Preterm Birth, Fetal Growth, and Age at Menarche among Women Exposed Prenatally to Diethylstilbestrol (DES).

Hatch, E.E., Troisi, R., Wise, L.A., Titus-Ernstoff, L., Hyer, M., Palmer, J.R., Strohsnitter, W., Robboy, S.J., Herbst, A.L., Kaufman, R.H., Noller, K., Hoover, R.N. Reproductive Toxicology 2009

Research has suggested that early life characteristics, such as size at birth and age at menarche, may be associated with health conditions later in life. For example, some studies have suggested that low birth weight babies tend to have a higher risk of cardiovascular disease later in life. Other studies have shown that women who begin having periods at a young age have a slightly higher risk of breast cancer than those who begin menstruation later.

Although there has been a great deal of research on health of the 2nd generation (DES daughters) later in life, little attention has been paid to whether they were similar in terms of birth weight and other early life factors. Results from one of the early clinical trials of DES suggested that it might be related to lower birth weight and a higher risk of preterm birth. We conducted a systematic evaluation of DES daughters participating in the NCI DES Follow-up Study to determine whether there were any differences in birth weight, length of gestation, and the average age of first menstruation in the DES-exposed compared to unexposed daughters.

We found that there was a 2 to 3 fold increase in risk of having been born prematurely (before 37 weeks gestational age) among the DES-exposed compared to unexposed daughters. On average, DES daughters tended to weigh slightly less at birth, and there was also a 60% higher risk of being born too small, or small for gestational age (SGA), defined as less than the 10th percentile of birth weight at each gestational age. We found stronger effects for birth weight, SGA, and preterm birth among women who were participants in the original DESAD study, as compared to those who were in the Dieckmann clinical trial, suggesting that part of the effect may have been due to the higher risk pregnancies among the exposed women and not solely to DES exposure.

When we evaluated the risk of having started menstruation before age 11, we found no difference between the DES exposed and unexposed daughters. However, DES daughters did have a small increased risk (40%) of starting menarche very young-at age 10 or less-but this was based on very small numbers of participants who had very early menstruation.

In summary, DES exposed daughters appeared to weigh slightly less and have a higher risk of being born prematurely than unexposed daughters. They also were somewhat more likely to have begun menstruating at age 10 or younger. These effects may have a small impact on the risk of some diseases occurring later in life.

** PubMed abstract for this article **