目前可以肯定，上述结论并不属实。这是因为，免疫[测定法][wiki-10]年代久远，在准确度和可靠性上存在缺陷；对于孕酮的测定，其暴露出了特异性不足的问题。其中，用于测定孕酮的[免疫蛋白][wiki-11]，会跟孕酮的代谢物——[5α-二氢孕酮][wiki-12]、别孕烷醇酮、孕烷醇酮等——产生[交叉反应][wiki-13]，最终计入到孕酮总量当中。由于口服孕酮的首过效应所产生的孕酮游离代谢物水平较高，这种交叉反应显然导致采用免疫测定法的研究项目<sup>(正如 [Simon et al., 1993][S93] 等)</sup>，明显高估了孕酮口服后产生的水平<sup>([Nahoul et al., 1993][N93]; [Nahoul & de Ziegler, 1994][NZ94])</sup>。
数十年间，有一系列关于口服孕酮引起的孕激素临床效应的发现涌现了出来，其在当时令人费解；而今有了以更精确的测定方法得到的有关口服孕酮的数据，它们变得顺理成章了。临床医学上，口服孕酮多被用于更年期妇女，保护子宫内膜免受雌激素的不受控制的刺激，从而可避免雌激素引起的子宫内膜增生——即便是在临床上的通常剂量所达到孕酮水平较低的情况下<sup>([维基百科][WIKI-CIT-2])</sup>。不过，根据一项大型观察性研究，口服孕酮并不足以抑制由雌激素促成的子宫内膜癌之风险<sup>([Davey, 2018][D18])</sup>。即便采用超高剂量，口服孕酮仍无法促成子宫内膜的完全转化（黄体期内高孕酮水平所带来的正常效应）；而经阴道给药或注射的孕酮则可有效促成转化<sup>([de Ziegler et al., 2013][Z13])</sup>。因此，和胃肠外给药不同，口服孕酮被认为不适合用于辅助生育<sup>([de Ziegler et al., 2013][Z13])</sup>。
另外，可以轻松获得的孕酮口服胶囊，在用于阴道给药时取得了成功<sup>([Miles et al., 1994][M94]; [Wang et al., 2019][W19])</sup>。孕酮口服胶囊用于直肠给药的形式显然卓有成效，也可达到远高于口服的孕酮水平，颇似直肠栓剂<sup>([Aly, 2019][AW19-RECT])</sup>。然而，这种应用形式尚未经过正式研究，而一些女性倾向跨性别者亦报告了以此法仅可获得很低的孕酮水平。
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