Multifetal pregnancy reduction

Quadruplet pregnancy outcome with and without fetal reduction: Danish national cohort study (2008-2018) and comparison with dichorionic twins

OBJECTIVES

To perform a nationwide study of quadrichorionic quadriamniotic (QCQA) quadruplet pregnancies and to compare the pregnancy outcome in those undergoing fetal reduction with non-reduced quadruplets and dichorionic diamniotic (DCDA) twin pregnancies from the same time period.

METHODS

This was a retrospective Danish national register-based study performed using data from the national Danish Fetal Medicine Database, which included all QCQA quadruplets and all non-reduced DCDA twin pregnancies with an estimated due date between 2008 and 2018. The primary outcome measure was a composite of adverse pregnancy outcomes, including pregnancy loss or intrauterine death of one or more fetuses. Secondary outcomes included gestational age at delivery, the number of liveborn children, preterm delivery before 28, 32 and 37 gestational weeks and birth weight. Data on pregnancy complications and baseline characteristics were also recorded. Outcomes were compared between reduced and non-reduced quadruplet pregnancies, and between DCDA pregnancies and quadruplet pregnancies reduced to twins. A systematic literature search was performed to describe and compare previous results with our findings.

RESULTS

Included in the study were 33 QCQA quadruplet pregnancies, including three (9.1%) non-reduced pregnancies, 28 (84.8%) that were reduced to twin pregnancy and fewer than three (6.1%) that were reduced to singleton pregnancy, as well as 9563 DCDA twin pregnancies. Overall, the rate of adverse pregnancy outcome was highest in non-reduced quadruplets (66.7%); it was 50% in quadruplets reduced to singletons and 10.7% in quadruplets reduced to twins. The proportion of liveborn infants overall was 91.1% of the total number expected to be liveborn in quadruplet pregnancies reduced to twins. This was statistically significantly different from 97.6% in non-reduced dichorionic twins (P = 0.004), and considerably higher than 58.3% in non-reduced quadruplets. The rates of preterm delivery < 28, < 32 and < 37 weeks were decreased in quadruplets reduced to twins compared with those in non-reduced quadruplet pregnancies. Quadruplets reduced to twins did not achieve equivalent pregnancy outcomes to those of DCDA twins.

CONCLUSION

This national study of QCQA quadruplets has shown that multifetal pregnancy reduction improves pregnancy outcome, including a decreased rate of preterm delivery and higher proportion of liveborn children. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Selective reduction in twins and multiple pregnancies

The number of multiple pregnancies has increased, mainly due to the uncontrolled use of the assisted conception techniques. Multifetal pregnancy reduction (MFPR) has been used to reduce the risks associated with these high-risk pregnancies. It is performed in the first trimester of pregnancy by transabdominal injection of potassium chloride into the fetal heart. The risk of miscarriage seems to be associated with the final number of fetuses. A review of the literature suggests that MFPR results in better pregnancy outcome, regardless of the initial number of fetuses. The reduction to a lower number of fetuses reduces fetal losses, prematurity, infant mortality and morbidity.

Contemporary outcomes with the latest 1000 cases of multifetal pregnancy reduction (MPR)

OBJECTIVE

This study was undertaken to report on the outcome of multifetal pregnancy reduction in the most up-to-date largest single center experience with this procedure, and compare the outcome to the first 1000 cases performed at the same institution.

STUDY DESIGN

1000 consecutive cases of multifetal pregnancy reduction performed at the Mount Sinai Medical Center between the years 1999-2006 were identified. Pregnancy outcomes were retrieved from a large database as well as chart review. Differences in means and proportions were evaluated by analysis of variance, chi-square, Cochran-Armitage test for trend or 2-tailed Fisher exact test as appropriate.

RESULTS

Outcomes were available on 841 cases, for a follow-up rate of 84.1%; 95.2% of patients delivered after 24 weeks, for a complete loss rate of 4.7%. There was a significant trend toward decreasing loss rates with decreasing starting numbers. Mean gestational age at delivery was later, and birthweights greater, for reduction to singletons vs twins.

CONCLUSION

Loss rates after multifetal pregnancy reduction have remained stable at 4.7%. The lowest loss rate occurred in the patients reducing from twins to a singleton (2.1%). Reduction to a singleton was also associated with higher birthweights and lower rates of preterm deliveries.

Pregnancy outcomes of different methods for multifetal pregnancy reduction: a comparative study

The purpose of this study was to evaluate the outcomes of various methods of multifetal pregnancy reduction (MFPR) and to determine which method produces better outcomes. One hundred and forty-eight patients with multiple pregnancies resulting from assisted reproduction programs and underwent MFPR were included. According to the use of potassium chloride (KCl), patients were divided into 'KCl', and 'non- KCl' groups, and based on gestational age at the time of procedures, patients were divided into 'Early' (before 8 weeks of gestation) and 'Late' (at 8 weeks or later) groups. Firstly, to clarify the effect of each component of MFPR procedure, data were analyzed between 'KCl' and 'non-KCl' groups, and between 'Early' and 'Late' groups with adjustments. Secondly, comparison between 'Early, non-KCl' and 'Late, KCl' groups was performed to evaluate the combinative effect of both components. Non-KCl groups showed a significantly higher take-home-baby rate, and lower risk of extreme prematurity and preterm premature rupture of membranes (PPROM) than KCl groups. Early groups showed a lower immediate loss rate than Late groups. As compared with 'Late, KCl' group, 'Early, non-KCl' group was superior in terms of immediate loss, pregnancy loss, take-home-baby, and PPROM rates. Our data suggest that the 'early, non-KCl' method may be a better option for MFPR.

Cervical length, multifetal pregnancy reduction, and prediction of preterm birth

PURPOSE

To evaluate the application of transvaginal sonography assessment of cervical length before fetal reduction for predicting spontaneous preterm birth in triplet gestations reduced to twins.

METHODS

This retrospective study was conducted at the ultrasound unit of a university-affiliated municipal hospital. The study cohort consisted of 25 women with triplet gestations following ovulation induction or assisted-reproduction techniques who underwent fetal reduction to twins. Cervical length was assessed via transvaginal sonography before fetal reduction, and data on pregnancy outcome were retrieved from maternal records and/or maternal interviews.

RESULTS

Cervical length (mean +/- SD) at reduction was 4.0 +/- 0.85 (range: 1.2-5.5). Five women were excluded from statistical evaluation because pregnancy complications precluded spontaneous delivery. Two of 3 (67%) women with a cervical length of <3.5 cm delivered prior to 33 weeks' gestation compared with 1/17 (6%) women with a cervical length > or = 3.5 cm. This difference was statistically significant (P < 0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of cervical lengths <3.5 cm to predict delivery prior to 33 gestational weeks was 67%, 94%, 67%, and 94%, respectively.

CONCLUSIONS

Measurement of cervical length in triplet pregnancies before fetal reduction provides useful predictive information on the risk for preterm delivery.

Invasive procedures in multifetal pregnancies

This review discusses the various invasive techniques currently performed in multiple pregnancies.

Targeted first-trimester prenatal diagnosis before fetal reduction in triplet gestations and subsequent outcome

OBJECTIVE

To assess the feasibility of targeted first-trimester ultrasound evaluation in triplet gestations and to report the outcome in reduced and expectantly managed triplets.

METHODS

This was a retrospective analysis of 127 triplets at 11-14 weeks with targeted ultrasound examination including nuchal translucency (NT) screening.

RESULTS

One or more abnormal findings were observed in 33 of 381 fetuses (8.7%), including increased NT (n = 18), malformations (n = 4), aneuploidy (n = 3), relative intrauterine growth restriction (n = 2) or spontaneous demise (n = 13). Of 63 patients (49%) who chose reduction, selective termination due to abnormal findings was performed in 13 fetuses. The rates of complete abortion <24 weeks were 9.8% and 3.2% for those with expectant management and fetal reduction, respectively. Expectantly managed triplets delivered significantly earlier (31.1 +/- 3.8 vs. 35.6 +/- 3.3 weeks) (P < 0.01) with a lower mean birth weight (1483 +/- 552 g vs. 2305 +/- 557 g) (P < 0.01) and a lower number of liveborn fetuses (85.6% vs. 97.4%) (P < 0.01) than those reduced.

CONCLUSION

Targeted first-trimester ultrasound is feasible and reliable in triplet gestations and should be an integral part of the counseling process. It results in more accurate selection for those who consider fetal reduction. Our data further support fetal reduction as a valuable strategy to improve perinatal outcome in triplet pregnancies.

Multifetal pregnancy reduction and selective termination

MPR and ST are important options for patients who have multifetal pregnancies. Both procedures have been shown to be technically safe and result in acceptable pregnancy loss rates and GAs at delivery. An important caveat is that these findings are observed in centers that have vast experience performing this type of procedure and should not be generalized to all centers. The authors believe that the good outcomes reported here and elsewhere are a result of having a relatively limited number of operators adhering to a strict common protocol and that they should not be generalized to all centers. Awareness of the ethical and psychological issues aids counseling of patients and their follow-up, but more information is needed in this area. Finally, it is the authors' hope that advances in ART will decrease the need for MPR procedures in the future.

Invasive procedures in multiple gestations

PURPOSE OF REVIEW

The incidence of multiple gestations has increased significantly with advances in assisted reproductive techniques resulting in a concomitant increase in invasive procedures in these pregnancies. Commonly performed invasive procedures include amniocentesis, chorionic villus sampling, multifetal pregnancy reduction, and selective termination. Amniocentesis and chorionic villus sampling are also performed in singleton pregnancies, while multifetal pregnancy reduction and selective termination are procedures that are unique to multiple gestations.

RECENT FINDINGS

With increased operator experience, pregnancy loss rates after chorionic villus sampling, multifetal pregnancy reduction, and selective termination have decreased to acceptably low levels. Amniocentesis and chorionic villus sampling continue to have similar loss rates in experienced hands. A recent study suggests that amniocentesis in twins may have a higher post-procedural loss rate than in singletons; this may be due to the higher background loss rate of twins. There has been a recent increase in multifetal pregnancy reduction to a singleton with a trend towards improved outcomes over reduction to twins; future studies should focus on whether this confers a definitive advantage. Newer data suggests that selective termination after 20 weeks gestation in experienced hands does not increase loss rates over those procedures performed before 20 weeks. Newer techniques, such as cord coagulation, continue to be developed for selective termination in monochorionic pregnancies, though still with considerable morbidity and mortality.

SUMMARY

In summary, invasive procedures in multiple gestations are now commonly performed with. It is our hope that primary prevention of high order multiple pregnancies by optimization of assisted reproductive techniques will decrease the need for these procedures.

A single center experience with 1000 consecutive cases of multifetal pregnancy reduction

OBJECTIVE

Multifetal pregnancy reduction (MPR) is a technique developed to reduce the risks of a multifetal pregnancy. The objective of this article was to report the outcome of MPR in the largest single-center experience to date.

STUDY DESIGN

A computerized database was used to determine the outcome of 1000 consecutive cases patients undergoing transabdominal MPR between the years 1986 and 1999. Outcomes analyzed included pregnancy loss rates, preterm delivery rates, and mean birth weights.

RESULTS

The complete pregnancy loss rate was 5.9%, whereas the unintended pregnancy loss rate was 5.4%. The loss rate was 9.5% in the first 200 cases and remained stable at 4.5% to 6.0% over the next 800 cases. The loss rate was lowest with starting numbers of two fetuses (2.5%), remained stable for three, four, and five fetuses, and increased to 12.9% with starting numbers of six fetuses or greater. Loss rates were similar with a finishing number of one or two (3.5 % and 5.5%, respectively) but were highest for a finishing number of three (16.7%). Analysis of birth weights showed a linear decline with increasing starting and finishing numbers. Mean gestational age of delivery for finishing numbers of one, two, and three fetuses was 37.9, 35.3, and 33.5 weeks.

CONCLUSION

Unintended loss rates associated with MPR have stabilized at 5.4%. Loss rates are highest with starting numbers of six or more fetuses, but did not differ for starting numbers of three, four, or five fetuses. Gestational age of delivery for finishing numbers of one, two, and three fetuses are similar to that of nonreduced pregnancies.

Hospitalization vs. outpatient care in the management of triplet gestations

OBJECTIVE

To compare the course and outcome of triplet gestations under a preventive care strategy that includes hospitalization, surveillance, bed rest, and daily specialized care from the beginning of the second trimester, with pregnancies managed according to the Croatian standard outpatient care protocol for multiplets.

METHODS

A retrospective study of 79 triplet pregnancies. Preventive hospitalization from the beginning of the second trimester, with complete bed rest and all necessary interventions, was chosen by 55 women (Group I). The remaining 24 women (Group II) elected the standard outpatient protocol for multiple pregnancies. Outpatient management with prophylactic bed rest was initiated at home as soon as the multiple pregnancy was diagnosed. After 28 weeks of gestation, all outpatients were hospitalized until delivery irrespective of symptoms.

RESULTS

There was no difference between the groups regarding maternal age, race, pre-pregnancy weight and height, weight gain during the first 24 weeks of pregnancy, or the proportion of pregnancies achieved with assisted reproductive technology. Four out of 55 women (7.2%) from Group I and 4 out of 24 women (12.5%) from Group II had monochorionic triplet pregnancies (P=n.s.). Nulliparity was more frequent in Group I than in Group II (P=0.006). Elective cesarean delivery was significantly more frequent in Group I (46 out of 55 gestations, 72.7%) than in Group II (9 out of 24 gestations, 37.5%), P=0.024. Gestational age at delivery and mean birth weight were significantly higher in Group I than in Group II (P<0.001). Deliveries up to 28 weeks of pregnancy were infrequent in Group I (P=0.02). Thirty-three gestations in Group I (60%) and 6 (25%) in Group II had a duration of 33-36 weeks (P<0.001). Two out of 55 triplet gestations in Group I (3.6%) and 4 out of 24 in Group II (16.7%) ended in spontaneous abortion (P=0.053). The survival of the three triplets was more frequent in Group I than in Group II (P=0.048). For gestations reaching 24 weeks or more, the fetal and perinatal death rate was significantly lower in Group I (P<0.001). In Group I the intrauterine death rate for fetuses weighing 1500 g or less was also significantly lower (P=0.007), and the early neonatal death rate was almost half (15.8 vs. 28.9%, P=0.157). There were no differences in other pregnancy complications between the two groups except significantly more frequent preterm premature rupture of membranes and preterm labor requiring parenteral tocolysis in Group II (P=0.042 and 0.036, respectively), and significantly more frequent fetal growth retardation in Group I (P<0.001).

CONCLUSION

Preventive hospitalization offers a better outcome for triplets even though prolonged hospitalization and all other procedures necessary to achieve optimal pregnancy outcome are also offered in the Croatian standard outpatient care protocol for multiplet pregnancies.