Depo-Provera and Pregnancy

December 25, 2004 6:35 PM

If someone became pregnant while on the shot, what would happen? This PDF says that the effects are minimal, but also sternly warns one to get off of Depo Provera immediately if pregnant, which leaves me thinking they're leaving something out. What are they afraid will happen? If birth controls change the uterine lining, doesn't that affect the fetus too? What happens to the children of the 3/1000 women who get pregnant on D-P?

Note: I'm not pregnant. Just looking for more info.

posted by heatherann to health & fitness (5 answers total)

maybe they miscarry?
posted by amberglow at 7:16 PM on December 25, 2004

Call your local 24 hr. pharmacist. They are a wealth of knowledge that rarely gets "tapped".
posted by 6:1 at 7:53 PM on December 25, 2004

A quick scan of pubmed seems to indicate that there may be an increased risk of ectopic pregnancy after conception with depo-provera, but this seems to never have been satisfactorially established; for example, the most recent study that I found seems to indicate that there is not a substantial difference in outcome from normal for pregnancies on d-p. I'd imagine that this is what the doctor would particularly want to monitor should conception occur. Uterine lining changes matter less once the fetus is implanted; should ovulation and fertilization occur and the zygote implant, progesterone levels will be very high anyway throughout pregnancy as the zygote will quickly begin to secrete chorionic gonadotropin, which will drive up natural progesterone secretion by the corpus luteum. This is in fact what the depo-provera injection is imitating; high progesterone levels are an indicator of pregnancy, interrupting the development of further ova while pregnancy (or the d-p shot) is ongoing.
As to Amberglow's link, continuous menstruation is a common side-effect of progestin-type contraceptives; while the poster seems to be experiencing this to excess, i doubt that it is caused by any kind of miscarriage.
Nobody should construe anything of what I've said here as any kind of medical advice: IA-definitely-NAD, just a grad student.
posted by monocyte at 9:08 PM on December 25, 2004

A pair of friends of mine, now married, had this exact thing happen. They ended up with twins. It was unexpected and confusing, because it wasn't clear for a very, very long time that the woman of the pair was pregant.

The boys were born a little over two months prematurely, but other than that, they're doing just fine now. She's carried two other kids to date. The worst thing that happened seemed to be the premature delivery, and, well, the fact the man just doesn't have any time to hang out anymore now that he's got such a large family. ;)
posted by eschatfische at 6:54 PM on December 26, 2004

Mostly nothing happens, and the warnings are to protect from liability, not to warn against a real phenomenon. Provera mimics progesterone, and the first thing that happens in pregnancy is that levels of human chorionic gonadotropin skyrocket, causing massive amounts of progesterone-effect that dwarf the picayune amounts caused by Provera. Estrogen levels skyrocket in pregnancy too - the contents of any hormonal contraceptive would be completely negligible as early as week 6.

It's the interruption in rhythmicity that allows contraceptives to work at all; nothing inherent about the hormones themselves.

You might have worked it out yourself, actually: the FDA allows this product to be recommended for reproductive-age, sexually active women. Do you suppose they would allow it if it was known to cause birth defects when it failed to work?

Now that's an explanation for the 3/1000. If you want an explanation about whether there isn't an excess 1/100000000 birth defect, premature birth, ectopic, or whatever owing to this stuff, you'd have to look elsewhere - I don't know the answer.
posted by ikkyu2 at 9:30 PM on December 27, 2004