I’ve read that lots of couples over 35 seek tests even before trying.
I think this is panic speaking as I don't think it's true at all.
www.theatlantic.com/magazine/archive/2013/07/how-long-can-you-wait-to-have-a-baby/309374/
The widely cited statistic that one in three women ages 35 to 39 will not be pregnant after a year of trying, for instance, is based on an article published in 2004 in the journal Human Reproduction. Rarely mentioned is the source of the data: French birth records from 1670 to 1830. The chance of remaining childless—30 percent—was also calculated based on historical populations.
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One study, published in Obstetrics & Gynecology in 2004 and headed by David Dunson (now of Duke University), examined the chances of pregnancy among 770 European women. It found that with sex at least twice a week, 82 percent of 35-to-39-year-old women conceive within a year, compared with 86 percent of 27-to-34-year-olds. (The fertility of women in their late 20s and early 30s was almost identical—news in and of itself.)
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Another study, released this March in Fertility and Sterility and led by Kenneth Rothman of Boston University, followed 2,820 Danish women as they tried to get pregnant. Among women having sex during their fertile times, 78 percent of 35-to-40-year-olds got pregnant within a year, compared with 84 percent of 20-to-34-year-olds. A study headed by Anne Steiner, an associate professor at the University of North Carolina School of Medicine, the results of which were presented in June, found that among 38- and 39-year-olds who had been pregnant before, 80 percent of white women of normal weight got pregnant naturally within six months (although that percentage was lower among other races and among the overweight). “In our data, we’re not seeing huge drops until age 40,” she told me.
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In Dunson’s study of modern women, the difference in pregnancy rates at age 28 versus 37 is only about 4 percentage points. Fertility does decrease with age, but the decline is not steep enough to keep the vast majority of women in their late 30s from having a child. And that, after all, is the whole point.
I am 39 years old in may. Does that mean you are currently 38 - in which case I really cant see why you wouldn't give it 6 months of actually trying. Anecdotally I know many women who got pg in late 30 early 40s - I wouldn't put it off any longer but I would seriously try TTC.