5.1 Types of pills

First generation oral contraceptives

• products containing 50µg or more of ethinyl estradiol (EE).

Second generation oral contraceptives

• products containing 30-35µg of EE and levonorgestrel (LNG) or norgestimate or other members of norethindrone family.

Third generation oral contraceptives

• products containing 20 or 30µg EE and desogestrel or gestodene.

Pills may also be categorized based on the amount of ethinyl estradiol :

– high dose oral contraceptives are pills containing 50µg or more of EE.

– low dose oral contraceptives include pills containing 30-50µg of EE.

– Ultra low dose oral contraceptives are pills containing less then 30µg of EE.

5.2 Mechanism of action

• inhibit ovulation by inhibiting gonadotrophin secretion via an effect on both pituitary and hypothalamic centers. The progestational agents suppress LH and estrogens suppress FSH.

• in addition, the progestational agent also makes the endometrium unsuitable for implantation and thickens cervical mucus making it impervious to sperm.

5.3 Advantages

• highly effective

• early reversibility of fertility

• does not interfere with sexual activity

• no menstrual irregularity

• can be used in nullipara

• protects against benign breast diseases, pelvic inflammatory diseases, ovarian cysts, ovarian and endometrial cancer.

• decreases menstrual blood loss and prevents iron deficiency anaemia.

• suitable for clients with history of dysmenorrhoea.

• client can discontinue use anytime on her own unlike intrauterine device and norplant which necessitate a visit to the health-care provider.

5.4 Disadvantages

• patient compliance is required.

• not suitable in lactating mothers

• no protection against sexually-transmitted diseases or AIDS

• unacceptable to some clients due to minor side-effects like nausea, vomiting, breast tenderness, headache, weight gain.

5.5 Contraindications for low dose COCs

Absolute contraindications

• breast-feeding mothers up to 6 months post-partum

• up to 3 weeks post-partum in non breast-feeding mothers

• more than 35 years of age with risk factors for cardiovascular disease e.g. hypertension, smoking, vascular disease etc.

• history of deep vein thrombosis/pulmonary embolism

• patient undergoing major surgery with prolonged immobilization

• current and past history of cardiovascular accident

• valvular heart disease with superimposed complications like pulmonary artery hypertension and atrial fibrillation.

• history of migraine with focal neurological symptoms at any age

• current or past history of breast cancer

• diabetes mellitus with complications like neuropathy and retinopathy

• current gall bladder disease or history of jaundice related with use of combined oral contraceptives

• active liver disease or cirrhosis

• benign or malignant tumors of the ovary

• patients on drugs likely to affect metabolism of the COCs e.g. Rifampicin, griseofulvin, phenytoin, barbiturates etc.

Relative contraindications

Conditions when COCs can be prescribed under supervision include :

• breast-feeding women more than 6 months post-partum.

• history of gestational diabetes, cholestasis in pregnancy or pregnancy-induced hypertension

• women under 35 years of age with risk factors for cardiovascular disease

• history of cholecystectomy

• age > 40 years

• superficial venous thrombophebitis

• uncomplicated valvular heart disease

• unexplained vaginal bleeding

• cervical intraepithelial neoplasia and cervical cancer awaiting treatment

• diabetes mellitus (well controlled) with no vascular disease

5.6 Drug interactions

Drugs which stimulate the liver’s metabolic capacity can affect efficacy of both low and high dose COCs to some extent. Patients on medications (listed below) should be counseled to choose an alternative method :

- Rifampicin

- Phenobarbitone

- Phenytoin

- Primidone

- Carbamazepine

- Ethosuximide

- Griseofulvin

- Troglitazone

It was previously thought that antibiotics which reduce the bacterial flora of the gastrointestinal tract e.g. ampicillin, tetracycline decrease the efficacy of COCs. Studies have now indicated that antibiotics can alter the excretion of contraceptive steroids but plasma levels are unchanged, and there is no evidence of ovulation^4,5.

Substantial evidence indicates that COCs potentiate the action of diazepam, chlordiazepoxide, tricyclic antidepressants and theophyline⁶. Thus, lower doses of these agents may be effective in COC users. On the other hand, COC users may require larger doses of acetaminophen and aspirin⁷.

5.6 When to start COC pills

+ COCs can be started on any day within the first five days of menstrual bleeding, preferably on the first day . It may be started between 5-14 days of menstrual cycle (if the woman has not had unprotected sex in that cycle and pregnancy is excluded) with an additional contraceptive method like condom or spermicide for the next seven days. Patient should be warned of a change in menstrual pattern.

+ three to six weeks after childbirth in non-lactating mothers. If started later than 6 weeks, pregnancy should be ruled out.

+ within first 7 days of a first or second trimester abortion.

+ immediately after stopping any other contraceptive method.

5.7 Instructions to the patient about COC pill-taking

• the client should be instructed to take one pill every day at the same time and link it with a routine daily activity to help her remember.

• if provided with 28 pill packet, she should start another packet from the very next day without any gap.

• if provided with 21 pill packet, she should wait for 7 days after finishing the pack and then start the first pill from the next packet. It should be emphasized that a gap of more than 7 days will decrease the efficacy of COCs.

5.8 Instructions to the patient in case of missed pill

• if one white pill is missed, she should take that pill as soon as she remembers and the next pill on the usual time. No additional contraceptive method is required.

• if she misses 2 pills in the first two weeks, she should take two pills on each of the next two days and an additional method is to be used for next 7 days.

• if she misses two pills in the third week, or more than 2 active pills are missed at any time, then a new packet has to be started on the same day and an additional contraceptive method to be used for 7 days .

• if she misses one brown tablet then she should throw the missed pill and take rest of the tablets as usual.

Note : Even if no pills are missed, woman should be instructed to use a back-up method for 7 days after an episode of gastroenteritis.

If unprotected sex has taken place, after missing pills emergency contraception should be prescribed.

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