[Lotus]

Hi Hannah, (good to hear from you). 

See if this sounds familiar, after initially starting progesterone therapy the benefits fade a short time later. 

This study illustrates what I was saying about inconsistency of skin application:
 
Percutaneous progesterone delivery via cream or gel application in postmenopausal women: a randomized cross-over study of progesterone levels in serum, whole blood, saliva, and capillary blood.
Randomized controlled trial
Du JY, et al. Menopause. 2013.
Show full citation
Abstract
OBJECTIVE: This study aims to investigate the distribution of progesterone in venous whole blood, venous serum, fingertip capillary blood, and saliva after its topical application in both cream and gel formulations.
METHODS: Ten postmenopausal women were randomized to receive 80 mg of progesterone cream or gel applied daily for 14 days, crossing over after a 14-day washout. On the last day of each treatment period, venous blood, fingertip capillary blood, and saliva were sampled frequently for 24 hours after the final application.
RESULTS: After progesterone cream or gel application, serum progesterone levels rose gradually, reaching a peak at 9 and 8 hours, respectively; AUC(0-24) h was significantly higher with cream (12.39 vs 8.32 ng h mL(-1), P = 0.0391). Whole venous blood levels followed a pattern similar to that of serum but were considerably lower. Saliva progesterone showed a peak at 1 and 6 hours after cream and gel application, respectively, and C(max) was comparable with cream and gel. Saliva AUC(0-24) h was substantially higher than the corresponding area under the curve for serum or whole blood but did not differ significantly by delivery method (39.02 and 58.37 ng h mL(-1), P = 0.69). In capillary blood, C(max) was reached at the same time (8 h) and was similar with both formulations; AUC(0-24) h was also similar with both formulations (1,056 ng h mL(-1) for cream and 999 ng h mL(-1) for gel) but was dramatically higher than the corresponding areas under the curve for venous serum and whole blood.
CONCLUSIONS: After application of topical progesterone, saliva and capillary blood levels are approximately 10-fold and 100-fold greater, respectively, than those seen in serum or whole blood. High capillary blood and saliva levels indicate high absorption and transport of progesterone to tissues. Reliance on serum levels of progesterone for monitoring topical dose could lead to underestimation of tissue levels and consequent overdose.
PMID 23652031 [PubMed - indexed for MEDLINE]
 
This is from dr. mercola: 
If you apply the cream to your mucous epithelial membranes that line your uterus and vagina you obtain a virtually ideal administration system. Not only is absorption through these membranes more complete than through your skin, but hormones absorbed through your vaginal membranes enter the very same pelvic plexus of veins that your ovaries normally empty into. From here the hormones are carried to your heart and lungs and distributed to your tissues just as if your ovary had actually produced them.

http://articles.mercola.com/sites/articl...tions.aspx

This news report lists a meta analysis report indicting the safety results of epithelial delivery. As always do your homework and contact your doctor for professional assessment. 

Vaginal progesterone safe and effective in preventing preterm birth
http://www.news-medical.net/news/2011121...birth.aspx