Oestrogen (Hormone Replacement Therapy) Pregnancy: CONTRAINDICATED — not for use in pregnancy; oestrogen is associated with fetal harm at pharmacological doses

Estradiol (HRT)

Brand names: Estradot (patch), Oestrogel (gel), Elleste Solo (tablet), Evorel (patch)

Adult dose

Dose: Patch: 25-100 mcg/24h (changed twice weekly or weekly depending on brand); Gel: 0.5-1.5 mg/day (1-3 pumps); Tablet: 1-2 mg once daily

Route: Transdermal patch / transdermal gel / oral tablet

Frequency: Twice weekly (patch) / daily (gel, tablet)

Max: 100 mcg/24h patch; 1.5 mg/day gel; 2 mg/day tablet

Menopausal symptoms; add progestogen (norethisterone, dydrogesterone, micronised progesterone) for women with intact uterus to prevent endometrial hyperplasia; transdermal route preferred — avoids hepatic first-pass, lower VTE risk

Paediatric dose

Dose: Not applicable for HRT N/A/kg

Route: N/A

Frequency: N/A

Max: N/A

Paediatric use: delayed puberty (specialist endocrinology)

Dose adjustments

Renal

No dose adjustment required

Hepatic

Oral oestrogens contraindicated in severe liver disease; transdermal preferred if mild-moderate impairment

Paediatric weight-based calculator

Patient weight (kg)

Paediatric use: delayed puberty (specialist endocrinology)

Clinical pearls

MHRA 2023 updated HRT guidance: transdermal oestrogen does not increase VTE risk significantly (unlike oral oestrogens); preferred in women with elevated VTE risk, obesity, or migraine with aura — this distinction is critical in clinical prescribing
WHI trial (JAMA 2002): raised concern about breast cancer and CVD risk with oral conjugated equine oestrogen — subsequent analysis showed window of opportunity: HRT started within 10 years of menopause or before age 60 has net cardiovascular benefit; started >10 years post-menopause or >60 may carry CVD risk
Million Women Study (Lancet 2003): combined oestrogen-progestogen HRT increases breast cancer risk; oestrogen-only HRT carries lower breast cancer risk — synthetic progestogens (norethisterone) carry higher risk than micronised progesterone (Prometrium/Utrogestan); this informs modern progestogen choice
Micronised progesterone vs norethisterone: increasing evidence that micronised progesterone (Utrogestan) has lower breast cancer risk than synthetic progestogens; NICE NG23 now includes this distinction and recommends micronised progesterone as the preferred progestogen in HRT
Topical vaginal oestrogen is separate from systemic HRT: low-dose vaginal oestradiol (Vagifem, Ovestin) for genitourinary syndrome of menopause (GSM) carries negligible systemic absorption and breast cancer risk — can be used alongside or instead of systemic HRT and in breast cancer survivors with caution

Contraindications

Active VTE
Active or recent arterial thromboembolic disease
Breast cancer (active or recent)
Oestrogen-sensitive malignancies
Undiagnosed vaginal bleeding
Porphyria

Side effects

Breast tenderness
Nausea (mainly oral)
Fluid retention
Headache
Irregular bleeding (sequential regimens)
Skin reactions (transdermal patches)
VTE (lower with transdermal)
Breast cancer risk (duration-dependent)

Interactions

CYP3A4 inducers (carbamazepine, rifampicin, St John's Wort) — reduce oestrogen levels; HRT efficacy reduced
Thyroid hormone — oral oestrogens increase TBG; may require increased levothyroxine dose
Anticoagulants — monitor; oestrogens have prothrombotic effect on oral route

Monitoring

Annual symptom review
Blood pressure
BMI
Mammogram (per NHS screening schedule)
Endometrial assessment if unexpected bleeding
Bone density (if osteoporosis indication)

Reference: BNFc; BNF 90; WHI trial (Rossouw et al. JAMA 2002); Million Women Study (Lancet 2003); MHRA HRT Update 2023; NICE NG23 (Menopause 2015, updated 2024); SPC Estradot; Collaborative MNSG Lancet 2019. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators