I heard that conceiving with in vitro fertilization means a higher risk of miscarriage. Does that mean I should just keep trying naturally even though we have trouble getting pregnant?
It's true that there is some research showing that pregnancies conceived via in vitro fertilization (IVF) carry a slightly increased risk of miscarriage compared to spontaneous pregnancies in general. The exact level of the increased risk varies by study.
However, most researchers do not believe that the reason for the increased risk relates to the IVF procedure. Rather, it is more likely that increased risk of miscarriage after IVF (or other infertility treatment) has more to do with the underlying reasons for the infertility treatment. Patients who have a need for in vitro fertilization may simply be in a higher risk category for miscarriage regardless of the means of conception, unfair as that may be. There are several reasons why this might be true, ranging from the higher average age of parents to the possibility of underlying health conditions, but most possible explanations are not related to the IVF procedure itself.
So, don't be dissuaded from pursuing IVF if you need it. Talk to your doctor to develop a plan for what works best for your situation. It is possible that use of preimplantation genetic diagnosis may reduce your risk of miscarriage in an IVF pregnancy if you have already have history of past miscarriages prior to the treatment.
Munné S, Fischer J, Warner A, Chen S, Zouves C, Cohen J; Referring Centers PGD Group. "Preimplantation genetic diagnosis significantly reduces pregnancy loss in infertile couples: a multicenter study." Fertil Steril. 2006 Feb;85(2):326-32.
Tummers, Phillippe, Paul De Sutter and Marc Dhont. "Risk of spontaneous abortion in singleton and twin pregnancies after IVF/ICSI." Human Reproduction Aug 2003. 18(8): 1720-1723.
Wang, Jim X., Robert J. Norman and Allen J. Wilcox. "Incidence of spontaneous abortion among pregnancies produced by assisted reproductive technology." Human Reproduction Feb 2004. 19(2):272-277.