Invasive diagnostic procedures in twin pregnancies

The risk factors of procedure-related complications after amniocentesis in twin pregnancies: a retrospective analysis

BACKGROUND

There is an increasing demand for prenatal diagnostic testing in twin pregnancies, however, anecdotally there is a higher incidence of procedure-related complications after amniocentesis than that in singleton pregnancies. There is a paucity of data regarding risk factors of amniocentesis in twin pregnancies.

METHODS

Women with twin pregnancies who underwent amniocentesis between January 2016 and December 2020 were enrolled in this retrospective study. Procedure-related complications including spontaneous miscarriage, intrauterine fetal death, spontaneous preterm delivery, preterm premature rupture of membranes, and placental abruption in one or both fetuses after amniocentesis were assessed. Meanwhile, potential risk factors related to amniocentesis including chorionicity, gestational age, conception, number of needle insertions, parity, history of miscarriage, indications, and pregnancy-related complications (pregnancy-induced hypertension and gestational diabetes) were also recorded.

RESULTS

A total of 811 women with twin pregnancies underwent amniocentesis were included, with a procedure-related complications rate of 3.83%. Risk factors associated with increased risk of procedure-related complications after amniocentesis in twin pregnancies were chorionicity (adjusted odds ratio [aOR]: 4.06), gestational age at the procedure (aOR: 2.76), and numbers of needle insertions (aOR: 3.26). In the monochorionic twin pregnancy, hemorrhage during this pregnancy (aOR: 12.01), polyhydramnios (aOR: 5.03), and numbers of needle insertions (aOR: 3.15) were risk factors after amniocentesis. In the dichorionic twin pregnancy, gestational age at the procedure (OR:4.47) affected the risk of procedure-related complications after amniocentesis. In the subgroup of gestational age at the procedure ≤ 24+ 0 weeks, risk factors associated with increased risk of procedure-related complications after amniocentesis in twin pregnancies were chorionicity (aOR: 5.14), and numbers of needle insertions (aOR: 3.76).

CONCLUSION

The procedure-related complications rate is 3.83% in our institution during the study period. The present study has emphasized the significance of certain risk factors for adverse outcome and will be useful in counseling patients with twin pregnancies.

Clinical Practice Guidelines for Prenatal Aneuploidy Screening and Diagnostic Testing from Korean Society of Maternal-Fetal Medicine: (2) Invasive Diagnostic Testing for Fetal Chromosomal Abnormalities

The Korean Society of Maternal Fetal Medicine proposed the first Korean guideline on prenatal aneuploidy screening and diagnostic testing, in April 2019. The clinical practice guideline (CPG) was developed for Korean women using an adaptation process based on good-quality practice guidelines, previously developed in other countries, on prenatal screening and invasive diagnostic testing for fetal chromosome abnormalities. We reviewed current guidelines and developed a Korean CPG on invasive diagnostic testing for fetal chromosome abnormalities according to the adaptation process. Recommendations for selected 11 key questions are: 1) Considering the increased risk of fetal loss in invasive prenatal diagnostic testing for fetal genetic disorders, it is not recommended for all pregnant women aged over 35 years. 2) Because early amniocentesis performed before 14 weeks of pregnancy increases the risk of fetal loss and malformation, chorionic villus sampling (CVS) is recommended for pregnant women who will undergo invasive prenatal diagnostic testing for fetal genetic disorders in the first trimester of pregnancy. However, CVS before 9 weeks of pregnancy also increases the risk of fetal loss and deformity. Thus, CVS is recommended after 9 weeks of pregnancy. 3) Amniocentesis is recommended to distinguish true fetal mosaicism from confined placental mosaicism. 4) Anti-immunoglobulin should be administered within 72 hours after the invasive diagnostic testing. 5) Since there is a high risk of vertical transmission, an invasive prenatal diagnostic testing is recommended according to the clinician's discretion with consideration of the condition of the pregnant woman. 6) The use of antibiotics is not recommended before or after an invasive diagnostic testing. 7) The chromosomal microarray test as an alternative to the conventional cytogenetic test is not recommended for all pregnant women who will undergo an invasive diagnostic testing. 8) Amniocentesis before 14 weeks of gestation is not recommended because it increases the risk of fetal loss and malformation. 9) CVS before 9 weeks of gestation is not recommended because it increases the risk of fetal loss and malformation. 10) Although the risk of fetal loss associated with invasive prenatal diagnostic testing (amniocentesis and CVS) may vary based on the proficiency of the operator, the risk of fetal loss due to invasive prenatal diagnostic testing is higher in twin pregnancies than in singleton pregnancies. 11) When a monochorionic twin is identified in early pregnancy and the growth and structure of both fetuses are consistent, an invasive prenatal diagnostic testing can be performed on one fetus alone. However, an invasive prenatal diagnostic testing is recommended for each fetus in cases of pregnancy conceived via in vitro fertilization, or in cases in which the growth of both fetuses differs, or in those in which at least one fetus has a structural abnormality. The guidelines were established and approved by the Korean Academy of Medical Sciences. This guideline is revised and presented every 5 years.

Obstetrical outcomes after first-trimester chorionic villus sampling in twin pregnancies: A retrospective case-control study

AIM

Prenatal diagnostic testing by chorionic villus sampling (CVS) is sometimes recommended for women with twin pregnancies. However, few studies have compared the outcomes between twins with CVS and control twins without intervention. This study aimed to compare the obstetrical outcomes of CVS in twin pregnancies and those in non-intervention twin pregnancies.

METHODS

First-trimester transabdominal CVS was performed on dichorionic-diamniotic twins (n = 54; Group 1) between December 2006 and January 2017 at the Department of Obstetrics and Gynecology at our hospital, and the data were retrospectively analyzed. CVS risks were evaluated by comparing obstetrical outcomes with those of a control population of 155 dichorionic-diamniotic twins without intervention (Group 2).

RESULTS

The difference in the overall fetal loss rate (Group 1, 7.4% vs Group 2, 3.9%; P = 0.287) between the two groups was not statistically significant. The miscarriage rate, defined as delivery at <24 gestational weeks, and early preterm delivery, defined as delivery at <34 gestational weeks, were not significant between the groups (miscarriage: Group 1, 5.6% vs Group 2, 3.2%; P = 0.428; early preterm delivery: Group 1, 11.1% vs Group 2, 9.0%; P = 0.788). The mean gestational age at delivery, birth weights and neonatal intensive care unit admission rate were not statistically significant between the groups. Thus, the overall fetal loss rate and obstetrical outcomes of Group 1 were comparable with those of Group 2.

CONCLUSION

In conclusion, the overall obstetrical outcomes were not significantly different between twins with CVS and control twins with the advantage of enabling early decision-making about selective feticide in twins with CVS.

Single or double needle insertion in twin's amniocentesis: Does the technique influence the risk of complications?

OBJECTIVE

To compare complication rates following amniocentesis in twin gestations, according to sampling technique and number of needle insertions.

STUDY DESIGN

A retrospective cohort study of all women with twin gestations who underwent amniocentesis and delivered in a single university affiliated medical center during 2002-2016. Amniocentesis was performed either through one uterine entry with passage through the inter-twin membrane or through two different entries to the two amniotic sacs. Pregnancy outcome of women that underwent single needle insertion amniocentesis, was compared to this of double needle insertion. Primary outcome was neonatal complications within 4 weeks after amniocentesis (late abortion, chorioamnionitis, preterm premature rupture of membranes, or hospitalization due to related symptoms). Secondary outcomes were gestational week at delivery and labor characteristics.

RESULTS

The study group comprised 212 women. Of them, 73 (34.4%) underwent a single uterine insertion and 139 (65.6%) two separate needle insertions. Baseline characteristics did not differ between the groups. The amniocentesis complication rate was 13.7% in the single insertion group and 16.5% in the double insertion group (p = 0.587). Multivariate analysis found that a single insertion method had no statistically significant influence on complication rate, after making adjustments for potential confounders (OR = 1.085, 95% CI 0.4-2.9; p = 0.871). Other labor characteristics were similar between the groups.

CONCLUSION

Needle insertion technique in twin gestation amniocentesis was not associated with procedure related complications.

Obstetrical Outcomes of Amniocentesis or Chorionic Villus Sampling in Dichorionic Twin Pregnancies

BACKGROUND

Under certain situations, women with twin pregnancies may be counseled to undergo invasive prenatal diagnostic testing. Chorionic villus sampling and amniocentesis are the two generally performed invasive prenatal diagnostic tests. Studies comparing procedure-related fetal loss between first-trimester chorionic villus sampling and second-trimester amniocentesis in twin pregnancies are limited. This study aimed to evaluate the procedure-related fetal loss and the obstetrical outcomes of these two procedures, chorionic villus sampling and amniocentesis in twin pregnancies.

METHODS

The data from dichorionic-diamniotic twin pregnancies on which first-trimester chorionic villus sampling (n = 54) or second-trimester amniocentesis (n = 170) was performed between December 2006 and January 2017 in a single center were retrospectively analyzed. The procedure-related fetal loss was classified as loss of one or all fetuses within 4 weeks of procedure, and overall fetal loss was classified as loss of one or all fetuses during the gestation. The groups were compared with respect to the procedure-related and obstetrical outcomes.

RESULTS

The difference in proportion of procedure-related fetal loss rate (1.9% for chorionic villus sampling vs. 1.8% for amniocentesis; P = 1.000) and the overall fetal loss rate (7.4% for chorionic villus sampling vs. 4.7% for amniocentesis; P = 0.489) between the two groups was not significant. The mean gestational ages at delivery were not statistically significant.

CONCLUSION

Both the overall fetal loss rate and the procedure-related fetal loss rate of chorionic villus sampling and amniocentesis in dichorionic twin pregnancies had no statistical significance. Both procedures can be safely used individually.

Prenatal screening and diagnosis of aneuploidy in multiple pregnancies

Prenatal screening for aneuploidy has changed significantly over the last 30 years, from being age-based to maternal serum and ultrasound based techniques. Multiple pregnancies present particular challenges with regards to screening as serum-based screening techniques are influenced by all feti while ultrasound-based techniques can be fetus specific. Tests currently available tend to not perform as well in multiple compared to singleton pregnancies. Considerations must be given to these variations when discussing and performing screening for aneuploidy in this situation. Prenatal invasive diagnosis techniques in multiple pregnancies bring their own challenges from a technical and counselling point of view, in particular with regards to sampling error, mapping and assignment of results and management of abnormal results. This review addresses these particular challenges and provides information to facilitate care.

Survey of prenatal counselling practices regarding aneuploidy risk modification, invasive diagnostic procedure risks, and procedure eligibility criteria in Canadian centres

OBJECTIVE

To explore prenatal practices related to aneuploidy screening, risk modification, and invasive diagnostic procedures across Canadian centres.

METHODS

We conducted a survey of members of the Canadian Association of Genetic Counsellors, the Canadian College of Medical Genetics, and the Canadian Society of Maternal Fetal Medicine, who provide direct counselling or management of prenatal patients in Canada.

RESULTS

Eighty-two of 157 respondents indicated that their centre's definition of advanced maternal age was ≥ 35 years, with 33/157 respondents reporting an advanced maternal age definition of ≥ 40 years. The majority of respondents reported that prenatal serum screening for aneuploidy is provincially funded in their province or territory (121/147). The majority of respondents who reported that prenatal screening is not provincially funded (17/147) were from Quebec (14/17). Thirty-nine of 123 respondents reported that their centre defines increased nuchal translucency as ≥ 3.0 mm, whereas 49/123 reported a definition of ≥ 3.5 mm. Sixty-four of 150 respondents reported that the aneuploidy risk provided by serum screening is modified by a soft marker likelihood ratio, whereas 46/150 respondents reported that both age-related and serum screening risks are modified. Fifty-nine of 124 respondents reported that their centre will modify aneuploidy risk after a normal ultrasound; the most commonly cited negative likelihood ratio was 0.5. The most commonly reported procedure-related risk for chorionic villus sampling was 1/100 (123/147) and for amniocentesis was 1/200 (73/142).

CONCLUSION

This study demonstrates inconsistencies in prenatal practices and access to screening programs across Canada. The information gained from this study will inform policy advisors developing prenatal practice guidelines at both the provincial and national levels.

Twin pregnancies complicated by a single malformed fetus: chorionicity, outcome and management

The objective of this study was to evaluate the impact of one abnormal fetus in a twin pregnancy, to compare impact of chorionicity and clinical outcome of intervention and expectant management. Thirty-seven dichorionic (DC) twins and 18 monochorionic (MC) twins complicated with one malformed fetus were evaluated for gestational age, birthweight and perinatal outcome. Six hundred and forty-two twin pregnancies were evaluated in the database. The control groups consisted of 429 DC and 86 MC twins without anomalous fetus. Mean birthweight and gestational age at birth for DC control group were (n = 429; 2137g and 34.71 weeks), DC study group, n = 37; 2117g (p = .338) and 33.97 weeks (p = .311), and DC study group with major malformations, n = 30; 2019g (p = .289) and 33.3 weeks (p = .01), and showed only significance for gestational age. There was no statistical significance between MC control group, n = 86; 2097g and 34.93 weeks, and MC study group, n = 18; 2237g (p = .338), and 34.42 weeks (p = .502). Because of limited data, the preliminary evaluation for expectant management and intervention, and survival of at least one normal fetus showed no impact. We conclude that, although, all DC twin pregnancies have a risk for preterm delivery, DC twins complicated with major malformation of one twin, have a lower mean gestational age at birth. Preliminary results for intervention does not improve fetal outcome for DC and MC twins and needs further evaluation with greater studies of impact or review.

Amniocentesis and chorionic villus sampling in twin gestations: which is the best sampling technique?

OBJECTIVE

To compare the fetal loss rate <24 weeks and the preterm premature rupture of the membranes <34 weeks' gestation according to type of invasive procedure and to sampling techniques in twins.

STUDY DESIGN

Retrospective cohort study of 204 twin pregnancies, who underwent amniocentesis (100) or chorionic villus sampling (104).

RESULTS

Fetal loss rate <4 weeks was 3.85% in chorionic villus sampling group and 4.00% in amniocentesis group (P value not significant). According to sampling technique, fetal loss rate was 4.17% (chorionic villus sampling 1 puncture), 2.70% (amniocentesis 1 puncture), 3.75% (chorionic villus sampling 2 punctures), and 4.76% (amniocentesis 2 punctures), (P values not significant). Preterm premature rupture of the membranes rate <34 weeks was 8.2% chorionic villus sampling group and 10% in amniocentesis group (P value not significant). According to sampling technique, preterm premature rupture of the membranes rate was 12.5% (chorionic villus sampling 1 puncture), 8.1% (amniocentesis 1 puncture), 6.9% (chorionic villus sampling 2 punctures), and 11.1 % (amniocentesis 2 punctures), (P values not significant).

CONCLUSION

Double entry technique does not affect significantly the outcomes evaluated, in both amniocentesis and chorionic villus sampling.

Cordocentesis in multifetal pregnancies

OBJECTIVE

To describe the experiences in diagnostic cordocentesis in twin pregnancies at midpregnancy

METHODS

The database and medical records of pregnant women attending Maternal Fetal Medicine Unit of the hospital for diagnostic cordocentesis at midpregnancy between January 1989 and September 2006 were retrospectively reviewed.

RESULTS

During 17 years of experience, 4,241 cordocenteses at midpregnancy were performed for prenatal diagnosis, including 59 procedures in 30 multiple pregnancies (29 twins and 1 triplet). The mean gestational age at the time of cordocentesis was 19.5 +/- 1.6 weeks. Success rate of the samplings was 98.3% with one sample was maternal blood contamination. Averaged-time used of the procedures was 8.2 minutes (range 1-45 minutes). The procedure-related complications included transient bleeding at puncture site (8.5%) and transient fetal bradycardia (22.0%). The total fetal loss rate was 10.5% but there was no cordocentesis-related fetal loss (0.0%), defined as a fetal loss within 2 weeks after the procedure.

CONCLUSION

This study may provide a new insight on the safety of cordocentesis in multifetal pregnancies at midpregnancy. The procedure-related fetal loss is not as high as reported in the past. This study suggests cordocentesis be a relatively safe and highly successful in obtaining fetal blood samples.