Conventional IVF Yields Better Clinical Pregnancy Rates than ICSI in Older Patients with Unexplained Infertility

Introduction

ICSI was initially developed to treat male infertility in IVF programs. However, based on the remarkable success, and despite the added cost, uncertain efficacy, and potential risks of ICSI, its use has been extended to non male-factor infertility patients, such as couples with unexplained infertility.

Aim

To investigate whether insemination by ICSI or conventional IVF yields better clinical outcomes in couples with unexplained infertility, including implantation, pregnancy and live birth rates.

Materials and methods

A longitudinal prospective cohort study consisted of 435 infertile couples referred to ART in Hadassah Mount Scopus - Hebrew University Medical Center due to unexplained infertility, from 2008 till-2014. Oocytes harvested from a single patient after an ART cycle were randomly divided for ICSI or conventional IVF insemination. Embryos were transferred according to standard criteria. From this cohort we identified patients whose all transferred embryos were the product of only one insemination technique (n=343). Patient and cycle characteristics as well as rates of fertilization, cleaving and good- quality embryos, chemical pregnancy, implantation, clinical pregnancy, abortion and live birth were recorded.

Results

Our data show comparable fertilization rates (0.61 vs. 0.58, p=0.138), cleavage rates (0.56 vs. 0.53, p= 0.093), and good quality embryos rates (0.42 vs. 0.39, p=0.066) between ICSI and conventional IVF even when controlled for patientsage or source of sperm. As expected, comparing only the selected mature oocytes actually allocated for ICSI showed superiority over conventional IVF on the same outcome measures. There was no difference in clinical pregnancy rates (0.35 vs. 0.4, p=0.365), miscarriage rates (0.08 vs 0,07, p=0.648 ) and live birth rates (0.26 vs. 0.32, p=0.225 ) between ICSI and IVF, respectively. Conventional IVF was found to yield higher clinical pregnancy rates in women above the age of forty (0.16 vs. 0.39, p=0.04) and when frozen thawed donor sperm was used (0.23 vs 0.44, p=0.049). However, the percentage of patients diagnosed with total fertilization failure was significantly lower with ICSI (16% vs. 2%, p<0.001).

Conclusions

In young unexplained infertility patients, conventional IVF and ICSI yield similar pregnancy and live birth rates. Patients over 40 years may benefit from conventional IVF, which yielded better clinical pregnancy rates. However, the use of ICSI reduced the incidence of total fertilization failure in unexplained infertility patients.