Who should get ellaOne? This a difficult question to answer as the superior efficacy is equivocal and it would be inappropriate to give it to all women presenting for emergency contraception. Some have tried to identify those who might be at greater risk of pregnancy to target UPA, for example younger women or those who have had intercourse during the more risky days in the cycle. The recent meta-analysis by Glasier and colleagues helps to identify women who might benefit from the new emergency contraceptive.

Age: None of the published, whether of LNG or UPA, have shown any difference in the efficacy of LNG or UPA by age. Targeting younger women for UPA does not make sense.

Time in cycle: Numberous studies have shown that we are poor at predicting fertility from day in the menstrual cycle. Targeting high risk women is difficult. How do we target those at greater risk for UPA?

BMI: We have some good data on BMI. The Glasier review (2011) on BMI and efficacy combined the results from the earlier Creinin trial with Glasier from the 2010 trial. They found no statistical difference between UPA and LNG in women with BMI less than 25. Although they did not do the statistical test in the paper, were 15 pregnancies in over 1,110 women using LNG and 12 in over 1,100 women using UPA.

Adapted from Glasier 2011

Glasier 2011.pdf

With over 1,100 women using both UPA and LNG, if there is a difference it would be evident.

The next graph uses the same data showing the difference in pregnancy rate between UPA and LNG for different levels of BMI. It shows that there is no difference in pregnancy rate for women with BMI less than 25, that is normal or light women, the majority of our clients (p=0.58).

Delay in treatment: Piaggio’s recent paper on LNG which combined the data from four WHO trials found no increase in failure rate to Day 4, but a significant rise in pregnancy rate following treatment 5 days after intercourse. LNG appears to be efficacious up to Day 4 but there is some doubt if it is of any use on Day 5.

Piaggio 2100

Piaggio 2011.pdf

To whom should we give ellaOne?

I suggest we offer UPA to clients with BMI over 30 and those who attend on the 5th after intercourse. See the green calls in the table below. The evidence supports the use of LNG for all women who have BMI less than 25, and those who attend less than 4 days after intercourse. In the Glasier study, the majority of women were in the green cells.

UPA appears to me of benefit only to women who are overweight. It is difficult to justify the use of UPA for normal weight women who seek treatment less then 5 days after intercourse when LNG is likely to be as effective without the drawbacks associated with UPA use, including the concerns about giving UPA to a woman already pregnant and the interference with hormonal contraception taken immediately after.

I am unsure what we should do for women with BMI 25-30. The difference in pregnancy rate between UPA and LNG is 1%, but with only 300 women in each group the difference was not significant (p=0.14) and so could be due to chance. The extra cost of ellaOne and the reduced availability could swing it in LNG's favour.