Estradiol: micrograms or milligrams

Abstract

SummaryEstrogen is used to induce puberty in peripubertal girls with hypogonadism. Although both synthetic and natural forms are available, along with different routes of administration, in the UK oral ethinyl estradiol and the low-dose oral contraceptive pill are commonly used as hormone replacement therapy for practical reasons. We present five peripubertal girls (aged 12.5–14.9 years) with hypogonadism (two with primary hypogonadism due to Turner syndrome and three with central (secondary) hypogonadism as part of multiple pituitary hormone deficiency) who for a variety of reasons have received milligram doses of estradiol (E2) in error for between 6 weeks and 6 months, instead of the expected microgram doses of ethinyl estradiol. Although there are no direct comparisons in peripubertal girls between synthetic and natural estrogens, all girls had vaginal bleeding whilst receiving the milligram doses and have ended up with reduced final heights, below the 9th centile in 1 and below the 2nd centile in 4. Whilst reduction in final height may be part of the underlying condition (especially in Turner syndrome) the two girls with height predictions performed prior to receiving the estrogen overdose have not achieved their predicted height. Estrogen is one of the few drugs which is available in both milligram and microgram formulations. Clinicians need to be alert to the possibility of patients receiving the wrong formulation and dosage in error.Learning pointsGirls with primary and secondary gonadal failure require assistance with pubertal induction.Although several different formulations and route of administration are available, for practical reasons, the majority of girls in the UK receive oral ethinyl estradiol.Estrogen preparations are available in both milligram and microgram formulations, with potential for receiving the wrong dose.Girls receiving milligram rather than microgram preparations all had vaginal bleeding and a short final height.

Use of contraceptives and risk of inflammatory bowel disease: a nested case–control study

“… 28 For those pills-containing estradiol, we treated 200 μg estradiol as bioequivalent to 1 μg ethinylestradiol. 29 , 30…”

“…28 For those pills-containing estradiol, we treated 200 µg estradiol as bioequivalent to 1 µg ethinylestradiol. 29,30 "Average months of contraceptive pill exposure per year of follow-up" was calculated and treated as both a continuous variable and separately as categorical variable in quantiles of three months per year to check for evidence of non-linearity with the development of IBD. This was done separately for COCPs and POPs.…”

Hormone supplementation for pubertal induction in girls

“…Possibly, the choice of oestrogen matters little at the start of pubertal induction where low dosage is of great importance. While there is good evidence that puberty can be induced too quickly leading to reduced final height, the question whether it can be induced too slowly cannot be answered with confidence 35. Review of the current literature suggests that for long-term hormone replacement, oral/transdermal17β-oestradiol needs to be favoured over preparations containing ethinyloestradiol, given their higher cardiovascular risk.…”

Impact of frozen thawed embryo transfer in hormone substituted cycles on thrombotic risk markers

“…The discrepancy in the number of women with affected thrombin generation could be due to the difference in chemical properties of estrogen in the two tablets with ethinyl estradiol in oral contraceptives and natural human estradiol used in AC-FET. It is well known, that ethinyl estradiol is more potent than natural human estradiol, 1 μg ethinyl estradiol is equivalent to 100-250 μg estradiol [29]. Moreover, there is a different estrogen dosage (6 mg) in AC-FET compared to the quantity (20-30 μg) used in oral contraceptives.…”