An association of chorionicity with preterm twin birth

A Comparison of Preterm Birth Rate and Growth from Birth to 18 Years Old between in Vitro Fertilization and Spontaneous Conception of Twins

The aim of the present study was to compare the rate of preterm birth (PTB) and growth from birth to 18 years between twins conceived by in vitro fertilization (IVF) and twins conceived by spontaneous conception (SC) in mainland China. The retrospective cohort study included 1164 twins resulting from IVF and 25,654 twins conceived spontaneously, of which 494 from IVF and 6338 from SC were opposite-sex twins. PTB and low birth weight (LBW), and growth, including length/height and weight, were compared between the two groups at five stages: infancy (0 year), toddler period (1-2 years), preschool (3-5 years), primary or elementary school (6-11 years), and adolescence (10-18 years). Few statistically significant differences were found for LBW and growth between the two groups after adjusting for PTB and other confounders. Twins born by IVF faced an increased risk of PTB compared with those born by SC (adjusted odds ratio [aOR] 8.21, 95% confidence interval [CI] [3.19, 21.13], p < .001 in all twins and aOR 10.12, 95% CI [2.32, 44.04], p = .002 in opposite-sex twins). Twins born by IVF experienced a similar growth at five stages (0-18 years old) when compared with those born by SC. PTB risk, however, is significantly higher for twins conceived by IVF than those conceived by SC.

Obstetric and perinatal outcomes of dizygotic twin pregnancies resulting from in vitro fertilization versus spontaneous conception: a retrospective study

This study was designed to to assess perinatal and neonatal outcomes of dizygotic twin pregnancies conceived naturally or by in vitro fertilization (IVF). After strict selection, the study included 470 dizygotic twin pregnancies. There were 249 resulting from IVF treatments and 221 conceiving spontaneously. After adjusting maternal age and primiparity, the results showed that there were no significant differences between the two groups (P > 0.05) in terms of maternal antenatal complications and neonatal outcomes. In conclusion, our study does not reveal increased risks for pregnancy-related complications and adverse neonatal outcomes in dizygotic twin pregnancies following IVF treatments. With these fundamental data, this study could provide a reference for perinatal care and clinical assisted reproductive technology (ART) treatment and help to inform infertile parents about the potential risks of IVF treatments.

Presence of an umbilical artery notch in monochorionic/monoamniotic twins

OBJECTIVE

To examine the association between an umbilical artery notch and fetal deterioration in monochorionic/monoamniotic (MC/MA) twins.

METHODS

Six MC/MA twin pregnancies were admitted at 24-28 weeks of gestation for close fetal surveillance until elective delivery at 32 weeks or earlier in the presence of signs of fetal deterioration. Ultrasound (US) examinations were performed twice weekly. The presence of cord entanglement, umbilical artery notch, abnormal Doppler parameters, a non-reassuring fetal heart rate pattern, or an abnormal fetal biophysical profile were evaluated.

RESULTS

Umbilical cord entanglement was observed on US in all pregnancies. The presence of an umbilical artery notch was noted in four out of six pregnancies and in two of them an umbilical artery notch was seen in both twins. The umbilical artery pulsatility index was normal in all fetuses. Doppler parameters of the middle cerebral artery and ductus venosus, fetal biophysical profile and fetal heart rate monitoring remained normal until delivery in all pregnancies. All neonates experienced morbidity related to prematurity; however, all were discharged home in good condition.

CONCLUSION

The presence of an umbilical artery notch and cord entanglement, without other signs of fetal deterioration, are not indicative of an adverse perinatal outcome.

Obstetric and Perinatal Outcomes of Dichorionic Twin Pregnancies According to Methods of Conception: Spontaneous Versus In-Vitro Fertilization

We have observed the inconsistent findings from various studies on twin pregnancy outcomes obtained by assisted reproductive technology and spontaneous conception. In most studies, however, the concrete chorionicity, regarded as a confounding factor for predicting the perinatal outcomes of twin pregnancies, has not been determined. The purpose of this study was to compare obstetric and perinatal outcomes of only the dichorionic twin pregnancies according to the methods of conception: spontaneous and in-vitro fertilization (IVF). The twin pairs with dichorionicity reported from 1995 to 2008 were investigated and we divided them into two groups which consisted of 286 and 134 twins by spontaneous conception and IVF, respectively. Odds ratios for associations between IVF and pregnancy outcomes were analyzed after adjustment for maternal age and parity. There were no risk differences between the two groups regarding the obstetric complications, which include preterm delivery, preterm labor, preterm premature rupture of membranes, preeclampsia, placenta previa, and abruption. Any differences were not shown in the two groups for the risk estimates of perinatal outcomes, such as low birthweight, very low birthweight, small for gestational age, Apgar scores of < 7 at 5 minutes, discordance in birthweights, congenital anomalies and mortality. However, twins conceived after IVF were less likely to be admitted to the neonatal intensive care unit than those conceived spontaneously (adjusted OR 0.488; 95% confidence interval 0.261–0.910). In the cases of dichorionic twins, IVF may not be associated with adverse perinatal and obstetric outcomes compared with spontaneous conception.

Maternal obesity as a risk factor for very pre-term delivery in dichorionic twin pregnancies

We attempt here to identify the maternal characteristic factors most strongly associated with the increased risk of very pre-term delivery in dichorionic twin deliveries. Data were collected from 24 dichorionic twin pregnancies who were born at <32 weeks' gestation (very pre-term delivery) and 245 dichorionic twin pregnancies, who were born at 37-40 weeks' gestation as controls. Data included maternal age, height, body weight, body mass index (BMI), history of abortion, parity, maternal smoking, history of infertility therapy, such as in vitro fertilisation and/or embryo reduction, chronic hypertension and diabetes mellitus. Using logistic regression, the risk of very pre-term delivery was significantly increased among obese women (BMI >or=30 during prepregnancy; the adjusted odds ratio: 5.1, 95% confidence intervals: 1.2-21, p = 0.01). The current results indicate that maternal obesity is an independent risk factor for very pre-term delivery in dichorionic twin pregnancies.

The impact of fetal gender on prematurity in dichorionic twin gestations after in vitro fertilization

BACKGROUND

Impact of fetal gender on prematurity has been primarily investigated in singleton pregnancies. In an attempt to understand better how fetal gender may affect gestational length in twin gestations after in vitro fertilization, same-sex twins and opposite twins were compared for pregnancy duration.

METHODS

This study evaluated 113 women at ages 20 to 39 years with consecutive dichorionic-diamniotic twin gestations after assisted reproduction. All pregnancies were results of fresh in vitro fertilization (IVF) cycles with use of autologous oocytes and sperm and were delivered at up to 37 weeks of gestation at a University-based high-risk, maternal-fetal medicine unit.

RESULTS

Both groups did not differ in baseline characteristics, such as maternal ages, indications for fertility treatments, number of previous IVF attempts, body mass index and parity. Opposite sex- twins, however, presented with significantly shorter gestational age at birth (32.9 +/- 3.4 weeks) than same-sex twins (34.3 +/- 2.5 weeks), (p < 0.05). Younger maternal age was also associated with shorter pregnancy duration (p < 0.05).

CONCLUSIONS

Fetal gender mix serves as risk factor for more significant prematurity in dichorionic-diamniotic twins after assisted reproduction with opposite sex twins at higher risk than same sex-twins.

Uncomplicated monochorionic diamniotic twin pregnancy

There have been significant advances in our understanding of the aetiology and management of disorders specific to Monochorionic Diamniotic (MCDA) twin pregnancies like Twin-Twin Transfusion Syndrome (TTTS) and Twin Reversed Arterial Perfusion (TRAP) but there is paucity of data about the management of uncomplicated MCDA twins pregnancies. It is accepted that even in the absence of specific complications, these pregnancies are associated with increased perinatal morbidity & mortality. The aim of this review is to gather evidence regarding the management of seemingly uncomplicated monochorionic diamniotic pregnancies.

A retrospective analysis of placentas from twin pregnancies derived from assisted reproductive technology

There are conflicting studies associating twin pregnancies derived from assisted reproductive technology (ART) with preterm birth, low birthweight, and other negative outcomes. This work investigates whether ART is linked with any placental pathology, given that placentation significantly influences fetal development. A 5-year, retrospective cohort study was conducted on placentas from twin pregnancies. The placental information from 417 patients was divided into two groups: placentas derived from ART and placentas derived from spontaneous pregnancies (non-ART). Available clinical information and pathologic findings from both groups then were compared. There was no statistical difference in the prevalence of placental pathology between the non-ART and ART cohorts (i.e., cord insertion, single umbilical artery, cord knot, retroplacental hemorrhage, infarction, vasculopathy, vascular anastomoses, chorangiosis, villitis, deciduitis, chorioamnionitis, meconium staining). However, 8% of ART multiple pregnancies were monochorionic. While monochorionicity is a known risk factor for adverse obstetric and neonatal outcomes, the rate of monochorionic placentation did not increase as a result of ART. Nevertheless, it is interesting to note that this small percentage of monochorionic placentation occurred in the ART cohort despite the implantation of individual embryos. Overall, the data suggests that ART does not have a role in the pathologic placentation of twin pregnancies.

Genetic liability to schizophrenia in Oceanic Palau: a search in the affected and maternal generation

While liability to schizophrenia (Scz) is due to genetic and environmental factors, specific factors are largely unknown. We postulate a two-hit model for Scz, in which initial liability is generated during fetal brain development: this "hit" is precipitated by environmental stressors biologically interacting with maternal genetic vulnerability to the stress. Additional liability to Scz is generated by individual genetic vulnerability. To evaluate these putative levels of vulnerability, we search in the genome of both affected individuals and their mothers for variation that differs, statistically, from that in the general population. For parental analyses, mothers were treated as "affected," rather than their offspring, and the fathers were treated as "controls". We used a sample from the Palauan population: 175 individuals diagnosed with Scz, broadly defined; 87 mothers and 45 fathers of affected individuals. Pedigree and diagnostic data were available on 2,953 living and deceased subjects. DNA from 553 individuals was genotyped for short tandem repeats (STR) spaced approximately every 10 cM across the genome. We tested for association between affection status and STR alleles; such an approach was reasonable, despite the widely spaced markers, because this population has far-ranging linkage disequilibrium (LD). Results for the truly affected individuals were modest, whereas results from the maternal generation were promising. For a recessive model and a test for excess allele matching across mothers, significant findings occurred for D20S481, D10S1221, D6S1021, D13S317, and D18S976. Regions in which at least two adjacent markers produced substantial association statistics include 2p12-11.2, 2q24.1-32.1, 6q12-14.1, 10q23.2-24.21, 12q23.2-24.21 and 17q23.2-23.3.