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

Amniocentesis in Twin Pregnancies: Risk Factors of Fetal Loss

This study aims to determine if second trimester amniocentesis in twin pregnancies provides a significant independent contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy. This was a retrospective cohort study of women with twin gestations booked for routine prenatal care in four fetal medicine units in Poland in the years 2010-2020. The study population included: (1) twin pregnancies that underwent amniocentesis at 16-20 weeks' gestation; (2) twin pregnancies that did not require any further testing and were followed-up routinely. Univariable and multivariable regression analysis was used to define which maternal and pregnancy characteristics provided a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy. In the study period, 2645 twin pregnancies were eligible for analysis. There were 144 cases of miscarriage defined as fetal loss of one or both twins before 24 weeks and 40 cases of intrauterine death of one or both twins after 24 weeks. A total number of 162 twin pregnancies underwent amniocentesis at 16-20 weeks' gestation. The rate of miscarriage before 24 weeks and the rate of fetal loss at any stage of pregnancy in the group that underwent amniocentesis was 10.49% and 13.58%, respectively, compared to 5.11% and 6.52% that did not undergo amniocentesis. Multivariable regression analysis showed that factors providing a significant independent contribution in the prediction of miscarriage and fetal loss at any stage of pregnancy were monochorionicity (MC), large intertwin discordance in crown-rump length (CRL), low Pregnancy Related Plasma Protein (PAPP-A) MoM and nuchal translucency (NT) above 95th centile. Amniocentesis in twin pregnancies does not provide a significant contribution in the prediction of miscarriage or fetal loss at any stage of pregnancy.

Pregnancy Loss After Amniocentesis with Double-Needle Insertions in Twin Pregnancies

The aim of this study was to determine the pregnancy loss rate of amniocentesis with double-needle insertions in twin pregnancies. This was a retrospective study of twin pregnancies who underwent amniocentesis with double-needle insertion between 2010 and 2019 at a single center. The pregnancy loss rates were recorded as single or double fetal loss before 24 weeks’ gestation and within 4 weeks after the procedure. Risk factors for pregnancy loss after amniocentesis were also assessed. A total of 678 twin pregnancies with amniocentesis were finally included. The pregnancy loss rates before 24 weeks’ gestation and within 4 weeks after the procedure were 0.9% and 1.9%, respectively. Only one fetal loss was presumed to be a direct result of the procedure. All other cases were complicated by structural or chromosomal anomalies. Twin pregnancies with abnormal ultrasound findings had a significantly higher rate of pregnancy loss with a relative risk of 4.81 (95% CI [1.03, 22.2]). Our study showed a low pregnancy loss rate after amniocentesis in twin pregnancies with double-needle insertions technique of sampling, which can help decision making in prenatal screening and diagnosis for twin pregnancies.

Comparisons of pregnancy outcomes between twin pregnancies with and without second-trimester amniocentesis

OBJECTIVE

To assess the amniocentesis-related pregnancy loss rate and preterm birth rate among twin pregnancies undergoing amniocentesis.

METHODS

A retrospective cohort study was conducted at a tertiary center. The study group included twin pregnancies undergoing amniocentesis during 16 to 22 weeks of gestation. The control group was those not undergoing amniocentesis. All amniocenteses were performed by the MFM specialists. The main outcomes were the rate of pregnancy loss (before 24 weeks) and preterm birth.

RESULTS

A total of 332 cases in the study group and 1188 controls were analyzed. The percentages of maternal age ≥35 years, high parity, and cases complicated with medical diseases were significantly higher in the study group. The pregnancy loss rate after the procedure tended to be higher, but not significant, in the study group (3.0% vs 2.2% P = .383). Likewise, the rate of preterm birth in the study group was higher, but not significant (70.5% vs 66.0% P = .130). Logistic regression analysis to adjust confounding factors showed no significance of amniocentesis on pregnancy loss and preterm birth.

CONCLUSION

Though amniocentesis in twin pregnancies has theoretical risk of pregnancy loss, it is relatively safe when performed by maternal-fetal medicine specialists. This information is useful for counseling, especially when performed by experienced hands.