Add-ons in the laboratory: hopeful, but not always helpful.

All the steps in an in vitro fertilization cycle are important but none more so than those that occur in the laboratory. To improve the chance of success, adjuncts, commonly referred to as 'add-ons', are offered. Yet as with other new interventions, add-ons in the laboratory require justification by well-designed studies prior to being offered as routine practice. Add-ons aim to improve the chance of a take-home baby, but, their safety and efficacy is less than clear. In addition, the financial burden from the use of add-ons is often borne by the couple. This review of the most commonly used laboratory add-ons did not find any high-quality evidence to support their use in routine practice.