Recent months have seen approvals from the U.S. Food and Drug Administration for two unique combination oral contraceptives (OCs): Cyclessa(tm) (Organon Inc.) and Yasmin(r) (Berlex Laboratories).

Both of these new OCs have proved as effective as competitors in clinical trials, but each also shows significant benefit beyond the prevention of pregnancy. Cyclessa is a low-dose triphasic OC that offers improved cycle control. Yasmin, a monophasic containing a new progestin, has been shown to reduce water retention.

("Combination OCs? Triphasics? Monophasics?... translation, please")

All birth control pills contain a progestin--a synthetic form of the natural female hormone progesterone. Combination OCs also contain estrogen, and in this country, all combination OCs use the estrogen ethinyl estradiol. Today, there about 60 different OCs on the U.S. market. Three are progestin-only pills, used chiefly by women who, for one reason or another, should not be exposed to medical estrogen. The rest are combination OCs, and the meaningful differences among most of them generally center on the progestin they contain, the hormone doses they use, and the duration of the cycle.

The major trend in the development of OCs since their U.S. introduction in the early 1960s has been to find the lowest dose of hormones that will prevent pregnancy without allowing too much breakthrough bleeding or spotting--an aspect of hormonal contraception called cycle control. The estrogen dose in the first OC available in this country was a whopping 150 micrograms (mcg) and the progestin dose a hefty 9.85 milligrams (mg). Today, 40 years later, the typical combination pills use 35 mcg or less of estrogen and between 0.1 and 1.5 mg of progestin.

The principle of "lowest effective dose" has also brought about the innovation of multiphasic OCs, which vary the amount of hormones (usually the progestin) according to the week of the menstrual cycle. A typical example would be the triphasic Ortho-Novum 7/7/7, which uses 35 mcg of estrogen for all three weeks of active medication and stepped doses of the progestin norethindrone: 0.5 mg in week one, 0.75 mg in week two, and 1.0 mg in week three. Week four is an "off" week, during which the woman takes inactive placebos to maintain her daily pill-taking routine while allowing menstruation to occur.

CYCLESSA: lower estrogen, better cycle control

Cyclessa is the first triphasic OC to use an estrogen dose as low as 25 mcg; the graduated progestin (desogestrel) doses are 0.1, 0.125, and 0.15 mg in weeks 1, 2, and 3, respectively. There are four combination OCs containing just 20 mcg of estrogen, but they are monophasic, using a constant progestin dose for the three weeks of active medication. The 20 mcg estrogen dose is sufficient for contraceptive efficacy, but pills with this so-called ultra-low estrogen dose of 20 mcg are associated with more spotting and breakthrough bleeding than pills containing 30 or 35 mcg of estrogen. There are no ultra-low-dose triphasics.

U.S. clinical trial results with Cyclessa were published last year (Kaunitz. Contraception. 2000;61:295-302.). In two large studies of identical design, a total of 5,654 sexually active women of child-bearing potential between the ages of 18 and 50 (average age 28.5 years) were randomly assigned to use either the popular triphasic Ortho-Novum 7/7/7 or Cyclessa for six menstrual cycles. Both OCs proved equally effective at preventing pregnancy, but women who used Cyclessa had significantly less breakthrough bleeding or spotting--11.0% vs 15.5%. The Cyclessa group also experienced an average weight loss of 0.2 kg (about -0.4 lbs) compared with an average weight gain in the Ortho-Novum 7/7/7 group of 0.1 kg (about +0.2 lbs)--a small difference, admittedly, but a statistically significant one (meaning it probably did not occur by chance).

There were no significant differences in the rates of side effects normally associated with combination OCs and no other notable differences overall in safety.

YASMIN: novel progestin, better weight control

The monophasic Yasmin uses 30 mcg of estrogen and 3.0 mg of drospirenone, a novel progestin that is remarkably similar to natural progesterone. In clinical comparison with conventional OCs, Yasmin has been on par with its competitors in efficacy, safety, and cycle control but has also been associated with improvement in skin conditions (acne, seborrhea) and improved sense of well-being. As its chief benefit, however, Yasmin appears to offer better weight control by reducing water retention.

Women with liver, kidney, or adrenal problems should not take Yasmin because there is a risk of potassium levels becoming dangerously high. Yasmin may not be appropriate in the presence of several other drugs, including certain over-the-counter pain relievers, potassium sparing diuretics, potassium supplements, ACE inhibitors, and angiotensin-II receptor antagonists.

Who needs another birth control pill?

Consistent use of an effective birth control method is the primary requirement for successful contraception. According to a recent survey commissioned by the National Women's Health Resource Center (www.healthywomen.org), 47% of women who've used OCs in the past five years were dissatisfied enough to change brands or stop using them altogether. Changing the type of progestin, the estrogen dose, or the dosing schedule of either has helped many women find an OC they can live with. Women who have weight problems on the Pill because of water retention may want to ask their physician about Yasmin. OC users interested in lowering their estrogen exposure without sacrificing cycle control may want to investigate Cyclessa.