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.

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.

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.

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.

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.

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.

Dichorionic diamniotic twin pregnancy after preimplantation genetic testing and single blastocyst transfer.

BACKGROUND: In addition to the potential for multiple pregnancies, natural conception occurring in preimplantation genetic testing (PGT) increases undesired genetic risk. Some studies showed that a dichorionic diamniotic twin pregnancy after a single blastocyst transfer could be caused by embryo splitting or concurrent spontaneous conception. CASE: We describe a patient undergoing PGT who had a dichorionic diamniotic twin pregnancy after single blastocyst transfer in a natural cycle. In this case, we recommended to determine genetic status of the twins by prenatal diagnosis. The results showed that karyotype, chromosome copy number variation, and parental ACAT1 variation of the twins were all normal and similar. To investigate the origin of pregnancy, we used the genotype data of single-nucleotide polymorphisms typical of genome-wide association studies. Dizygotic twins were inferred by robust estimation of kinship coefficients, which confirmed the occurrence of a spontaneous conception. CONCLUSIONS: This case strengthens the importance of genetic counseling to inform couples with reproductive genetic risk, such as those who undergo PGT, that intercourse should be avoided, especially in natural transfer cycles. Moreover, prenatal diagnosis remains essential and is strongly recommended to avoid genetic risks.

Changes in cytokine and sequestosome-1 levels during twin pregnancy progression: Association with outcome.

BACKGROUND: Twin pregnancies are associated with complications and adverse outcomes. The number of twin pregnancies has increased in the last decades, due to the use of assisted reproductive techniques and delayed childbearing. Analysis of changes that occur during twin pregnancy progression and their association with outcome will lead to improved clinical interventions. OBJECTIVE: We evaluated if the plasma concentration of select cytokines and the level of sequestosome-1 (p62) in peripheral blood mononuclear cells (PBMCs) during each trimester of twin gestations was predictive of pregnancy outcome. STUDY DESIGN: This prospective, observational study was conducted at Careggi University Hospital, Florence, Italy. Plasma from 82 women with twin pregnancies was collected in each trimester for measurement of interleukin (IL)-1ß, IL-6, IL-10, IL-12 and tumor necrosis factor (TNF)-α. The intracellular PBMC concentration of p62, a protein involved in autophagy, kinase activity and cell differentiation, was also determined. RESULTS: IL-1ß (p < 0.001), IL-6 (p < 0.001), TNF-α (p < 0.001) and p62 (p < 0.05) increased from the 1st to the 2nd to the 3rd trimester. The TNF-α level was correlated with the IL-1ß concentration in the 1st and 3rd trimesters p < 0.01) and with the IL-6 concentration in each of the three trimesters (p < 0.01). The intracellular p62 level in PBMCs was negatively correlated with the concentration of IL-1ß in the 2nd trimester (p < 0.05) and negatively correlated with the IL-6 level in the 3rd trimester (p < 0.05). The TNF-α level was significantly higher in the 2nd (p < 0.05) and 3rd (p < 0.001) trimester in women with a spontaneous preterm delivery. The TNF-α concentrations in the 2nd (p < 0.05) and 3rd (p < 0.01) trimester, respectively, and 3rd trimester IL-6 (p < 0.01), were negatively associated with gestational age at delivery. The concentration of IL-6 was highest in the 2nd (p < 0.05) and 3rd (p < 0.05) trimesters in women who utilized assisted reproductive technologies. An elevated IL-1ß level in the 3rd trimester was associated with gestational diabetes mellitus (p < 0.05). CONCLUSION: Variations in cytokine levels between individual women during the three trimesters of twin gestations are predictive of spontaneous preterm delivery and the onset of gestational diabetes.

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.

Monochorionic Twin Complications and Fetoscopic Interventions.

Monochorionic twins are at risk for complications due to the presence of placental vascular anastomoses, including twin-twin transfusion syndrome, twin anemia-polycythemia sequence, selective fetal growth restriction, and twin reversed arterial perfusion sequence. While ultrasound is the primary modality to screen for the development of these complications, MRI plays an important role in assessing monochorionic twin pregnancies for the development of other complications, such as neurologic injury. In this article, the authors review the ultrasound imaging findings associated with monochorionic twin complications, management options, and the role for MRI in these pregnancies.

Risk Factors for Postpartum Hemorrhage in Severe Pre-Eclampsia: A Retrospective Single-Centre Study of 1953 Cases.

BACKGROUND Severe pre-eclampsia (sPE) and postpartum hemorrhage (PPH) in pregnancy have serious impact on maternal and fetal health and life. Co-occurrence of sPE and PPH often leads to poor pregnancy outcomes. We explored risk factors associated with PPH in women with sPE. MATERIAL AND METHODS This retrospective study included 1953 women with sPE who delivered at the Women's Hospital of Nanjing Medical University between April 2015 and April 2023. Risk factors for developing PPH in sPE were analyzed, and subgroups were analyzed by delivery mode (cesarean and vaginal). RESULTS A total of 197 women with PPH and 1756 women without PPH were included. Binary logistic regression results showed twin pregnancy (P<0.001), placenta accreta spectrum disorders (P=0.045), and placenta previa (P<0.001) were independent risk factors for PPH in women with sPE. Subgroup analysis showed risk factors for PPH in cesarean delivery group were the same as in the total population, but vaginal delivery did not reduce risk of PPH. Spinal anesthesia reduced risk of PPH relative to general anesthesia (P=0.034). Vaginal delivery group had no independent risk factors for PPH; however, magnesium sulfate (P=0.041) reduced PPH incidence. CONCLUSIONS Women with twin pregnancy, placenta accreta spectrum disorders, placenta previa, and assisted reproduction with sPE should be alerted to the risk of PPH, and spinal anesthesia should be preferred in cesarean delivery. Magnesium sulfate should be used aggressively in women with sPE; however, the relationship between magnesium sulfate and PPH risk needs further investigation.

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.

Pregnancy outcomes of cerclage in twin gestations: a multicenter retrospective cohort study.

OBJECTIVES: To determine the effects of cerclage on twin pregnancies. METHODS: A multicenter, retrospective, cohort study was conducted at 10 tertiary centers using a web-based data collection platform. The study population included twin pregnancies delivered after 20 weeks of gestation. Patients with one or two fetal deaths before 20 weeks of gestation were excluded. Maternal characteristics, including prenatal cervical length (CL) and obstetric outcomes, were retrieved from the electronic medical records. RESULTS: A total of 1,473 patients had available data regarding the CL measured before 24 weeks of gestation. Seven patients without CL data obtained prior to cerclage were excluded from the analysis. The study population was divided into two groups according to the CL measured during the mid-trimester: the CL ≤2.5 cm group (n = 127) and the CL >2.5 cm group (n = 1,339). A total of 127 patients (8.7%) were included in the CL ≤2.5 cm group, including 41.7% (53/127) who received cerclage. Patients in the CL >2.5 cm group who received cerclage had significantly lower gestational age at delivery than the control group (hazard ratio (HR): 1.8; 95% confidence interval (CI): 1.11-2.87; p = .016). Patients in the CL ≤2.5 cm group who received cerclage had a significantly higher gestational age at delivery than the control group (HR: 0.5; 95% CI: 0.30-0.82; p value = .006). CONCLUSIONS: In twin pregnancies with a CL ≤2.5 cm, cerclage significantly prolongs gestation. However, unnecessary cerclage in women with a CL >2.5 cm may result in a higher risk of preterm labor and histologic chorioamnionitis although this study has a limitation originated from retrospective design.

Prognosis of remaining fetus in twin pregnancy after demise of one fetus according to its location.

BACKGROUND: To investigate the prognosis of the remaining fetus in twin pregnancy after experiencing one fetal demise in the first trimester according to the location of the demised fetus. METHODS: This was a retrospective study of twin pregnancies with one fetal demise after the first trimester (14 weeks of gestation) delivered between September 2004 and September 2022. The study population was divided into two groups based on the location of the demised fetus as determined by the last recorded ultrasonography results: Group 1 included twin pregnancies where the presenting fetus was demised (n = 36) and Group 2 included twin pregnancies where the non-presenting fetus was demised (n = 44). The obstetric and neonatal outcomes were also reviewed. RESULTS: A total of 80 pregnant women were included. The median gestational age for the diagnosis of fetal demise was 24.1 weeks. The gestational age of the demised fetus was not different between Groups 1 and 2; however, the gestational age of the remaining fetus at delivery was significantly earlier in Group 1 than it was in Group 2 (33.8 vs. 37.3 weeks, P = .004). The rate of preterm birth before 28 weeks was almost five times higher in Group 1 than in Group 2 (22.2% vs. 4.5%, P = .037). Regression analysis demonstrated significant differences between Groups 1 and 2. Respiratory distress syndrome, bronchopulmonary dysplasia, patent ductus arteriosus, retinopathy of prematurity, and jaundice were more common in Group 1 than in Group 2; however, the association was not significant after adjusting for gestational age at delivery. CONCLUSIONS: When the presenting fetus is demised in a twin pregnancy, the remaining fetus tends to be delivered earlier than when the non-presenting fetus is demised.

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.

Magnetic resonance imaging of intracranial anomalies in pregnancies complicated by twin anemia-polycythemia sequence.

PURPOSE: To describe fetal brain Magnetic Resonance Imaging (MRI) findings in a large series of monochorionic (MC) pregnancies complicated by Twin Anemia-Polycythemia Sequence (TAPS) prenatally diagnosed, so to characterize the potential intracranial complications associated with this condition, their frequency and potential treatment options. METHODS: This is a retrospective study of MC twin pregnancies complicated by TAPS and undergone fetal MRI in a single institution from 2006 to 2023. MRI control was performed and post-natal ultrasound (US) or MRI were available. RESULTS: 1250 MC pregnancies were evaluated in our institution. 50 pregnancies (4%) were diagnosed with TAPS, 29 underwent a fetal brain MRI. 13/29 pregnancies (44.8%) demonstrated brain findings at MRI in at least a twin. Neuroradiological findings were detected in 14/57 twins (24.6%). We detected four main categories of findings: hemorrhagic lesions, T2-weighted white-matter hyperintensities (WMH), brain edema-swelling and venous congestion. Nineteen findings were present in the anemic and three in the polycythemic twins, with a statistically significant ratio between the two groups (p-value = 0.01). Intrauterine MRI follow-up demonstrated the sequalae of hemorrhagic lesions. A complete regression of brain swelling, veins prominence and T2-WMHs was demonstrated after treatment. Postnatal imaging confirmed prenatal features. CONCLUSIONS: Our work demonstrates that TAPS-related MRI anomalies consisted in edematous/hemorrhagic lesions that occur mostly in anemic rather than in polycythemic twins. Fetoscopic laser surgery could have a potential decongestant role. Therefore, prenatal MRI may help in counselling and management in TAPS pregnancies, especially for the planning of therapy and the monitoring of its efficacy.

Vaccination in twin pregnancies: comparison between immunization before conception and during pregnancy.

To evaluate the development of neutralizing Anti-Spike Protein IgG (Anti-S-IgG) during twin pregnancies before conception vs. during pregnancy. In this prospective study, three blood samples were collected from pregnant women and subjected to anti-S-IgG immunodiagnostics. The patient's medical records, including vaccination and PCR test results, were collected from the hospital's electronic database. Age-matched non-pregnant women were used as a control group. We enrolled 83 women with twin pregnancies. 49 women were vaccinated before conception, 21 women were vaccinated during pregnancy, and 13 were not vaccinated. Of the 13 women who weren't vaccinated, three became positive during pregnancy, and all three were severely ill. By contrast, in women who were vaccinated during or before pregnancy, COVID-19 infection during pregnancy caused only mild symptoms. A ten-fold lower level of neutralizing Anti-S-IgG in the 3rd trimester was observed in healthy women who were vaccinated before conception and remained healthy until discharge from the hospital after delivery 1605 (IQR: 763-2410) compared to the healthy women who were vaccinated during pregnancy 152 AU/mL (IQR: 54-360). This difference was higher among women who were infected by COVID-19 (as verified by a positive PCR test). The third-trimester level of neutralizing Ant-S-IgG in the infected group was 4770 AU/mL (4760-6100) in infected women vaccinated before conception compared to those vaccinated during pregnancy who had 70 AU/mL (IQR: 20-170) (p < 0.001). In women vaccinated at 13-16 weeks gestation, neutralizing Anti-S-IgG at 20-22 weeks went up to 372 AU/mL (IQR: 120-1598) but rapidly dropped to 112 AU/mL (IQR: 54-357) at 28-30 weeks, (p < 0.001), a faster decline than in women vaccinated at a median 22 weeks before conception. Being infected by COVID-19 before conception was linked to having low Anti-S-IgG levels during pregnancy, whereas being infected by COVID-19 during pregnancy led to a very high response in the 3rd trimester. In twin pregnancies, significantly lower neutralizing Anti-S-IgG levels were observed in women vaccinated during pregnancy compared to those vaccinated before conception, whether infected or not infected by COVID-19. A full course of vaccination before conception is recommended.Trial registration. ClinicalTrials.gov Protocol Registration and Results System (PRS) Receipt Release Date: October 4, 2021. https://clinicaltrials.gov/ ID: NCT04595214.