Should multifetal pregnancy reduction be used for prevention of preterm deliveries in triplet or higher order multiple pregnancies?

This article reviews the arguments for the use of multifetal pregnancy reduction (MFPR) for the prevention of preterm deliveries in triplet and higher order multiple pregnancies and evaluates its effectiveness based on data from published studies. The arguments in favour of pregnancy reduction are based on the substantial mortality and morbidity associated with these pregnancies. Triplets and higher order multiples have increased rates of preterm delivery and intrauterine growth retardation, both of which are independent risk factors for death and handicap. Even controlling for gestational age, rates of mortality and handicap are higher for multiples than for singletons. Moreover, the family's risk of losing a child or having a handicapped child is greater because there are more infants at risk. MFPR effectively lowers these risk by reducing the frequency of preterm delivery. However, its effectiveness may be limited. In some studies, the proportion of preterm deliveries in reduced pregnancies remains above levels found in spontaneous twin or singleton pregnancies and MFPR does not appear to reduce the prevalence of low birth weight. Furthermore, the procedure itself has unwanted side effects: it increases the risk of miscarriage, premature rupture of the membranes and causes adverse psychological effects such as grief or depression for many patients. The authors note that a majority of the higher order multiple pregnancies result from a medical intervention in the first place, either through IVF techniques or the use of ovulation stimulation drugs. Although MFPR is an effective measure for reducing the substantial morbidity and mortality associated with higher order multiple pregnancies, preventive methods, such as limiting to 2 the number of embryos transferred for IVF and better control of the use of ovulation induction drugs, remain more effective and less intrusive.     

Is induction of labor risky for twins compare to singleton pregnancies?

Abstract

Objective: The aim of this study was to investigate whether induction of labor in twin pregnancies is associated with higher rates of maternal complications as compared to singletons.

Method: A retrospective population-based study was conducted to compare maternal complications following induction of labor in twin pregnancies and singletons at Soroka University Medical Center, Be'er-Sheva, Israel, between 1988 and 2010. Stratified analysis using a multiple logistic regression model was performed to control for confounders.

Results: The study population included 25?913 patients following induction of labor, of these 191 (0.73%) were in twin pregnancies. Induction of labor in twin pregnancies was not associated with adverse maternal outcomes such as cervical tears, third degree perineal tears, uterine rupture, peripartum hysterectomy, post-partum hemorrhage or retained placenta. However, labor induction in twins was significantly associated with cesarean deliveries (31.2% versus 17.1%; p?<?0.001).

Using a multivariable analysis controlling for confounders, induction at twins was an independent risk factor for cesarean delivery (CD; adjusted OR?=?2.2, 95% CI 1.7–2.7, p?<?0.001).

Conclusion: Induction of labor in twin pregnancies does not increase the risk for maternal complications. However, it is an independent risk factor for CD.     

Amniocentesis-related adverse outcomes in diamniotic twins: is there a difference compared to singleton pregnancies?

Objective

To investigate whether diamniotic twin gestations are at increased risk of amniocentesis-related adverse outcomes compared to singleton pregnancies.

Study design

This was a retrospective study of mid-trimester amniocenteses performed during the period 1993-2009. Cases were divided in two groups, one including singleton (Group 1) and the other diamniotic twin pregnancies (Group 2). All amniocentesis-related adverse outcomes were reviewed, including aspiration of insufficient amniotic fluid, aspiration of hemorrhagic amniotic fluid, repeated puncture and miscarriage. The incidence of these adverse outcomes was compared between the two groups.

Results

In total, 6270 cases were included in the study (Group 1, n = 6150 and Group 2, n = 120). Advanced maternal age was the main indication for amniocentesis in both singleton and twin pregnancies. There was no difference in the incidence of insufficient sample aspiration (0.2% in singletons vs. 0.0% in twins, P = NS), in the incidence of blood-stained amniotic fluid (3.7% in singletons vs. 4.6% in twins, P = NS), in the rate of need for second attempt (2.1% in singletons vs. 1.7% in twins, P = NS) or in the miscarriage rate (0.24% in singletons vs. 0% in twins).

Conclusion

In our experience, the incidence of amniocentesis-related adverse outcomes is not increased in diamniotic twins compared to singleton pregnancies.     

Fetal reduction from twins to a singleton: a reasonable consideration?

OBJECTIVE: In the past, our group took the position that we would not provide multifetal pregnancy reduction to a singleton regardless of starting number except for serious maternal medical indications or as a selective termination for diagnosed fetal anomalies. With evidence of increased safety and more women (many aged 40 years or more) asking for counseling about reduction to a singleton, we reviewed our prior reasoning. METHODS: We compared outcomes of 52 first-trimester twin-to-singleton for multifetal pregnancy reduction cases performed by a single operator to twin and singleton data from recent national register studies. RESULTS: Twin-to-singleton reductions represent less than 3% of all cases. Forty of 52 patients were aged 35 years or more, 19 were aged more than 40 years, and 2 were aged more than 50 years (age range 32-54 years). Since 1999, 23 of 28 had chorionic villus sampling before multifetal pregnancy reduction. Fifty-one of 52 reached viability with mean gestational age at delivery of 37.2 weeks. One of 52 patients miscarried (1.9%). Compared with multiple sources of data for twins, the loss rate is lower in twins reduced to a singleton. CONCLUSION: Until recently, multifetal pregnancy reductions to a singleton were rare. Physicians were concerned about the unknown risks of multifetal pregnancy reduction in this situation. They also had moral doubts about the justification to go "below twins." However, physicians know that spontaneous twin pregnancy losses average 8-10%. Also, with experience, multifetal pregnancy reduction has become very safe in our hands. Our data suggest that the likelihood of taking home a baby is higher after reduction than remaining with twins. We propose that twin-to-singleton reductions might be considered with appropriate constraints and safeguards.     

Velamentous cord insertion in monochorionic twins with or without twin–twin transfusion syndrome: Does it matter?

Objective

To study the association between velamentous cord insertion (VCI) and different outcomes in monochorionic twins with and without twin–twin transfusion syndrome (TTTS).

Methods

We recorded the cord insertion type in all consecutive monochorionic placentas examined in two tertiary medical centers. The association between VCI and several outcomes was estimated.

Results

A total of 630 monochorionic placentas with TTTS (n = 304) and without TTTS (n = 326) were studied. The incidence of VCI in the TTTS and non-TTTS group was 36.8% and 35.9%, respectively (P = 0.886). The presence of VCI in one twin was significantly associated with small for gestational age (SGA) status (odds ratio [OR] 1.45, 95% CI 1.13, 1.87) and severe birth weight discordance (OR 3.09, 95% CI 1.93, 4.96). Our results also showed significant interaction between TTTS and VCI when we considered intrauterine fetal demise (IUFD) and gestational age (GA) at birth. The prevalence of IUFD in monochorionic pregnancies without TTTS increased from 4.6% to 14.1% in the presence of VCI (P = 0.027). In the TTTS group, the prevalence of IUFD was comparable in the absence or presence of VCI. Similarly, GA at birth was significantly lower in the presence of VCI only in the non-TTTS group.

Conclusion

Our findings suggest that VCI is not associated with the development of TTTS but increases the risk of adverse outcomes. Both VCI and TTTS independently increase the prevalence of IUFD and lower GA at birth in a similar way, showing that VCI is an important indicator of adverse perinatal outcome in monochorionic twins.     

Does maternal glucose intolerance affect the length of gestation in singleton pregnancies?

OBJECTIVE: This study determined whether maternal glucose tolerance has a progressive effect on the length of gestation in singleton pregnancies and whether there is an increasing tendency towards spontaneous preterm birth with increasing glucose intolerance. METHODS: A total of 2,168 consecutive Chinese women with singleton pregnancies who underwent the 75-g oral glucose tolerance test (OGTT) over a 24-month period were categorized by their OGTT 2-hour value (mmol/L) into the following six groups: 5.9 or less, 6.0-6.9, 7.0-7.9, 8.0-8.9, 9.0-10.9, and 11.0 or greater mmol/L. Women with a 2-hour glucose value of 8.0 or more mmol/L were considered to have gestational diabetes mellitus (GDM) and received diet treatment. Women who eventually required insulin were excluded from the final analysis. The mean gestational age, birth weight, incidence of preterm birth, large for gestational age (LGA, birth weight > 90th percentile), and macrosomic (birth weight > or = 4.0 kg) infants were compared among the six groups. RESULTS: The incidence of preterm birth correlated significantly with increasing glucose intolerance. On further analysis, incidence of spontaneous birth before 37 weeks in the lowest to the highest 2-hour value groups was as follows: 5.5%, 2.6%, 3.7%, 4.9%, 8.5%, and 10.3% (P =.015) and that before 32 weeks went from 0.4%, 0.3%, 0.8%, 0.4%, 2.2%, to 3.4% (P =.018), respectively. There was no significant difference in the incidence of LGA or macrosomic infants. Regression analysis confirmed that the OGTT 2-hour glucose value was an independent determinant of gestational length. CONCLUSION: Gestational glucose intolerance affects gestation length and incidence of preterm birth, which should be considered a confounding factor in the analysis of the neonatal outcome of GDM pregnancies.     

What is the best measure of maternal complications of term pregnancy: ongoing pregnancies or pregnancies delivered?

OBJECTIVE: The purpose of this study was to determine whether rates of hypertensive disorders of pregnancy increase beyond 37 weeks of gestation and to address how best to analyze these rates. STUDY DESIGN: This was a retrospective cohort study of all women delivered beyond 37 weeks' gestational age from 1995 to 1999 at all Kaiser Permanente Medical Care Program delivery hospitals in Northern California. Rates of gestational hypertension, preeclampsia, and eclampsia were calculated by use of both pregnancy delivered (PD) and ongoing pregnancy (OP) as the denominator. Bivariate and multivariate analyses were conducted with use of P<.05 to indicate statistical significance. RESULTS: Among the 135,560 women in this cohort, the rates of gestational hypertension, preeclampsia, and eclampsia were the same or decreased from 37 to 43 weeks' gestation using PD, but all three increased when calculated according to OP (P<.01). CONCLUSION: We found that among complications of pregnancy that are diagnosed ante partum, use of a different denominator led to contradictory conclusions. When hypertensive disorders of pregnancy are analyzed, ongoing pregnancies should be used as the denominator.     

Appropriate maternal weight gain in singleton and twin pregnancies: what is the evidence?

The quality of the end product from andrology services continues to lack consistency and in some cases fails to meet the needs of the end users (patients or clinicians). Results of external quality assessment (EQA) schemes continue to show unacceptably wide variation for the results of a single specimen. Some laboratories are able to show that the results of semen analyses relate to both natural and assisted pregnancy and are therefore useful in the management of the infertile couple, whereas others claim that their value is limited to the identification of severe male factor infertility. With wide variation in standardisation of methodology, levels of staff training and quality assurance, it is entirely understandable that such discrepancies persist. The following article proposes that Quality Assurance (QA) is derived from standardisation of methods and implementation of good practice for the entire analytical process, i.e. from the collection and delivery of the specimen, through analysis and processing, to the eventual reporting and interpretation of the result to the clinician. Without appropriate QA, the value of diagnostic testing will remain limited and will vary according to the individual or individual laboratory performing the test.     

Velamentous cord insertion in dichorionic and monochorionic twin pregnancies – Does it make a difference?

ObjectiveTo estimate the prevalence of velamentous cord insertion (VCI) in dichorionic (DC) and monochorionic (MC) twins with and without twin-twin transfusion syndrome (TTTS), and to study the associated outcomes.MethodsWe recorded the type of umbilical cord insertion in all consecutive DC and MC placentas examined in two European tertiary medical centers. The association between VCI and perinatal outcomes was estimated and compared.ResultsA total of 1498 twin placentas were included in this study (DC placentas n = 550, MC placentas without TTTS n = 513 and MC placentas with TTTS n = 435). The prevalence of VCI in DC, MC without TTTS and MC with TTTS groups was 7.6%, 34.7% and 36.1%, respectively (P < 0.001). In MC twins (non-TTTS and TTTS groups), VCI was associated with severe birth weight discordance (odds ratio [OR] 4.76 95% CI 2.43, 10.47 and OR 4.52 95% CI 1.30, 28.59, respectively). In MC twins without TTTS, VCI was associated with small for gestational age (OR 1.66, 95% CI 1.12, 2.50). VCI was significantly associated with increased risk of intrauterine fetal demise in MC twins, and this effect was greater in the non-TTTS group (OR 2.71 95% CI 1.38, 5.47). These associations did not occur in DC group. Gestational age at birth was lower in the presence of VCI in the DC and MC twins without TTTS.ConclusionOur findings confirm that the prevalence of VCI is higher in MC twins than in DC twin pregnancies. VCI is an important indicator of adverse perinatal outcome, particularly in MC twins.     

Glycemic control in twin pregnancies with gestational diabetes: are we improving or worsening outcomes?

Objective: To estimate the association between glycemic control and adverse outcomes in twin pregnancies with gestational diabetes (GDM).

Study design: A cohort of patients with twin pregnancies and GDM were identified from one maternal–fetal medicine practice from 2005 to 2014. Patients with prepregnancy diabetes were excluded. First, outcomes were compared between patients with GDMA1 and GDMA2 (gestational age at delivery, birthweight, small for gestational age (SGA, birthweight <10th percentile), preeclampsia, and cesarean delivery). Then, finger stick glucose logs were reviewed and correlated with the risk of SGA and preeclampsia. Abnormal finger stick values were defined as: fasting ≥90?mg/dL, 1-h postprandial ≥140?mg/dL, 2-h postprandial ≥120?mg/dL.

Results: Sixty-six patients with twin pregnancies and GDM were identified (incidence 9.1%). Comparing the 43 patients with GDMA1 to the 23 patients with GDMA2, outcomes were similar, aside from patients with GDMA1 having lower birthweight of the smaller twin (2184?±?519?g versus 2438?±?428?g, p?=?0.040). The risk of preeclampsia was not associated with glycemic control. Patients with SGA had lower mean fasting values (83.3?±?5.5 versus 87.2?±?7.7?mg/dL, p?=?0.033), and a lower percentage of abnormal fasting values (24.0% versus 36.9%, p?=?0.040), abnormal post-breakfast values (9.9% versus 27.1%, p?=?0.003), and total abnormal values (20.1% versus 27.7%, p?=?0.055).

Conclusion: In twin pregnancies with GDM, improved glycemic control is not associated with improved outcomes, and is associated with a higher risk of SGA. Prospective trials in twin pregnancies should be performed to establish goals for glycemic control in twin pregnancies.     

Does chorionicity or zygosity predict adverse perinatal outcomes in twins?

OBJECTIVE: The purpose of this study was to evaluate chorionicity and zygosity as risk factors for adverse perinatal outcomes in twins. STUDY DESIGN: A population-based, retrospective cohort study was conducted of all twin deliveries in Nova Scotia, Canada, from 1988 to 1997. Chorionicity was established by histologic examination. Zygosity was determined by chorionicity, sex, and infant blood group. Three groups were established: monochorionic/monozygotic twins, dichorionic/dizygotic twins, and dichorionic/majority monozygotic twins. RESULTS: Outcomes from 1008 twin pregnancies were analyzed. Monochorionic/monozygotic twins had lower mean birth weights compared with dichorionic/dizygotic twins. Rates of perinatal mortality of at least 1 twin were significantly higher among monochorionic/monozygotic twins relative to dichorionic/dizygotic twins (relative risk, 2.5; 95% CI, 1.1-2.5). Dichorionic/majority monozygotic twins had similar perinatal outcomes compared with dichorionic/dizygotic twins. CONCLUSION: Monochorionicity increases the risk of adverse perinatal outcome, whereas the effect of zygosity is less clear. Because chorionicity can be determined by prenatal ultrasound scanning, this information should be considered in the prenatal care of twin pregnancies.