Although it is important for pregnant women to receive prenatal care, there is no hard evidence to back the argument that it pays for itself by averting future medical costs.

Many contend that the cost of prenatal care is more than offset by a reduction in the number of premature babies and low birth weight babies, whose medical costs can be astronomical. Papers in scholarly journals have even stated the specific savings from prenatal care- for every $1 spent, one paper said the savings would be $1.70, another $2.57 and a third $3.38. However, a review of more than 100 such papers reveals:

• Only 12 papers make specific claims about the cost savings of prenatal care - and all have serious flaws in methodology that make their findings questionable.

• Most of the other papers reviewed cite one or more of the 12 flawed papers as their proof that prenatal care pays for itself.

The big problem with the studies is that they make assumptions about the effectiveness of care and the medical costs of pregnancy that the evidence does not support. For example:

• They assume that prenatal care largely prevents the births of very premature babies - those born in or before the 28th week of pregnancy.

• But if prenatal care helps prevent prematurity at all, it prevents births after the 28th week, when medical problems are less severe and less costly.

• Some of the studies assume that routine prenatal care is enough to help poor women with complex problems.

• However, most women at high risk of having premature babies need intensive, more expensive care.

Some of the studies do not take into account differences in income, substance abuse, maternal age, motivation and ability to seek timely care - all factors that could have an impact on the health or weight of the baby.

The lack of overall cost savings does not mean that pregnant women should avoid prenatal care, which can benefit both mother and child. Rather, it calls into question whether cost savings is the appropriate criterion by which to judge prenatal care programs.

Source: Jane Huntington and Frederick A. Connell, "For Every Dollar Spent - The Cost-Savings Argument for Prenatal Care," New England Journal of Medicine, Vol. 331, No. 19, November 10, 1994; and Gina Kolata, "Reassessing Costs of Prenatal Care," New York Times, November 10, 1994.