The first study of fluoridated water specifically in the first 3 months of pregnancy was released in 1993. Fluoridated water reduced almost all adverse outcomes of pregnancy. Serious birth defects were reduced by 40%, with a 95% confidence interval of 20-60%. No adverse outcomes of pregnancy were increased by fluoridated water in the first 3 months of pregnancy. (Aschengrau 1993, Archives of Environmental Health 48(2):105. This study is discussed in the heart section.)

The RDA people seem to have finally given their tacit support of fluoride in pregnancy (note the source), and even to early pregnancy in the sense that they support fluoride for adults in general: "Adults may also derive some benefit [for preventing dental caries] from a fluoridated water supply or a 1-mg fluoride supplement per day...". (National Academy of Sciences 1990. Nutrition During Pregnancy. Page 311.) A few years later we finally had an official recommendation specifically for pregnancy. The AI (adequate daily intake, which is the lower limit, for F from all sources) for pregnancy has been set at 3.1 mg F. (Institute of Medicine, Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride, 1997.)

A prominent expert on women's health and nutrition has recommended 2 mg F in the section of her book about early pregnancy. (Somer E.  Nutrition for a healthy pregnancy.  H. Holt & Co. 1995.)

A trial based on the mother's fluoride status at birth found the growth in infancy slightly higher, with about a 10% difference from the lowest fluoride to the highest. (Bergmann 1991, Trace elements in nutrition of children II, ed Chandra, Nestle Nutrition Workshop Series 23:105.)

At least one group of researchers recommends preventing low birth weight as a way to prevent birth defects. Nutritional factors are suspected. They report a striking coincidence of low birth weight and birth defects. For example, the lowest weight group (less than 1500 g) had a birth defect rate of 16.2%, compared to the highest weight group (over 4000g) at only 3.2%. (Mili 1991, AJDC  145:1313.)

There was a large study on fluoride safety after a cancer study made the news. The US Public Health Service found that even in areas with extraordinarily high water fluoride birth defects have not been reported among children born in these areas.  (1991 Review of fluoride benefits and risks.. Teratologic and developmental effects are reviewed on pages 67-9.)

Lab work was reported that showed how much fluoride a mother has to take to have some leftovers appear in the amniotic fluid. (To get to the amniotic fluid fluoride has to pass from the mothers blood stream to the fetus, then pass through the fetus.) The smallest dose tested (.25 mg F) was enough to show in the amniotic fluid, roughly doubling the background levels. It took at least 1.25 mg to make the levels start to rise again (implying at least partial satisfaction of both bodies). The mothers were 3 to 4 months into pregnancy at the time of the test. (Brambilla 1994, Archives of Oral Biology 39(11):991.)

The normal blood tests taken during pregnancy still do not check for fluoride, but there was finally a report on the blood levels of fluoride in modern pregnant women. They were lower than average. (This was a limited test, with only 4 pregnant women in a more general group of about 100 women. Two of them had levels so low as to be undetectable. Grandjean 1992, Scandinavian Journal of Clinical Laboratory Investigation  52(4):321.)

The worlds leading authority on prenatal fluoride came out with an excellent paper on the role of fluoride in early pregnancy and has a large human study in progress. (Glenn FB, Glenn WD, Burdi AR. Prenatal fluoride for growth and development: Part X. ASDC Journal of Dentistry for Children Sept-Oct 1997; 64(5):317-21. The length of the fetal hamster incisors increased [about 10%] in concert with the amount of prenatal fluoride given...  There are also some color photos of ameloblasts and other tooth development cells looking beautifully more well developed because of prenatal fluoride in humans.)