Assisted reproductive technology and risk of adverse obstetric outcomes in dichorionic twin pregnancies A systematic review and meta analysis

This study aims at examining whether dichorionic twin pregnancies resulting from assisted reproductive technology have a higher risk of adverse obstetric outcomes compared with those conceived naturally by conducting a systematic review and meta-analysis.

Jiabi B. Qin, M.D., Ph.D., Hua Wang, M.D., Xiaoqi Sheng, M.D., Qiong Xie, M.D., Shiyou Gao, M.D.

Volume 105, Issue 5, Pages 1180-1192


To examine whether dichorionic twin pregnancies after assisted reproductive technology (ART) were at higher risk of adverse obstetric outcomes compared with those conceived naturally.


University-affiliated teaching hospital.

Dichorionic twin pregnancies conceived with ART and naturally.

Studies comparing obstetric outcomes in dichorionic twin pregnancies conceived by ART and naturally were identified by searching PubMed, Google Scholar, Cochrane Libraries, and Chinese databases through July 2015 with no restrictions. Either a fixed-effects or a random-effects model was used to calculate the overall combined risk estimates. Subgroup analysis was performed to explore potential heterogeneity moderators.

Main Outcome Measure(s):
Maternal complications and adverse pregnancy outcomes.

Fifteen cohort studies involving 6,420 dichorionic twins after ART and 13,650 dichorionic twins conceived naturally were included. Most of maternal complications were similar in both groups, but placenta previa (relative risk [RR] = 2.99, 95% confidence interval [CI] 1.51–5.92; I2 = 0) was significantly more common in the ART group. For neonatal outcomes, the ART group experienced higher risk of preterm birth (RR = 1.13, 95% CI 1.00–1.29; I2 = 75%), very preterm birth (RR = 1.39, 95% CI 1.07–1.82; I2 = 71%), low birth weight (RR = 1.11, 95% CI 1.00–1.23; I2 = 61%), and congenital malformations (RR = 1.26, 95% CI 1.09–1.46; I2 = 26%). In addition, the ART group had a higher proportion of elective cesarean sections (RR = 1.79, 95% CI 1.49–2.16; I2 = 60%), but had a similar proportion for emergency cesarean sections. Relevant heterogeneity moderators have been identified by subgroup analysis. No evidence of publication bias was observed.

The rates of placenta previa, elective cesarean section, preterm birth, very preterm birth, low birth weight, and congenital malformations were significantly higher in dichorionic twin pregnancies after ART.

  • mariovegamd

    Very interesting article that argues against the common idea that IVF twins do better than naturally conceived twins. The main thought behind it is that IVF twins were more closely monitored therefor will fare better. Sometimes, over monitoring is not better, and this could explain the elevated cesarean section rate. Many of the outcomes assessed, such as preterm birth and elevated risk of preeclampsia have been associated to elevated E2 levels at the time of fresh embryo transfer. It would be helpful to perform a sub-analysis of the different types of embryo transfer when compared to natural conceptions. Did the authors look at this?


    • Jiabi Qin

      Thank you for your attention. I admit this is a very interesting question. It would be helpful if a sub-analysis of the different types of embryo transfer was performed when compared with spontaneous conceptions. However, it is difficult, presently, to conduct this work because of limited information in the included studies.

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