They are less likely to have another miscarriage, and are also less likely to experience a caesarean section, deliver prematurely or have low-birth weight babies, the study showed.
The findings, published in the British Medical Journal, are likely to be controversial.
The World Health Organisation (WHO) recommends that women who experience a miscarriage should wait at least six months before getting pregnant again, and other medical authorities suggest holding off even longer.
To get a clearer picture, researchers led by Sohinee Bhattacharya at the Aberdeen Maternity Hospital in Scotland reviewed the medical histories of more than 30,000 women in Scotland who had a miscarriage in their first pregnancy and then became pregnant again between 1981 and 2000.
“Our research shows that women who conceive within six months of an initial miscarriage have the best reproductive outcomes and the lowest complication rates in a subsequent pregnancy,” they concluded.
“It is unnecessary for women to delay conception after a miscarriage.”
The results held true even though the women who conceived within half-a-year were, on average, two years older than the women who waited at least 24 months.
Differences in socioeconomic level did not affect the outcome.
The study pointed out that delays in getting pregnant were perhaps more of a issue in wealthy societies, where women often choose to wait until they are older to have children.
“Women over 35 are more likely to experience difficulties in conceiving and women aged 40 have a 30 percent chance of miscarriage, which rises to 50 percent in those aged 45 or more,” the study noted.
An earlier study of more than 250,000 Latin American women found that an interval of six months or less between pregnancies was linked to a higher risk for the mother and the late-stage foetus or newborn, including maternal anaemia, low birth weight and premature delivery in the next pregnancy.
But the study — the basis for the WHO recommendations — did not distinguish between induced abortions and miscarriages, which could have affected the findings, Bhattacharya said.
On average, approximately one in five pregnancies end in miscarriage before the 24th week.