The effect of age on the outcome of intrauterine insemination: A review


Male age, female age, succes rates, clomiphene citrate, gonadotrophins, natural cycle


Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101,
B-1090 Brussels, Belgium. Tel.: +32-2-477-66-99; fax: +32-2-477-66-49

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Aim: Postponing childbearing has led to an increasing demand for treatments due to age-related subfertility. While intra uterine insemination (IUI) is widely used for different indications, here too the age of women in need of this treatment is increasing. Success rates after IUI in relationship to age are often expressed per cycle, but for patient counselling, cumulative delivery rates are to be preferred. We reviewed the literature to assess the impact of age on IUI, and the role of ovarian hyperstimulation in improving the success rates.
Methods: A review of the literature was performed using Medline. We used the UK National Health Service levels of evidence (and grades of recommendation) to categorise all studies.
Results: Overall, controlled ovarian stimulation (COH) resulted in significantly higher live-birth rates when compared to IUI in natural cycle. Since age was not always taken into consideration in many studies, differences among them may account for inconsistent conclusions. For older women aged > 37 years, natural cycle IUI resulted in a significantly higher pregnancy rate and live birth rate than IUI with COH. In women aged 37 and younger, COH resulted in a significantly higher pregnancy rate and live-birth rate compared to natural cycle IUI (p = 0.025).
Conclusions: Above the age of 37, succes rates decline, but despite this fact, women up to 40 years, may be encouraged to continue IUI treatment, in case of donor insemination even up to 42 years of age. Overall, superovulation with IUI yields better results than unstimulated IUI, but not in women over 37 years who may rather benefit from natural cycle IUI. When the female partner is older than 35 years, a synergistic adverse effect of paternal age has been reported.