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Chapter: Medicine Study Notes : Reproductive and Obstetrics

Contraception - Gynaecology

Ideal contraceptive is 100% effective, only desirable side-effects, readily reversible, and able to be used un-supervised



·        Ideal contraceptive is 100% effective, only desirable side-effects, readily reversible, and able to be used un-supervised

·        Reference: OHCS + numerous pamphlets

·        For a younger person wanting to start on the pill:

o   Discuss the possibility of coercive sex, especially if under 15

o   Discuss the emotional and physical consequences of sex

o   Ask about prior contraceptive use 

o   Ask whether they want to become pregnant – establish a context for motherhood in terms of the next 5 years and their life goals 

o   Find out their thoughts about birth control (many myths: birth defects, ¯ fertility)

o   Inform about all methods

·        Risk assessment questions:

o   Current sexual history

o   Past problems with weight gain

o   Acne

o   Headaches/migraines

o   Dysmenorrhoea/irregular menses

o   Nausea/abdominal pain

o   Diabetes

o   Smoking

o   Personal or family history of DVT

o   Hypertension or IHD


Natural Family Planning


·        No intercourse from 6 days before to 2 days after ovulation – free and no drugs

·        Monitor fertility by:

o   Checking cervical mucus – clear and stretchy when fertile

o   Temperature ­ 0.3 C after ovulation (affected by fevers, drugs, drink)

·        Success if regular cycles, dedication and self-control

·        Peak effectiveness is 2% - usually 10 - 20 % (pregnancies per woman years)


Barrier Methods


·        Low health risk, need high motivation, some STD protection

·        Condoms, Caps +/- spermicide, female condom (Femidom)

·        Don‟t use oil-based lubricant or anti-thrush cream with condom

·        Spermicide gives extra protection




·        Eg Novagard

·        Very effective (failure rate 1-2 per 1000 woman years)

·        Inhibit implantation and may impair sperm migration

·        Need replacing every 3 – 5 years

·        Best in older, parous women in stable relationships

·        Contraindications: Pregnancy, high risk for STD, undiagnosed vaginal bleeding, very heavy periods

·        Complications:

o  Can be expelled from a nulliparous or distorted (eg fibroids) uterus

o  Ectopic pregnancy more likely (1 in 2000)

o  Associated with PID following insertion or STD 

·        If she becomes pregnant then must take the IUCD out (little risk of inducing miscarriage). If it‟s left in then ­risk of chorioamnioitis, miscarriage or pre-term labour 

·        Mirena – carries levonorgestrel (a progesterone) ® ¯risk of implantation and lighter periods (Good for menorrhagia). Lasts 3 years. 20% experience reversible amenorrhoea. Expensive. Can use with oestrogen only HRT (no ­risk of endometrial hyperplasia) and avoid progesterone side effects


Combined Oral Contraceptive


·        Initial exam should include:

o  Weight

o  Blood pressure

o  Cervical screen if appropriate

·        = Oestrogen (usually ethinylestradiol) + progestogen:

o  Oestrogens: 

§  Ethinylestradiol (most common), mestranol (which is converted to estradiol. 50 mg mestranol = 35 mg estradiol) 

§  High dose = 50 mg estradiol. Low dose is <= 30 mg oestrogen. Adverse effects are dose related Þ give lowest dose that gives good cycle control. 

o  Progestins: 

§  Estranes: norethindrone, ethynosiol acetate, norethindrone acetate (latter two converted to the former) 

§  Gonanes: norgestimate, levonorgestrel, desogestrel (gonanes have a longer half-life)

·        About 4 * physiological dose of oestrogen 

·        Triphasic pill: mimic‟s body‟s fluctuation in oestrogen but ® ­break through bleeding

·        Action: G type mucus + ¯GnRH (® no ­FSH or LH surge).  „Puts the ovary to sleep‟

·        Take for 3 weeks, then pill free for a week ® withdrawal bleed 

·        Benefits of CoC: 99% effective, reversible, lighter periods, ¯PMS, ¯ovarian and endometrial carcinoma (but slightly ­risk of breast cancer), ¯endometriosis 

·        Problems: compliance

·        Contraindications:

o  > 35 and smoker (death 8 times more common in smokers – but still as safe as childbirth) 

o  Any disorder predisposing to venous or arterial problems, eg ­ lipids, APC resistance

o  Many cardiovascular problems (except mild hypertension)

o  Liver disease 

o  Migraine with aura or for > 72 hours (status migrainosus) or requiring ergotamine. Pill ® 4 times risk of ischaemic stroke. Contra-indicated in any woman with migraine if > 1 other risk factor for stroke (lipids, BP, diabetes, etc) 

o  Pregnancy

o  Undiagnosed uterine bleeding

o  Gross obesity or immobility (stop before major surgery)

·        Special precautions: Family history of DVT, ­BP or breast cancer; epilepsy, diabetes, illnesses causing diarrhoea (eg Crohn‟s)


·        Side-effects: (usually worse when starting the pill), intra-menstrual bleeding, breast tenderness, nausea,


§  or ¯ weight, mood changes, headaches

·        Risks:


o   MI.  Risk ­ sharply over 40 – 1:2500 for non-smokers, 1:500 for smokers. 

o   Older progesterones: breakthrough bleeding, acne, headache, ­weight ® lead to search for new progesterones (ie 3rd generation progesterones like gestodene eg in Mercilon, etc)

o   Nausea: due to oestrogen.  Take with meal or with a snack at bedtime 

o   ­Blood pressure (rare – but monitor 6 monthly)

o   DVT Risk (Source: Medsafe flier)


·        35/100,000 on the pill per year develop a clot, one dies Þ two deaths per year in NZ

·        Risk increases 3-4 times over population risk on 2nd generation, 6 – 8 times on 3rd generation. Increased risk of Diane 35 and Estelle 35 of 4 times over 2nd generation. 

·        No ­risk with PoP


·        Drugs interfering with the pill: liver enzyme inducers (eg anticonvulsants, rifampicin). Consider higher dose pill 

·        Monitoring: 6 monthly-BP check. Check weight and breasts etc if > 35.  Up to date with smears?

·        Starting the pill:


o   On day 1 of cycle, or day of TOP, 3 weeks post-partum or 2 weeks after mobilisation after major surgery. Contraceptive cover immediate


o   Breakthrough bleeding is very common – especially in the first 3 months. Can add 20 mg estradiol every 24 hours, 12 hours after the usual pill, for one week.


·         Missed pill: 12 hours late OK, after that the seven day rule (also if diarrhoea) – take 7 active pills before unprotected sex (eg if pill free days coming then skip them and go straight onto the next pack)

·        Stopping:

o   66% menstruate within 6 weeks, 98% by 6 months


o   At menopause: Stop at 50 with > 1 years amenorrhoea. CoC masks menopause, so stop at 50 and use non-hormonal method. Little evidence that it‟s not safe to continue to menopause


Progesterone Only Pill (PoP)


·        = Mini-pill 

·        ® Cervical mucus hostile to sperm (G Type mucus) + prevent ovulation in some + ¯tubal motility. 

·        Effectively a barrier method. Woman may still ovulate. Small risk of follicular cyst (one that doesn‟t pop) ® pain with full bladder or rectum 

·        Worst side effect: erratic bleeding. Some women have amenorrhoea. Less risk of weight gain, acne, depression, breast tenderness, headache 

·        Less effective than CoC (0.3 – 4% failure) – age and compliance dependent 

·        OK where CoC contra-indicated and in breast-feeding mums (full breast feeding alone is protective for 3 months). For post-partum contraception see Six Week Check

·        Contraindications: History of ectopic pregnancy, breast cancer, liver disease or enzyme inducing drugs

·        Must be taken same time each day (+/- 3 hours).

·        Starting on the PoP: Alternative precautions for 7 days

·        If pill missed then at risk for 2 days.  Safe again after 2 days of restarting the pill

·        Depot progestogen:


o   Safe, simple and effective (failure rate 0.4 – 1.2 %). Suppress ovulation, G type mucus, ¯ motility and implantation


o   Eg Depot-provera – deep IM 12 weekly, given during first 5 days of cycle, 5 days post partum if bottle feeding, 6 weeks if breast feeding.


o   Contraindications: pregnancy, abnormal undiagnosed vaginal bleeding, acute liver/cardiac disease


o   Advantages: no oestrogen, ¯PMS, secret, no compliance problems, good with GI disease, Ok with breast feeding, etc… Particularly good around major surgery, epileptics, after vasectomy and bowel disease


o   Problems: irregular bleeding – usually become amenorrhoea, also weight gain and acne. May also ­depression and ¯libedo. Median delays of 10 months return to ovulation on stopping (fat soluble ® very slow metabolism)




·        Reversal is only 50% successful Þ see it as irreversible

·        Tubal ligation has 1% failure (1:200) – 10 times worse than vasectomy and same as IUCDs 

·        Vasectomy – easier than tubal ligation, but takes up to 3 months before stored sperm used up. Need to be tested and have 2 sperm-free ejaculates. Has been discussion of ­risk of prostate cancer – best evidence says no association.


Emergency Contraception


·        Ask why: unprotected intercourse, condom broke, etc.  If no condom, then check why.  If indicated:

·        „Are you worried about infection?‟ and „Was it OK with you that it all happened the way it did‟

·        [checking for non-consensual intercourse]

·        Ask:

o  How long ago was sex?

o  LMP 

o  Regular partner (® ¯risk of STD)

o  Medications

o  Previously had an ECP – any side effects.  Sometimes nausea +/- vomiting with Progesterone only

o   ECP 

o  Other conditions. Old Oestrogen + Progesterone ECPs required history of DVT and focal migraine 

·        If sex < 72 hours ago prescribe:

o  Nordiol 2+2/Antinaus 5mg (12 hours apart, few side effects) or

o  2/Microval 25+25 (can have while breast feeding, may reduce breast milk for ~ 1 week)

·        Discuss:

o  How to take it

o  Pregnancy test in three weeks

o  Ongoing contraception, other advice 

·        Emergency IUCD: inserted within 120 hours of unprotected intercourse. Screen for STDs. Prophylactic cover if suspected


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