THURSDAY, June 11, 2009 (HealthDay News) -- Postpartum anxiety may delay puberty in biological and adopted daughters, research on mice has found.
The study found that mice with low levels of the hormone prolactin in early pregnancy had substantial anxiety after giving birth and that their female offspring had delayed onset of puberty.
Prolactin, which is associated with lactation, is believed to protect against anxiety, according to a news release about the study from the Endocrine Society.
In the study, the researchers divided mice into four groups: mothers with normal prolactin and their offspring; mothers with low prolactin and their offspring; and two mixed groups, mothers with low prolactin raising female offspring of mice with normal prolactin levels, and mothers with normal prolactin levels raising the female offspring of mice with low levels of prolactin.
Puberty was delayed for the young mice in the low-prolactin group and in both mixed groups -- mice born to an anxious mother or raised by an anxious mother.
"Remarkably, puberty was still delayed even if the daughters of anxious mothers were raised by non-anxious mice," said lead study author Caroline Larsen, a postdoctoral fellow at the University of Otago in Dunedin, New Zealand. "And delayed puberty also occurred in daughters born to non-anxious mothers who were raised by anxious mothers," she noted.
"Postpartum anxiety disorders are poorly understood and difficult to treat," Larsen said. "There is growing evidence that untreated anxiety disorder during pregnancy may contribute to premature birth and also can have major and lasting adverse effects on the infant's development and behavior," she added.
Women have a higher incidence of anxiety disorders during pregnancy and for two years after giving birth, noted Larsen.
The study was presented Wednesday at the Endocrine Society annual meeting in Washington, D.C.
The findings show that hormonal changes in early pregnancy, as well as changes in maternal behavior caused by these hormonal shifts, can alter brain development in the offspring and delay puberty, Larsen said.
Further research may show a similar mechanism occurs in humans.
"Finding the hormonal mechanisms that trigger the timing of puberty in mice may help identify potential targets for the prevention and treatment of delayed or early puberty in humans," she said.
Late puberty in humans is linked to shorter height and psychological problems, according to the study.
Nemours has more on delayed puberty.