Pregnant women needs excess proteins. But taking more beef for that purpose is not good for their offspring. The research suggests that those men born to beef taken mothers had lower sperm count compared to others. While the study did not found the case of infertility but they found reduced fertility. They call them sub-fertile men.
The effect of beef intake on pregnant women was believed to be due the growth hormones. These hormones are present in beef. These are used to increase the growth rate of cattle. The hormones do not become metabolic when the cattle died.
Natural and synthetic hormones were used in promoting growth of cattle in the United States and Canada. Estradiol, Progesterone and testosterone were natural hormones and zeranol, trenbolone acetate and melengestrol acetate were the synthetic hormones used for promoting growth of cattle.
Pregnant women need not stop taking in beef completely. But they have to reduce the intake by a significant amount. They can go for organic beef or any other protein rich food as proteins are needed for pregnant women.