Effect of Low-dose Human Chorionic Gonadotropin on the Prevention of Ovarian Hyperstimulation Syndrome and in Vitro Fertilization Outcome

Ovarian hyperstimulation syndrome (OHSS) is a rare but most potentially life-threatening disorder in women under in vitro fertilization (IVF). This study aimed to determine the effect of low-dose human chorionic gonadotropin (hCG) on the prevention of OHSS and IVF outcome.
This single-blind non-randomized clinical trial was performed from October 2008 to November 2012 in Motahari Hospital, Urmia, Iran. Overall, 202 infertile women undergoing IVF treatment were divided into two groups based on OHSS risk factors. Then, 87 women with serum estradiol level of 5000-8000 pg/ml received 5000 units of intramuscular hCG, and 115 women with serum estradiol level of > 8000 pg/ml, who were at high risk for OHSS, received 1600 units of hCG. Data were analyzed using independent t-test and Chi-square test in SPSS, version 16.
There were no significant differences in age, infertility duration, infertility factor, quality of embryo, pregnancy rate and number of abortions and OHSS rate between the groups (P>0.05). The group that received 1600 units of hCG was in a better condition regarding the mean number of ova (11.45±5.41 versus 9.24±4.24; P=0.01), mean number of good quality ova (11.10± 5.47 versus 8.68± 4.03; P=0.001), and mean number of embryos (7.38± 4.24 versus 5.53± 2.85; P=0.001). There was no significant difference in the rate of OHSS incidence and cancellation of embryo transfer between the two groups (1600 and 5000 units).
Overall, the current study indicated that prescribing 1600 units of hCG in women who are at risk of hypersensitivity reaction may induce similar or perhaps better results regarding the quantity and quality of ova and embryos, however, OHSS risk is not completely eliminated by using a lower dose of hCG. It is therefore suggested to perform randomized clinical trials with greater sample size to verify these results.