BACKGROUND AND PURPOSE:

• Di Masco et al. (Ultrasound in Obstetrics & Gynecology, 2020) assessed the rate of fetal loss following amniocentesis or CVS in twin pregnancy

METHODS:

• Systematic review and meta-analysis
• Data sources
  • MEDLINE, EMBASE and Cochrane databases
• Inclusion criteria
  • Prospective and retrospective studies that reported procedure-related complications following amniocentesis or CVS in twin pregnancy
• Data analysis
  • Head-to-head meta-analyses to directly compare each outcome between
    • Amniocentesis vs no amniocentesis
    • CVS vs no CVS
  • Pooled risk differences (RD) computed between exposed (invasive testing) and unexposed
• Primary outcome
  • Rate of procedure-related fetal loss
• Secondary outcomes
  • Fetal loss occurring <24 weeks of gestation
  • Fetal loss occurring within 4 weeks of the procedure

RESULTS:

• 16 studies
  • Invasive procedure: 3419 twin pregnancies
  • Control (no invasive procedure): 2517 twin pregnancies

Amniocentesis

• There was a higher risk for overall fetal loss in those undergoing amniocentesis in twins (P = 0.04)
  • Odds ratio (OR) 1.46 | RD 0.013
• No differences were found for the following
  • Fetal loss <24 weeks
    • OR 1.59 (P = 0.06) | RD 0.010 (P = 0.11)
  • Fetal loss within 4 weeks after the procedure
    • OR 1.38 (P = 0.3) | RD 0.003 (P = 0.8)
  • Pooled rate of fetal loss
    • Amniocentesis: 2.4% (95% CI, 1.4 to 3.6%)
    • Control: 2.4% (95% CI, 0.9 to 4.6%)

Chorionic villus sampling

• No differences were found for the following
  • Fetal loss
    • OR 1.61 (P = 0.5) | RD 0.003 (P = 0.8)
  • Fetal loss <24 weeks of gestation
    • OR 1.61 (P = 0.5) | RD 0.003 (P = 0.8)
• Pooled rate of fetal loss
  • CVS: 2.0% (95% CI, 0.0 to 6.5%)
  • Control: 1.8% (95% CI, 0.3 to 4.2%)

CONCLUSION:

• The risk of fetal loss following invasive sampling procedures in twin pregnancies is not as high as previously reported
• The rate of fetal loss before 24 weeks and within 4 weeks of the procedure was not different than the background (control) risk
• The authors conclude

These data are intuitively helpful when counseling parents about the safety of the procedure, as the woman can be reassured that the overall risk of fetal loss is low

Learn More – Primary Sources:

Risk of fetal loss following amniocentesis or chorionic villus sampling in twin pregnancy: systematic review and meta‐analysis

Related ObG Topics:

Should Amniocentesis or Chorionic Villus Sampling Be Offered to All Pregnant Women?

Does Noninvasive Screening Result in Fewer Miscarriages When Compared to Amniocentesis?

Do Amniocentesis or CVS Really Lead to Increased Risk of Miscarriage? 

Does Single or Double Needle Insertion in Twin Amniocentesis Influence Complication Risk?