Almost half of women who at first had trouble ended up having a baby despite not getting fertility treatment.
Compared to women who opted for treatment with hormones or in vitro fertilization, the success rate was only slightly lower.
Researchers suspect many of these women are not infertile, but sub-fertile. That means nothing is clearly wrong .
Couples who had trouble conceiving should be optimistic they can get pregnant on their own.
The study in the journal Fertility and Sterility is part of a long-term study of more than 7,000 Australian women.