There has always been concern, with data to support it, that if a woman gets pregnant sooner than about 6 months after a previous pregnancy, the complications such as low birth weight, placental problems and preterm labor are more frequent than in a woman who has waited longer after her pregnancy to become pregnant. There are many factors involved in the choice or circumstances of becoming pregnant. Also, we do not know if the outcome after a previous term pregnancy is going to be the same as after a pregnancy that miscarries.
You would think that it would be easy to determine when the best time is to get pregnant after a miscarriage to minimize a future miscarriage (spontaneous abortion) or minimize a problem with a low birth weight or premature infant. It is not easy however, because the decision to try to conceive depends upon many factors which are influenced by a woman’s previous reproductive performance. If a woman knows she has difficulty conceiving or is getting older and feels time is running out, she will try to conceive as quickly as possible after a previous pregnancy loss. We know that women who are older or who are subfertile will have higher miscarriage rates so if you include their data, it will always look as if a short interpregnancy interval will lead to a higher miscarriage rate.
As far as getting pregnant after a miscarriage, you can start trying whenever you want because we do not know of adverse data following just a spontaneous miscarriage. In fact some older data implies that there is no increase in the abortion rate in women who quickly conceive following a previous spontaneous abortion. Following a pregnancy, it appears that the best time to conceive with the least frequency of complications is about 18-23 months. Under 6 months the percent increase in problems is enough that most physicians do not recommend becoming pregnant.
You may want to know what the chance of having another miscarriage is if you have had one or more already. Based upon clinically recognized pregnancies, not chemical ones, the chance of a subsequent miscarriage according to one study is:
• Overall general rate 11%
• After one miscarriage 16%
• After two miscarriages 25%
• After three miscarriage 45%
• After four miscarriages 54%
While the evidence does not clearly indicate that conceiving too soon leads to an increased incidence of miscarriage, there is indirect evidence that if you do get pregnant sooner than 6 months after a pregnancy of any type, that the outcome may lead to complications if pregnancy occurs. For that reason, I support taking a break of at least 6 months before trying to conceive again after a miscarriage. If you do get pregnant in that time, o.k. But don’t put nonstop pressure on yourself to conceive.
