Effect of Teratozoospermia in IVF / ICSI Cycles

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Effect of teratozoospermia in IVF and ICSI cycles

Influence of sperm morphology on pregnancy outcome and offspring in in vitro fertilization and intracytoplasmic sperm injection: a matched case-control study

A retrospective, matched, case-control study was conducted to evaluate the impact of teratozoospermia in ART (assisted reproductive technology), specifically IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection).

An initial 10,273 IVF/ICSI cycles carried out, at the Reproductive and Genetic Hospital of CITIC-Xiangya, in Changsha, China between June 2013 and June 2018, was assessed against a strict exclusion / inclusion criteria.

Following propensity score matching, a total of 2202 IVF cycles (734 teratozoospermia, 1468 normal) and 2574 ICSI ( 1287 teratozoospermia, 1287 normal) was identified. Teratozoospermia was defined as < 4% of sperm with normal morphology, according to WHO guidelines, with semen samples collected 3 to 5 days after sexual abstinence.

Semen preparation for IVF cycles used the swim-up or discontinuous gradient method followed by co-incubation of at least 1 × 105 motile sperm with the partners oocytes. For ICSI manipulation, sperm was prewashed and incubated for at least 1 hour before any motile sperm was selected and then injected according to standard protocols.

Embryos were then checked for fertilization 16 to 18 hours after insemination or microinjection, followed by morphological assessment on day 3 and transfer of high quality embryos. The rate of fertilization, cleavage, optimal embryos and implantation rate was all recorded, followed by clinical pregnancy rates, live births, complications, defects and disease in the infants, up to the age of one.

Baseline characteristics of the two IVF only groups (teratozoospermia, normal) was comparable although the use of frozen semen was significantly higher in the teratozoospermia group. Nevertheless prewashed semen volume and total motile sperm count was not significantly different between the 2 groups.

Surprisingly fertilization rate among the teratozoospermia group was only slightly decreased (77.33% vs 77.84%) while optimal embryo rate showed a statistically significant decrease (57.86% vs 59.98%). Interestingly pregnancy rates (53.95% vs 55.79%) and abnormal pregnancy’s was only slightly different. Similarly pregnancy complications was also slightly elevated in the teratozoospermia group, however the rate of gestational hypertension was significantly higher (4.04% vs 1.95%). Further statistical analysis of IVF outcomes, dividing the neonates according to singleton, twin and triplet births, showed a potential risk of lower mean birth weight among teratozoospermia only triplets, with all other neonate outcomes being comparable.

In the ICSI only groups (teratozoospermia, normal), baseline characteristics was also comparable although the use of frozen semen was significantly higher in the teratozoospermia group and overall worse quality (volume and concentration).

Similar to the IVF group results, fertilization rate was slightly decreased (84.47% vs 85.54%) among the teratozoospermia group, however this did not affect the rate of optimal embryo’s (60.72% vs 59.93%) unlike the IVF only group. Pregnancy rate trended higher in the teratozoospermia group (54.70% vs 50.89%) although all other outcomes, including abnormal pregnancy’s and complications remained comparable between the groups. Additional analysis of the ICSI groups dividing the neonates according to singleton, twin and triplet births also found no difference; in the number of gestation weeks, infant birth weight, premature birth rate and rate of birth defects.

Overall the results showed that although teratozoospermia may impair embryo development, in IVF cycles, no further effect was seen in all other parameters, suggesting teratozoospermia has no real predictive value in pregnancy outcomes following IVF / ICSI cycles.


In this study comparing teratozoospermia diagnosed males to males with normal semen, as per WHO guidelines, teratozoospermia did not show any significant effect on fertilization or pregnancy rates, in both IVF (77.3% vs 77.8% or 54.0% vs 55.8%) and ICSI cycles (84.5% vs 85.5% or 54.7% vs 50.9%).


  1. Retrospective study
  2. Different types of sperm defect not recorded or analysed

Similar studies

Berger D S, et al. (2011). Severe teratozoospermia and its influence on pronuclear morphology, embryonic cleavage and compaction. https://doi.org/10.1186/1477-7827-9-37

French D B, et al. (2010). Does severe teratozoospermia affect blastocyst formation, live birth rate, and other clinical outcome parameters in ICSI cycles. https://doi.org/10.1016/j.fertnstert.2008.10.051

Dubey A, et al. (2008). The influence of sperm morphology on preimplantation genetic diagnosis cycles outcome. https://doi.org/10.1016/j.fertnstert.2007.06.052

Keegan B R, et al. (2007). Isolated teratozoospermia does not affect in vitro fertilization outcome and is not an indication for intracytoplasmic sperm injection. https://doi.org/10.1016/j.fertnstert.2007.01.057

McKenzie L J, et al. (2004). Pregnancy outcome of in vitro fertilization/intracytoplasmic sperm injection with profound teratospermia. https://doi.org/10.1016/j.fertnstert.2004.03.054

Terriou P, et al. (1997). Teratozoospermia influences fertilization rate in vitro but not embryo quality. https://doi.org/10.1093/humrep/12.5.1069


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