.4%) had a Classical, 5 (3.9%) had a low-vertical hysterotomy and 2 (1.6%) had a mid-transverse incision. There was a significantly higher rate of LTCS among gravidas with the presenting fetus in cephalic presentation (30/43, 69.8%) compared to those with breech (31/71, 43.7%) or transverse/oblique presentations (7/13, 53.8%), p = .03. No other significant associations were related to hysterotomy incision, including nulliparity, racially or ethnically minoritized status, plurality, indication for cesarean delivery, or pre-cesarean labor. Twenty (15.6%) subjects experienced either an intraoperative dystocia or hysterotomy extension. For the entire cohort, there was a greater median cervical dilatation in those with delivery complications (4.0 cm, IQR .5 - 10 cm) compared to those without complications (1.5, IQR 0 - 4.0), p = .03, but no significant association between delivery complications and fetal presentation, hysterotomy type, plurality, or other demographic/obstetrical factors. However, among gravidas undergoing low-transverse cesarean section, only 2/30 (6.7%) with cephalic presentations had a delivery complication, compared to 9/31 (29.0%) with breech presentations and 3/7 (42.9%) with a transverse/oblique lie, p = .03. CONCLUSION: In pregnancies under 28 weeks, the performance of a low-transverse cesarean section was significantly associated only with presentation of the presenting fetus. Among those with cephalic presentations, the rate of intrapartum dystocia or hysterotomy extension was low after a low-transverse hysterotomy, suggesting that in this subgroup, a low-transverse cesarean section should be considered.

Intertwin discordance of aldosterone levels in amniotic fluid with placental anastomoses in monochorionic twins: Insight into the pathophysiology of twin-to-twin transfusion syndrome.

INTRODUCTION: Our objective was to investigate the association between the presence of placental anastomoses and intertwin differences in renin-angiotensin-aldosterone activation in monochorionic twins using amniotic fluid aldosterone (AF-ALD) levels. In addition, this study also examined the association between AF-ALD and the ALD levels in the umbilical cord blood (UCB-ALD) in monochorionic twins. MATERIAL AND METHODS: This prospective study included monochorionic diamniotic (MD) twin pregnancies that were not complicated by twin-to-twin transfusion syndrome (TTTS) at delivery. Amniotic fluid and umbilical cord vein blood samples were collected from each twin at delivery, and the ALD levels were measured subsequently. The MD twins were divided into two groups: those with placental anastomoses and those without anastomoses owing to fetoscopic laser surgery. The differences in the AF-ALD levels between the larger and smaller twins were analyzed. RESULTS: The AF-ALD levels showed a strong and significant positive correlation with UCB-ALD levels in 131 MD twins (r = 0.804, p < 0.001). Intertwin differences were examined in 41 and 28 pairs of MD twins with and without placental anastomoses, respectively. The AF-ALD levels in the smaller twins were significantly higher than those in the larger twins among the pairs of MD twins with placental anastomoses (p = 0.003); however, no statistically significant intertwin differences were observed among the twins without placental anastomoses (p > 0.05). CONCLUSIONS: The AF-ALD levels reflect the UCB-ALD levels in MD twins. The presence of placental anastomoses led to intertwin discordance in the ALD levels in MD twins even uncomplicated with TTTS. It was considered that monochorionic twins have this clinical background, and it leads to the development of TTTS.