Q: I think my girlfriend might be pregnant, but she is getting her first Depo Provera shot in exactly a week. If she is, it was conceived this evening, so will it be intelligent to follow through with the shot? Neither of us wants a child at our age. We have discussed this, but abortion is out of the question. Will the Depo shot, like birth control pills, abort the embryo if she is pregnant?
A: You are asking a very good question about contraception. Unfortunately, a shot of Depo Provera administered a week after conception will not abort an embryo. Fortunately, morning after pill is available, and it can be used up to 72 hours after the event, but Depo a week later won’t help.
Morning after pill
It basically consists of four moderate-dose birth control pills, taken two at a time, twelve hours apart. This high dose of estrogen prevents implantation into the uterus of the fertilized egg, and is fairly effective. Alas, this same high dose of estrogen can make you fairly nauseous, so it is always offered to patients some anti-nausea pills at the same time. There are kits for this purpose now available at pharmacies, but a regular pack of morning after pill will do the trick.
There is very little good data on the effects of medroxy progesterone (Depo Provera) on a developing pregnancy. The data on women taking birth control pills inadvertently during pregnancy (not knowing they were pregnant) shows a very slight increased rate of birth defects. Remember, there is a baseline rate of 3% of birth defects in the population – any baby has about a 3% chance of being born with some birth defect. So if someone were to have a baby with a birth defect from some unknown cause, but would blame herself for having taken a medication, the best thing to do is avoid the medicine.
Probably the safest thing to do is to take morning after pill, wait until your girlfriend gets her next period, and be very careful to use both condoms and contraceptive foam until that period. When she gets her period, that would be a very opportune time for the Depo Provera injection.