Hypertensive disorders of pregnancy after multifetal pregnancy reduction: a systematic review and meta-analysis

Objective To systematically review the literature on hypertensive disorders of pregnancy (HDP) after multifetal pregnancy reduction (MFPR). Methods A comprehensive search in PubMed, Embase, Web of Science, and Scopus was performed. Prospective or retrospective studies reporting on MFPR from triplet or higher-order to twin compared to ongoing (i.e., non-reduced) triplets and/or twins were included. A meta-analysis of the primary outcome HDP was carried out using a random-effects model. Subgroup analyses of gestational hypertension (GH) and preeclampsia (PE) were performed. Risk of bias was assessed using the Newcastle-Ottawa Quality Assessment Scale. Results Thirty studies with a total of 9,811 women were included. MFPR from triplet to twin was associated with a lower risk for HDP compared to ongoing triplets (OR 0.55, 95% CI, 0.37-0.83; p = 0.004). In a subgroup analysis, the decreased risk of HDP was driven by GH, and PE was no longer significant (OR 0.34, 95% CI, 0.17-0.70; p = 0.004 and OR 0.64, 95% CI, 0.38-1.09; p = 0.10, respectively). HDP was also significantly lower after MFPR from all higher-order (including triplets) to twin compared to ongoing triplets (OR 0.55, 95% CI, 0.38-0.79; p = 0.001). In a subgroup analysis, the decreased risk of HDP was driven by PE, and GH was no longer significant (OR 0.55, 95% CI 0.32-0.92; p = 0.02 and OR 0.55, 95% CI 0.28-1.06; p = 0.08, respectively). No significant differences in HDP were found in MFPR from triplet or higher-order to twin versus ongoing twins. Conclusions MFPR in women with triplet and higher-order multifetal pregnancies decreases the risk of HDP. Twelve women should undergo MFPR to prevent one event of HDP. These data can be used in the decision-making process of MFPR, in which the individual risk factors of HDP can be taken into account.

Automated summary

This systematic review found that multifetal pregnancy reduction (MFPR) from triplet to twin is associated with a lower risk of hypertensive disorders of pregnancy (HDP) compared to ongoing triplets. The risk of HDP is also decreased after MFPR from higher-order to twin pregnancies. These findings can inform the decision-making process of MFPR by considering individual risk factors of HDP.