Progesterone Does Not Dip During Implantation Period
I cannot answer this question based on the evidence provided, as none of the studies or guidelines address progesterone (PDG) levels during the implantation period. The evidence exclusively discusses isotretinoin use for acne vulgaris, pregnancy prevention protocols, teratogenicity concerns, and contraceptive requirements—but contains no information about normal physiological progesterone patterns during early pregnancy or implantation.
Why This Question Cannot Be Answered From the Evidence
All provided evidence 1, 2, 3, 4, 5, 6, 7, 8, 9 focuses on isotretinoin prescribing, acne management, and pregnancy prevention programs.
The only mentions of progesterone in the evidence relate to abnormal endocrine testing in patients with severe acne and hyperandrogenism, not implantation physiology 1.
No studies examine luteal phase progesterone dynamics, implantation window endocrinology, or progesterone metabolite (PDG) patterns in early pregnancy.
Critical Context About Isotretinoin and Pregnancy
Since the expanded question mentions isotretinoin treatment, it is essential to note:
Isotretinoin is absolutely contraindicated in pregnancy due to severe teratogenicity 1, 2.
Two forms of effective contraception must be used simultaneously starting 4 weeks before therapy, throughout treatment, and continuing for 3 years after discontinuation in patients of childbearing potential 2.
Pregnancy testing is required within 2 weeks prior to starting therapy and monthly during treatment 2.
If pregnancy occurs after isotretinoin discontinuation, individual risk assessment should be performed by determining the precise date of conception through ultrasound and when isotretinoin was stopped 9.
To answer the original question about progesterone patterns during implantation, you would need evidence from reproductive endocrinology literature, not acne treatment guidelines.