Women who've had a miscarriage don't need to wait for months or years to attempt to become pregnant again, a study published online in the British Medical Journal concludes. The study examined outcomes for almost 31,000 Scottish women who suffered a miscarriage and became pregnant again after various intervals of time. Those who waited for months or years to attempt another pregnancy fared worse by many measures, including whether they had another miscarriage, had a pregnancy outside the uterus (an ectopic pregnancy) or whether they delivered a live infant. The study clearly seems to contradict World Health Organization recommendations that women wait at least six months after miscarriage to attempt another pregnancy, and certainly guidelines of other organizations suggesting an interval even longer than that.
Miscarriage, is, of course, a subject many of us don't quite know how to handle. But as Rick points out in the podcast, up to 50% of women who attempt pregnancy will experience a miscarriage. That's huge, and here's why we know.
Back in the dark ages, happily before I can remember, women were diagnosed as being pregnant by injecting their urine into a female mammal, often a rabbit, then examining the animal's ovaries days later to see if ovulation had been induced. This was because human chorionic gonadotrophin, or HCG, produced very early in pregnancy and found in a woman's urine, can produce ovulation in another female animal. The animal was sacrificed to examine its ovaries, thus the term, "killed the rabbit."
Today we have extremely accurate over the counter tests to determine if a woman is pregnant, and very soon after conception. These tests rely on the presence of HCG, too, and have given us some very revealing data: about one-fourth of pregnancies result in miscarriage. That may be an underestimate as many pregnancies fail before a woman even attempts to determine if she is pregnant.
Why such a high rate of failure? Very early miscarriages are almost always the result of genetic abnormalities incompatible with life. Viewed through this lens, clearly nature is at work in assuring that such an offspring will not survive. But such a clinical stance fails to take into account the often rather significant emotional toll of miscarriage.
Since we now know so very early in pregnancy that a woman is pregnant, prospective parents may invest a lot of anticipation and joy in the prospect of a baby at a time when the pregnancy itself may be precarious. Add to this the fact that many women are delaying childbearing until years when fertility is undeniably declining, and the stakes are high indeed. So these study findings say to me, if you've experienced a miscarriage but feel emotionally ready to try again, do so. That's of course in the absence of any medical reason to wait.
Other topics this week include the best time to start dialysis in folks with kidney disease in NEJM, the use of medications to prevent a second stroke in Archives of Neurology, and a decline (YAY!) in MRSA infections in JAMA. Until next week, y'all live well.