Effect of selective second-trimester multifetal pregnancy reduction and its timing on pregnancy outcome

Objective: To investigate the impact of multifetal pregnancy reduction (MFPR) on the progress and outcome of pregnancy, we compared the outcomes of this procedure performed at different stages of gestation. Methods: 302 consecutive patients admitted to the Department of Obstetrics and Gynecology of Provincial Hospital Affiliated to Shandong University from January, 2002, to February 2012 with multifetal pregnancies were included. All pregnancies were induced by assisted reproductive technology. 152 multifetal pregnancies (triplets or quadruplets) were reduced to twin pregnancies (RT) and 150 non-reduced twin pregnancies (NRT) received no intervention. MFPR was performed at 12-13(+6) weeks of gestation (MFPR12) in 91 RT cases, 14-15(+6) weeks in 32 cases (MFPR14), while at 16-24(+6) weeks of gestation in 29 cases (MFPR16). The procedure was performed by transabdominal ultrasoundguided intracardiac injection of 10% KCl solution. Results: Pregnancy loss rates in the RT and NRT groups were 14.5% and 6.7%, respectively. The difference between the two groups was statistically significant (X-2 = 4.857, P = 0.028). Pregnancy loss rate for the MFPR16 group (31.0%) was significantly higher than for MFPR12 (8.8%, P = 0.007) and NRT group (6.7%, P = 0.000). The differences between pregnancy loss rates of the MFPR12 and MFPR 14 groups and the rate of NRT group were not statistically significant (P > 0.05). Conclusion: There was an increased risk of pregnancy loss in the RT pregnancy group in comparison with NRT group. However, performing MFPR before gestational age of 16 weeks could reduce the risk of pregnancy loss significantly.