Really?
It’s always useful to look at the actual paper before jumping to conclusions–particularly when sometimes imprecise terms such as “progestins” are used. Sometimes “progestins” refers to a patentable quasi-progesterone drugs as distinct from human progesterone. Sometimes it is used more nebulously to include human progesterone.
Standardized use of nomenclature would be welcome from the health industry, but if bioidentical progesterone is included in the study perhaps you could point out the numbers as I only did a cursory reading.

But we do get this statement:

“Combined therapy with norethisterone was associated with an increased risk of epithelial ovarian cancer (RR, 1.55; 95% CI, 1.36-1.76), which was not significantly different from the RRs associated with medroxyprogesterone, levonorgestrel, or cyproterone acetate (Table 3).”

Here “combined therapy” (the almost always necessary opposing estrogens with a progestogen) only references “progestins” in the form of patentable quasi-progesterone drugs.

Some very “umm, interesting ideas” – I should be inured to it by now but I’m not.

News item about HRT and ovarian cancer (will replace with direct link to JAMA when it comes up).

Update: Hormone Therapy and Ovarian Cancer.
Lina Steinrud Mørch, MSc; Ellen Løkkegaard, MD, PhD; Anne Helms Andreasen, MSc; Susanne Krüger-Kjær, MD, DrMSci; Øjvind Lidegaard, MD, DrMSci JAMA. 2009;302(3):298-305.

The doctors mentioned (Marian Gluck and John Moran) both show up online as having, umm, interesting ideas about treating menopausal symptoms and similar using nutritional supplements and offering a range of blood tests, details not given on the web site I saw.

That is not “evidence-based” science.
To reach a conclusion that “all hormone therapies” must be considered to have the same risk on the basis of insufficient evidence to prove otherwise is nonsense.
Simply because a hormone and hormone-like drug happen to operate on a common receptor hardly gives evidence-based justification to conclude the side effects are the same, or even similar, particularly when the metabolization and action of the metabolites are well known to be very different.
Ask yourself, for example, why MPA is not given to sustain risky pregnancies rather than real progesterone.

I wonder how much of an expectation there is that might influence the client/patient perception that any irritating symptoms can’t possibly be side-effects?

I must look out for the Reader’s Digest version as any differences might be interesting and quite an insight into the expected audiences. Was it the same author (Jerome Burne)?

As you say, commercial BIH are regulated and carry warnings; it seems absurd that competitor products are not bound by similar standards when they hope to have a pharmaceutical effect but bypass the need for regulation by representing themselves as a different industry.

To quote Chris MacDonald:

The side-effects of drugs…only become known *because* they are carefully studied and monitored. Sometimes such discoveries are made later rather than sooner — but better that it’s well-studied than not.

…Drug companies are forced, by the legal and ethical standards that government them, to design drug trials carefully to rule out the dozens of ways in which personal, first-hand observation is likely to be biased. If drug companies were allowed to market a drug based solely on mere anecdotes from happy customers, can you imagine just how bad that would be?

Bertolt Brecht pithily summed up the rationale for scrutinising evidence: Life of Galileo:

The aim of science is not to open the door to infinite wisdom, but to set a limit to infinite error.

Unfortunately, there is no evidence to persuasively and conclusively demonstrate that the risks with bioidentical hormones are any less significant than with conventional hormone therapy. Consequently, an evidence-based approach is to apply the WHI risk and benefit findings to all hormone therapies.

Consumers that select pharmacy-compounded bioidentical hormones face additional risks, beyond that of the WHI – most importantly, batch-to-batch variation, and formulation differences, which means that safety and efficacy data, even from trials that have studied bioidentical hormones, cannot be considered to be applicable.

Bioidentical hormones that are commercially manufactured (yes, there are several) are subjected to evaluations of product quality, safety, efficacy, etc. All carry appropriate warnings consistent with the findings of the WHI study.