HMG (menotropin) dosing — clinician-directed in fertility care

Menotropins are gonadotropins purified from human urine, carrying both FSH and LH activity in one preparation. They are given by subcutaneous injection, typically daily through the stimulation phase of a cycle, and standardized by biological activity in international units rather than by mass — because the product is a mixture of glycoprotein isoforms whose potency cannot be inferred from weight.

The pharmacodynamic point that shapes dosing is that follicles respond over days, not hours. A dose given today shows up as a follicle diameter and an estradiol level several days later, which is why the label builds a waiting period into its adjustment rule rather than allowing same-day escalation.

The label also requires a specific workup before the first injection — a complete gynecologic and endocrinologic evaluation with the cause of infertility diagnosed, pregnancy excluded, the male partner's fertility status evaluated, and primary ovarian failure ruled out. That sequence is part of the dosing instruction, not a preamble to it.

Three constraints — wait five days, change by no more than one step, never exceed the ceiling — describe a controlled feedback loop, and each exists because of a specific failure mode.

• The waiting interval prevents stacking changes before the previous one has registered in follicle growth.
• The step limit prevents a large jump from converting a sluggish response into an excessive one, since the dose-response curve for ovarian recruitment is steep near the threshold.
• The daily ceiling exists because ovarian hyperstimulation syndrome sits on the same axis as therapeutic response, and it appears on the label's list of common adverse reactions rather than only in the warnings.

This is why a generic "HMG dose" is not a meaningful quantity. The number is an output of monitoring, and a person's own starting dose in a second cycle is informed by how the first one went.

Two practical points follow from IU-based potency:

• Milligram arithmetic borrowed from other peptides does not transfer. The unit is activity, not mass, and no mg-per-vial conversion carries meaning.
• The product is a powder reconstituted with a supplied diluent, so concentration depends on the diluent volume added. Where the label permits combining menotropins with a urinary FSH product in the same syringe, it specifies that only the total dose matters — which is a clean illustration that these preparations are accounted for by activity, not by volume.

Comparative data reinforce that potency and outcome are not the same thing: highly purified menotropins yielded fewer oocytes than recombinant FSH while matching it on pregnancy rates, with a less pronounced follicular response and a lower risk of ovarian overstimulation (PMID 30264288). Pushing the dose toward more follicles is not the same as pushing toward more pregnancies.

Gonadotropin dosing is titrated against measurements a person cannot take at home: serial transvaginal ultrasound follicle counts and serum estradiol. Those readings are what tell a specialist whether to hold, raise, lower, or cancel a cycle — and cancellation is itself a legitimate outcome when the response is too strong. Because OHSS can develop after the injections stop and can progress rapidly, the monitoring outlasts the dosing. That combination of a narrow ceiling, a feedback-driven adjustment rule, and a risk that persists past the last dose is why HMG dosing stays with a fertility specialist.