Since the inception of in vitro fertilization (IVF), monitoring of controlled ovarian stimulation (COS) has traditionally involved numerous appointments for ultrasound and laboratory testing to guide medication use and dosing, determine trigger timing, and allow for measures to reduce the risk of ovarian hyperstimulation syndrome (OHSS). Recent advances in the field of assisted reproductive technology (ART) have called into question the timing and frequency of COS monitoring appointments, as discussed in this commentary.

Alternative ovarian stimulation protocols for in vitro fertilisation (IVF) have grown in popularity. Yet, patient populations best suited for these protocols have not been defined. Our objective was, therefore, to determine national IVF utilisation patterns and live birth rates of various ovarian stimulation protocols.
Retrospective cohort study.
Academic-affiliated private fertility centre.
Aggregate data published by Society for Assisted Reproductive Technology for autologous IVF cycles performed in the USA during 2014 and 2015 were analysed. IVF cycles were stratified based on ovarian stimulation protocol: 205 705 conventional stimulations, 4397 minimal stimulations, 2785 natural cycles and 514 in vitro maturation (IVM) cycles. Repeat cycles could not be determined in this analysis.
Utilisation patterns and age-specific live birth rates for various ovarian stimulation protocols.
With advancing female age, utilisation of conventional stimulation protocols decreased, while minimal stimulation and natural cycle IVF increased. Diminished ovarian reserve diagnoses were in all age groups less prevalent in patients undergoing conventional stimulation than with all other protocols. Live birth rates were highest with conventional stimulation at 42.4%, 33.1%, 22.1%, 11.7% and 3.9% for <35, 35-37, 38-40, 41-42 and >42 female age groups, respectively. The difference in live birth rates between conventional stimulation and other protocols widened with advancing age from 1.6-fold to 3.9-fold among women <35 years of age, reaching 4.4-fold to 6.6-fold among women >42 years of age.
In comparison to conventional stimulation IVF-minimal stimulation, natural cycle IVF and IVM protocols offer lower but still acceptable live birth rates among young women. These alternative protocols are frequently used in older women and those with diminished ovarian reserve, despite their lower live birth rates. The reasons for this apparent incongruity warrant further careful exploration.