Babies are born earlier and smaller when males are scarce

(Medical Xpress)—In communities where Dad is more likely to be missing from the picture, more babies are born prematurely and of lower weight, according to a researcher from the University of Michigan School of Public Health and the Institute for Social Research Population Studies Center.

In a study reported in the , Daniel Kruger, research assistant professor in and health education, found that when males are scarce it often negatively impacts —possibly from subconscious regulation of maternal investment in the pregnancy, Kruger said.

"I don't think any woman is consciously thinking, 'I should have a .' It is likely a non-conscious system regulated by hormones, etc., that is influenced by both conscious and non-conscious processes." Kruger said the outcome is related to investment trade-offs with deep histories. "This system evolved over many, many generations before modern times when infant and were much higher. There was a very real risk that when conditions were poor, their infant or child would die. It would make sense for the mothers to conserve their resources so that they would have more chance of having another child when times were better. Again, this is not a conscious decision, but a system that was effective in the very long run."

Kruger, and students Jillian Clark and Sarah Vanas from the College of Literature, Sciences and the Arts, combined year 2000 birth records aggregated by county from the U.S. with 2000 U.S. Decennial Census data. Across the 450 counties, they calculated the proportions that were premature, defined as less than 37 weeks gestation, and those with birth weight under 5.5 pounds. They developed a path model that took into account the ratio of men to women ages 18-64, single mother households as a proportion of families with children, socio-economic status, the degree of male scarcity, and other factors.

Kruger said the public health community has worked to support single mothers in their pregnancies with interventions that follow a standard medical model but now should also work to "assess the level of support that women expect to have from their partners, as well as family members and others in their social networks."

"If possible, we should increase men's involvement and support during pregnancy and reinforce the expectation that he will be around to help raise the child. This does not just have to be financial support; it can be spending time with the child, taking care of him/her, teaching him/her skills, etc."

Related Stories

Too posh to push? The increasing trend for cesarean section

date May 17, 2011

During the last thirty years there has been an increase in the number of babies born by Caesarean section. New research published in BioMed Central's open access journal BMC Public Health shows that there has also been a ...

Sad mothers have small babies

date Aug 25, 2010

Clinical depression and anxiety during pregnancy results in smaller babies that are more likely to die in infancy, according to new research published in the open access journal BMC Public Health. The study, which focuse ...

Recommended for you

Domestic violence deters contraception

date 4 hours ago

Domestic violence takes many forms. The control of a woman's reproductive choices by her partner is one of them. A major study published in PLOS One, led by McGill PhD student Lauren Maxwell, showed that women who are ab ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.