P–405 The diagnosis and management of heterotopic intramural pregnancy after in vitro fertilization-embryo transfer: six-case series
Authors: Cai P , Li X , Ouyang Y , Gong F 
Published: August 2021

Study question

What are the ultrasonic characteristics of heterotopic intramural pregnancy (HIMP)? How to manage and what about the clinical outcomes of HIMP?

Summary answer

Expectant management may be a considerable choice for an non-viable intramural pregnancy (IMP). Most intrauteine pregnancies (IUPs) of HIMPs seems to have good outcomes.

What is known already

Heterotopic pregnancy (HP) post in vitro fertilization is very rare in infertility women, with a prevalence of 0.04%. HIMP is one of the rarest types of HP, where one gestational sac (GS) is embedded within the endometrial cavity and the other one GS is implanted in the myometriun. HIMP was firstly and only described by Jiangtao Lyu et al. in 2018. So far, little is known about its natural history and ultrasonic imaging characteristics. And there is no consensus regarding the ultrasound diagnosis and clinical management for HIMP due to few evidence-based medicine records.

Study design, size, duration

A retrospective observational study was conducted of 6 infertile women who obtained a HIMP through in vitro fertilization-embryo transfer (IVF-ET) between January 2009 and December 2019 at our reproductive centre.

Participants/materials, setting, methods

Six infertile women conceived a HIMP via IVF-ET were retrospectively retrieved between January 2009 and December 2019 at the Reproductive and Genetic Hospital of CITIC-Xiangya (Changsha City, China). The ultrasound diagnosis, clinical management and pregnancy outcome of these cases were analysed. The ultrasound findings, therapeutic methods and clinical outcomes were obtained from the hospital’s electronic medical records. This study was approved by the local ethics committee. Main results and the role of chance: Six women with HIMPs were retrospectively analysed. Among them, 5 cases were revealed by ultrasound scans; however, one case was misdiagnosed. The diagnostic accuracy was 83.3%.

Five cases of HIMP were diagnosed at initial scan. The diagnostic time ranged from 22 to 38 days after ET (5 + 6 - 7 + 6 weeks). Among them, an intramural GS was observed in all 5 cases; embryonic cardiac activity (ECA) was detected in one case by the followed-up scans; there was a yolk sac only in one case; an empty GS was noted in 3 cases. An IUP was revealed in all 6 cases, and ECA was observed in 5 cases at the initial diagnosis or later. A GS with a yolk sac only was showed in one case.

Among the 5 diagnostic women, one case with a live IMP was treated with laparoscopy at 8 + 1 weeks, 4 cases were managed expectantly. Of them, the IUPs of 4 cases delivered live infants and one case managed expectantly experienced miscarriage. In one case, IMP was misdiagnosed as interstitial pregnancy at day–28 scan. Exploratory laparoscopy and foetal reduction were performed at 8 + 2 weeks. Laparoscopy confirmed an IMP and the retained IUP delivered a live infant.

Limitations, reasons for caution

The case numbers are too few to draw any objective conclusions, because of the extreme rarity of HIMP. Thus, a further multi-centre larger prospective study will help to confidently illustrate the clinical significance, and effective and appropriate management method for women with a HIMP.

Wider implications of the findings: Our study showed that HIMP may not be as rare as previously reported. Increased awareness of this condition, better comprehension of the diagnostic criteria and improved resolution of ultrasound equipment may result in more frequent and accurate detection of HIMP, which will be helpful for early management to preserve IUP.

Trial registration number

Not applicable.