→ triggers ovulation.
Rising oestradiol (from dominant follicle) leads to LH surge
Temperature before ovulation
Slight drop in basal body temp just before ovulation.
Secondary amenorrhoea: The
cessation of menstruation in a woman with previous menses for:
≥3 months (previously regular cycles)
≥6 months if history of oligomenorrhoea
Causes of Primary Amenorrhoea
With normal secondary sexual characteristics:
Constitutional delay (family history)
Endocrine: Thyroid dysfunction, hyperprolactinaemia, Cushing’s
Androgen insensitivity syndrome
Causes of Secondary Amenorrhoea
With hyperandrogenism:
PCOS
Cushing’s syndrome
Causes of Primary Amenorrhoea
With absent secondary sexual characteristics:
Gonadal failure (Hypergonadotropic hypogonadism) ⭐Hypothalamic causes (Hypogonadotropic hypogonadism)Pituitary causesConstitutional delay of pubertyEnzyme defects / steroid synthesis defects
Primary amenorrhoea: No menstruation by:
15 years with secondary sexual characteristics
13 years if no secondary sexual characteristics
Pelvic USS pcos
> 12 follicles or >10cm³ ovarian volume suggests PCOS
FSH/LH
FSH/LH – elevated in ovarian failure - Turner’s syndrome
FSH/LH – high in premature ovarian insufficiency, low in hypothalamic causes
Associated Conditions turners
Hypothyroidism common - affects 1/3rd patients (Hashimoto’s)
Coarctation of the aorta, VSD
Horseshoe kidney
Infertility
Management turners
Growth hormone, oestrogen replacement
Raised LH:FSH ratio
Pcos
Rotterdam Criteria (2 of 3)
Oligo/amenorrhoea
Hyperandrogenism (clinical or biochemical)
Polycystic ovaries on USS
Management pcos
COCP for acne/hirsutism
Weight loss
Clomifene for fertility
Metformin may be used
Amenorrhoea + low FSH/LH + recent stress/weight loss
Hypothalamic dysfunction
Amenorrhoea + high FSH in woman <40 →
Premature ovarian failure
Primary amenorrhoea + normal breast development + absent uterus →
Androgen insensitivity syndrome
Investigations gdm
If no risk factors: OGTT at 24–28 weeks
If risk factors: OGTT at booking and 24–28 weeks
Diagnostic Criteria gdm
Fasting glucose > 5.6 mmol/L
OGTT (2hr) > 7.8 mmol/L
💡Tip: GDM = 5, 6, 7, 8
Management of GDM
If fasting BM < 7
Trial of diet and exercise for 2 weeks
If inadequate → start metformin
If inadequate on metformin → add insulin
If fasting BM > 7
(or if 6.1–6.9 + macrosomia/hydramnios)
Start insulin immediately
Management of Pre-existing Diabetes in Pregnancy
Stop all oral hypoglycaemics
Continue metformin
Start insulin
Prescribe:
Folic acid 5mg OD until 12 weeks (NTD risk)
Aspirin 75mg OD from 12 weeks (pre-eclampsia risk)
Anomaly scan at 20 weeks with 4-chamber heart view
Blood Glucose Targets in Pregnancy
Fasting: ≤ 5.3 mmol/L
1 hour post-meal: ≤ 7.8 mmol/L
2 hour post-meal: ≤ 6.4 mmol/L
Dating scan:
11–14 weeks
Anomaly scan
18–21 weeks